how to report literature review

Purdue Online Writing Lab Purdue OWL® College of Liberal Arts

Writing a Literature Review

Welcome to the Purdue OWL

This page is brought to you by the OWL at Purdue University. When printing this page, you must include the entire legal notice.

Copyright ©1995-2018 by The Writing Lab & The OWL at Purdue and Purdue University. All rights reserved. This material may not be published, reproduced, broadcast, rewritten, or redistributed without permission. Use of this site constitutes acceptance of our terms and conditions of fair use.

A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

• An introductory paragraph that explains what your working topic and thesis is
• A forecast of key topics or texts that will appear in the review
• Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
• Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically Evaluate: Mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

• Summarize the key findings you have taken from the literature and emphasize their significance
• Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

• Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
• Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
• Qualitative versus quantitative research
• Empirical versus theoretical scholarship
• Divide the research by sociological, historical, or cultural sources
• Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

• It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
• Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
• Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
• Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, automatically generate references for free.

• Knowledge Base
• Dissertation
• What is a Literature Review? | Guide, Template, & Examples

What is a Literature Review? | Guide, Template, & Examples

Published on 22 February 2022 by Shona McCombes . Revised on 7 June 2022.

What is a literature review? A literature review is a survey of scholarly sources on a specific topic. It provides an overview of current knowledge, allowing you to identify relevant theories, methods, and gaps in the existing research.

There are five key steps to writing a literature review:

• Search for relevant literature
• Evaluate sources
• Identify themes, debates and gaps
• Outline the structure
• Write your literature review

A good literature review doesn’t just summarise sources – it analyses, synthesises, and critically evaluates to give a clear picture of the state of knowledge on the subject.

Instantly correct all language mistakes in your text

Be assured that you'll submit flawless writing. Upload your document to correct all your mistakes.

Table of contents

Why write a literature review, examples of literature reviews, step 1: search for relevant literature, step 2: evaluate and select sources, step 3: identify themes, debates and gaps, step 4: outline your literature review’s structure, step 5: write your literature review, frequently asked questions about literature reviews, introduction.

• Quick Run-through
• Step 1 & 2

When you write a dissertation or thesis, you will have to conduct a literature review to situate your research within existing knowledge. The literature review gives you a chance to:

• Demonstrate your familiarity with the topic and scholarly context
• Develop a theoretical framework and methodology for your research
• Position yourself in relation to other researchers and theorists
• Show how your dissertation addresses a gap or contributes to a debate

You might also have to write a literature review as a stand-alone assignment. In this case, the purpose is to evaluate the current state of research and demonstrate your knowledge of scholarly debates around a topic.

The content will look slightly different in each case, but the process of conducting a literature review follows the same steps. We’ve written a step-by-step guide that you can follow below.

The only proofreading tool specialized in correcting academic writing

The academic proofreading tool has been trained on 1000s of academic texts and by native English editors. Making it the most accurate and reliable proofreading tool for students.

Correct my document today

Writing literature reviews can be quite challenging! A good starting point could be to look at some examples, depending on what kind of literature review you’d like to write.

• Example literature review #1: “Why Do People Migrate? A Review of the Theoretical Literature” ( Theoretical literature review about the development of economic migration theory from the 1950s to today.)
• Example literature review #2: “Literature review as a research methodology: An overview and guidelines” ( Methodological literature review about interdisciplinary knowledge acquisition and production.)
• Example literature review #3: “The Use of Technology in English Language Learning: A Literature Review” ( Thematic literature review about the effects of technology on language acquisition.)
• Example literature review #4: “Learners’ Listening Comprehension Difficulties in English Language Learning: A Literature Review” ( Chronological literature review about how the concept of listening skills has changed over time.)

You can also check out our templates with literature review examples and sample outlines at the links below.

Download Word doc Download Google doc

Before you begin searching for literature, you need a clearly defined topic .

If you are writing the literature review section of a dissertation or research paper, you will search for literature related to your research objectives and questions .

If you are writing a literature review as a stand-alone assignment, you will have to choose a focus and develop a central question to direct your search. Unlike a dissertation research question, this question has to be answerable without collecting original data. You should be able to answer it based only on a review of existing publications.

Make a list of keywords

Start by creating a list of keywords related to your research topic. Include each of the key concepts or variables you’re interested in, and list any synonyms and related terms. You can add to this list if you discover new keywords in the process of your literature search.

• Social media, Facebook, Instagram, Twitter, Snapchat, TikTok
• Body image, self-perception, self-esteem, mental health
• Generation Z, teenagers, adolescents, youth

Search for relevant sources

Use your keywords to begin searching for sources. Some databases to search for journals and articles include:

• Your university’s library catalogue
• Google Scholar
• Project Muse (humanities and social sciences)
• Medline (life sciences and biomedicine)
• EconLit (economics)
• Inspec (physics, engineering and computer science)

You can use boolean operators to help narrow down your search:

Read the abstract to find out whether an article is relevant to your question. When you find a useful book or article, you can check the bibliography to find other relevant sources.

To identify the most important publications on your topic, take note of recurring citations. If the same authors, books or articles keep appearing in your reading, make sure to seek them out.

You probably won’t be able to read absolutely everything that has been written on the topic – you’ll have to evaluate which sources are most relevant to your questions.

For each publication, ask yourself:

• What question or problem is the author addressing?
• What are the key concepts and how are they defined?
• What are the key theories, models and methods? Does the research use established frameworks or take an innovative approach?
• What are the results and conclusions of the study?
• How does the publication relate to other literature in the field? Does it confirm, add to, or challenge established knowledge?
• How does the publication contribute to your understanding of the topic? What are its key insights and arguments?
• What are the strengths and weaknesses of the research?

Make sure the sources you use are credible, and make sure you read any landmark studies and major theories in your field of research.

You can find out how many times an article has been cited on Google Scholar – a high citation count means the article has been influential in the field, and should certainly be included in your literature review.

The scope of your review will depend on your topic and discipline: in the sciences you usually only review recent literature, but in the humanities you might take a long historical perspective (for example, to trace how a concept has changed in meaning over time).

Remember that you can use our template to summarise and evaluate sources you’re thinking about using!

Take notes and cite your sources

As you read, you should also begin the writing process. Take notes that you can later incorporate into the text of your literature review.

It’s important to keep track of your sources with references to avoid plagiarism . It can be helpful to make an annotated bibliography, where you compile full reference information and write a paragraph of summary and analysis for each source. This helps you remember what you read and saves time later in the process.

You can use our free APA Reference Generator for quick, correct, consistent citations.

To begin organising your literature review’s argument and structure, you need to understand the connections and relationships between the sources you’ve read. Based on your reading and notes, you can look for:

• Trends and patterns (in theory, method or results): do certain approaches become more or less popular over time?
• Themes: what questions or concepts recur across the literature?
• Debates, conflicts and contradictions: where do sources disagree?
• Pivotal publications: are there any influential theories or studies that changed the direction of the field?
• Gaps: what is missing from the literature? Are there weaknesses that need to be addressed?

This step will help you work out the structure of your literature review and (if applicable) show how your own research will contribute to existing knowledge.

• Most research has focused on young women.
• There is an increasing interest in the visual aspects of social media.
• But there is still a lack of robust research on highly-visual platforms like Instagram and Snapchat – this is a gap that you could address in your own research.

There are various approaches to organising the body of a literature review. You should have a rough idea of your strategy before you start writing.

Depending on the length of your literature review, you can combine several of these strategies (for example, your overall structure might be thematic, but each theme is discussed chronologically).

Chronological

The simplest approach is to trace the development of the topic over time. However, if you choose this strategy, be careful to avoid simply listing and summarising sources in order.

Try to analyse patterns, turning points and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred.

If you have found some recurring central themes, you can organise your literature review into subsections that address different aspects of the topic.

For example, if you are reviewing literature about inequalities in migrant health outcomes, key themes might include healthcare policy, language barriers, cultural attitudes, legal status, and economic access.

Methodological

If you draw your sources from different disciplines or fields that use a variety of research methods , you might want to compare the results and conclusions that emerge from different approaches. For example:

• Look at what results have emerged in qualitative versus quantitative research
• Discuss how the topic has been approached by empirical versus theoretical scholarship
• Divide the literature into sociological, historical, and cultural sources

Theoretical

A literature review is often the foundation for a theoretical framework . You can use it to discuss various theories, models, and definitions of key concepts.

You might argue for the relevance of a specific theoretical approach, or combine various theoretical concepts to create a framework for your research.

Like any other academic text, your literature review should have an introduction , a main body, and a conclusion . What you include in each depends on the objective of your literature review.

The introduction should clearly establish the focus and purpose of the literature review.

If you are writing the literature review as part of your dissertation or thesis, reiterate your central problem or research question and give a brief summary of the scholarly context. You can emphasise the timeliness of the topic (“many recent studies have focused on the problem of x”) or highlight a gap in the literature (“while there has been much research on x, few researchers have taken y into consideration”).

Depending on the length of your literature review, you might want to divide the body into subsections. You can use a subheading for each theme, time period, or methodological approach.

As you write, make sure to follow these tips:

• Summarise and synthesise: give an overview of the main points of each source and combine them into a coherent whole.
• Analyse and interpret: don’t just paraphrase other researchers – add your own interpretations, discussing the significance of findings in relation to the literature as a whole.
• Critically evaluate: mention the strengths and weaknesses of your sources.
• Write in well-structured paragraphs: use transitions and topic sentences to draw connections, comparisons and contrasts.

In the conclusion, you should summarise the key findings you have taken from the literature and emphasise their significance.

If the literature review is part of your dissertation or thesis, reiterate how your research addresses gaps and contributes new knowledge, or discuss how you have drawn on existing theories and methods to build a framework for your research. This can lead directly into your methodology section.

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a dissertation , thesis, research paper , or proposal .

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarise yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

The literature review usually comes near the beginning of your  dissertation . After the introduction , it grounds your research in a scholarly field and leads directly to your theoretical framework or methodology .

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the ‘Cite this Scribbr article’ button to automatically add the citation to our free Reference Generator.

McCombes, S. (2022, June 07). What is a Literature Review? | Guide, Template, & Examples. Scribbr. Retrieved 14 May 2024, from https://www.scribbr.co.uk/thesis-dissertation/literature-review/

Is this article helpful?

Shona McCombes

Other students also liked, how to write a dissertation proposal | a step-by-step guide, what is a theoretical framework | a step-by-step guide, what is a research methodology | steps & tips.

Get science-backed answers as you write with Paperpal's Research feature

What is a Literature Review? How to Write It (with Examples)

A literature review is a critical analysis and synthesis of existing research on a particular topic. It provides an overview of the current state of knowledge, identifies gaps, and highlights key findings in the literature. 1 The purpose of a literature review is to situate your own research within the context of existing scholarship, demonstrating your understanding of the topic and showing how your work contributes to the ongoing conversation in the field. Learning how to write a literature review is a critical tool for successful research. Your ability to summarize and synthesize prior research pertaining to a certain topic demonstrates your grasp on the topic of study, and assists in the learning process. 

Table of Contents

• What is the purpose of literature review? 
• a. Habitat Loss and Species Extinction: 
• b. Range Shifts and Phenological Changes: 
• c. Ocean Acidification and Coral Reefs: 
• d. Adaptive Strategies and Conservation Efforts: 

How to write a good literature review 

• Choose a Topic and Define the Research Question: 
• Decide on the Scope of Your Review: 
• Select Databases for Searches: 
• Conduct Searches and Keep Track: 
• Review the Literature: 
• Organize and Write Your Literature Review: 
• How to write a literature review faster with Paperpal? 
• Frequently asked questions 

What is a literature review?

A well-conducted literature review demonstrates the researcher’s familiarity with the existing literature, establishes the context for their own research, and contributes to scholarly conversations on the topic. One of the purposes of a literature review is also to help researchers avoid duplicating previous work and ensure that their research is informed by and builds upon the existing body of knowledge.

What is the purpose of literature review?

A literature review serves several important purposes within academic and research contexts. Here are some key objectives and functions of a literature review: 2  

1. Contextualizing the Research Problem: The literature review provides a background and context for the research problem under investigation. It helps to situate the study within the existing body of knowledge. 

2. Identifying Gaps in Knowledge: By identifying gaps, contradictions, or areas requiring further research, the researcher can shape the research question and justify the significance of the study. This is crucial for ensuring that the new research contributes something novel to the field. 

Find academic papers related to your research topic faster. Try Research on Paperpal  

3. Understanding Theoretical and Conceptual Frameworks: Literature reviews help researchers gain an understanding of the theoretical and conceptual frameworks used in previous studies. This aids in the development of a theoretical framework for the current research. 

4. Providing Methodological Insights: Another purpose of literature reviews is that it allows researchers to learn about the methodologies employed in previous studies. This can help in choosing appropriate research methods for the current study and avoiding pitfalls that others may have encountered. 

5. Establishing Credibility: A well-conducted literature review demonstrates the researcher’s familiarity with existing scholarship, establishing their credibility and expertise in the field. It also helps in building a solid foundation for the new research. 

6. Informing Hypotheses or Research Questions: The literature review guides the formulation of hypotheses or research questions by highlighting relevant findings and areas of uncertainty in existing literature. 

Literature review example

Let’s delve deeper with a literature review example: Let’s say your literature review is about the impact of climate change on biodiversity. You might format your literature review into sections such as the effects of climate change on habitat loss and species extinction, phenological changes, and marine biodiversity. Each section would then summarize and analyze relevant studies in those areas, highlighting key findings and identifying gaps in the research. The review would conclude by emphasizing the need for further research on specific aspects of the relationship between climate change and biodiversity. The following literature review template provides a glimpse into the recommended literature review structure and content, demonstrating how research findings are organized around specific themes within a broader topic. 

Literature Review on Climate Change Impacts on Biodiversity:

Climate change is a global phenomenon with far-reaching consequences, including significant impacts on biodiversity. This literature review synthesizes key findings from various studies: 

a. Habitat Loss and Species Extinction:

Climate change-induced alterations in temperature and precipitation patterns contribute to habitat loss, affecting numerous species (Thomas et al., 2004). The review discusses how these changes increase the risk of extinction, particularly for species with specific habitat requirements. 

b. Range Shifts and Phenological Changes:

Observations of range shifts and changes in the timing of biological events (phenology) are documented in response to changing climatic conditions (Parmesan & Yohe, 2003). These shifts affect ecosystems and may lead to mismatches between species and their resources. 

c. Ocean Acidification and Coral Reefs:

The review explores the impact of climate change on marine biodiversity, emphasizing ocean acidification’s threat to coral reefs (Hoegh-Guldberg et al., 2007). Changes in pH levels negatively affect coral calcification, disrupting the delicate balance of marine ecosystems. 

d. Adaptive Strategies and Conservation Efforts:

Recognizing the urgency of the situation, the literature review discusses various adaptive strategies adopted by species and conservation efforts aimed at mitigating the impacts of climate change on biodiversity (Hannah et al., 2007). It emphasizes the importance of interdisciplinary approaches for effective conservation planning. 

Strengthen your literature review with factual insights. Try Research on Paperpal for free!    

Writing a literature review involves summarizing and synthesizing existing research on a particular topic. A good literature review format should include the following elements. 

Introduction: The introduction sets the stage for your literature review, providing context and introducing the main focus of your review. 

• Opening Statement: Begin with a general statement about the broader topic and its significance in the field. 
• Scope and Purpose: Clearly define the scope of your literature review. Explain the specific research question or objective you aim to address. 
• Organizational Framework: Briefly outline the structure of your literature review, indicating how you will categorize and discuss the existing research. 
• Significance of the Study: Highlight why your literature review is important and how it contributes to the understanding of the chosen topic. 
• Thesis Statement: Conclude the introduction with a concise thesis statement that outlines the main argument or perspective you will develop in the body of the literature review. 

Body: The body of the literature review is where you provide a comprehensive analysis of existing literature, grouping studies based on themes, methodologies, or other relevant criteria. 

• Organize by Theme or Concept: Group studies that share common themes, concepts, or methodologies. Discuss each theme or concept in detail, summarizing key findings and identifying gaps or areas of disagreement. 
• Critical Analysis: Evaluate the strengths and weaknesses of each study. Discuss the methodologies used, the quality of evidence, and the overall contribution of each work to the understanding of the topic. 
• Synthesis of Findings: Synthesize the information from different studies to highlight trends, patterns, or areas of consensus in the literature. 
• Identification of Gaps: Discuss any gaps or limitations in the existing research and explain how your review contributes to filling these gaps. 
• Transition between Sections: Provide smooth transitions between different themes or concepts to maintain the flow of your literature review. 

Write and Cite as you go with Paperpal Research. Start now for free.   

Conclusion: The conclusion of your literature review should summarize the main findings, highlight the contributions of the review, and suggest avenues for future research. 

• Summary of Key Findings: Recap the main findings from the literature and restate how they contribute to your research question or objective. 
• Contributions to the Field: Discuss the overall contribution of your literature review to the existing knowledge in the field. 
• Implications and Applications: Explore the practical implications of the findings and suggest how they might impact future research or practice. 
• Recommendations for Future Research: Identify areas that require further investigation and propose potential directions for future research in the field. 
• Final Thoughts: Conclude with a final reflection on the importance of your literature review and its relevance to the broader academic community. 

Conducting a literature review

Conducting a literature review is an essential step in research that involves reviewing and analyzing existing literature on a specific topic. It’s important to know how to do a literature review effectively, so here are the steps to follow: 1  

Choose a Topic and Define the Research Question:

• Select a topic that is relevant to your field of study. 
• Clearly define your research question or objective. Determine what specific aspect of the topic do you want to explore? 

Decide on the Scope of Your Review:

• Determine the timeframe for your literature review. Are you focusing on recent developments, or do you want a historical overview? 
• Consider the geographical scope. Is your review global, or are you focusing on a specific region? 
• Define the inclusion and exclusion criteria. What types of sources will you include? Are there specific types of studies or publications you will exclude? 

Select Databases for Searches:

• Identify relevant databases for your field. Examples include PubMed, IEEE Xplore, Scopus, Web of Science, and Google Scholar. 
• Consider searching in library catalogs, institutional repositories, and specialized databases related to your topic. 

Conduct Searches and Keep Track:

• Develop a systematic search strategy using keywords, Boolean operators (AND, OR, NOT), and other search techniques. 
• Record and document your search strategy for transparency and replicability. 
• Keep track of the articles, including publication details, abstracts, and links. Use citation management tools like EndNote, Zotero, or Mendeley to organize your references. 

Review the Literature:

• Evaluate the relevance and quality of each source. Consider the methodology, sample size, and results of studies. 
• Organize the literature by themes or key concepts. Identify patterns, trends, and gaps in the existing research. 
• Summarize key findings and arguments from each source. Compare and contrast different perspectives. 
• Identify areas where there is a consensus in the literature and where there are conflicting opinions. 
• Provide critical analysis and synthesis of the literature. What are the strengths and weaknesses of existing research? 

Organize and Write Your Literature Review:

• Literature review outline should be based on themes, chronological order, or methodological approaches. 
• Write a clear and coherent narrative that synthesizes the information gathered. 
• Use proper citations for each source and ensure consistency in your citation style (APA, MLA, Chicago, etc.). 
• Conclude your literature review by summarizing key findings, identifying gaps, and suggesting areas for future research. 

Whether you’re exploring a new research field or finding new angles to develop an existing topic, sifting through hundreds of papers can take more time than you have to spare. But what if you could find science-backed insights with verified citations in seconds? That’s the power of Paperpal’s new Research feature!  

How to write a literature review faster with Paperpal?

Paperpal, an AI writing assistant, integrates powerful academic search capabilities within its writing platform. With the Research feature, you get 100% factual insights, with citations backed by 250M+ verified research articles, directly within your writing interface with the option to save relevant references in your Citation Library. By eliminating the need to switch tabs to find answers to all your research questions, Paperpal saves time and helps you stay focused on your writing.   

Here’s how to use the Research feature:  

• Ask a question: Get started with a new document on paperpal.com. Click on the “Research” feature and type your question in plain English. Paperpal will scour over 250 million research articles, including conference papers and preprints, to provide you with accurate insights and citations. 
• Review and Save: Paperpal summarizes the information, while citing sources and listing relevant reads. You can quickly scan the results to identify relevant references and save these directly to your built-in citations library for later access. 
• Cite with Confidence: Paperpal makes it easy to incorporate relevant citations and references into your writing, ensuring your arguments are well-supported by credible sources. This translates to a polished, well-researched literature review. 

The literature review sample and detailed advice on writing and conducting a review will help you produce a well-structured report. But remember that a good literature review is an ongoing process, and it may be necessary to revisit and update it as your research progresses. By combining effortless research with an easy citation process, Paperpal Research streamlines the literature review process and empowers you to write faster and with more confidence. Try Paperpal Research now and see for yourself.  

Frequently asked questions

A literature review is a critical and comprehensive analysis of existing literature (published and unpublished works) on a specific topic or research question and provides a synthesis of the current state of knowledge in a particular field. A well-conducted literature review is crucial for researchers to build upon existing knowledge, avoid duplication of efforts, and contribute to the advancement of their field. It also helps researchers situate their work within a broader context and facilitates the development of a sound theoretical and conceptual framework for their studies.

Literature review is a crucial component of research writing, providing a solid background for a research paper’s investigation. The aim is to keep professionals up to date by providing an understanding of ongoing developments within a specific field, including research methods, and experimental techniques used in that field, and present that knowledge in the form of a written report. Also, the depth and breadth of the literature review emphasizes the credibility of the scholar in his or her field.  

Before writing a literature review, it’s essential to undertake several preparatory steps to ensure that your review is well-researched, organized, and focused. This includes choosing a topic of general interest to you and doing exploratory research on that topic, writing an annotated bibliography, and noting major points, especially those that relate to the position you have taken on the topic. 

Literature reviews and academic research papers are essential components of scholarly work but serve different purposes within the academic realm. 3 A literature review aims to provide a foundation for understanding the current state of research on a particular topic, identify gaps or controversies, and lay the groundwork for future research. Therefore, it draws heavily from existing academic sources, including books, journal articles, and other scholarly publications. In contrast, an academic research paper aims to present new knowledge, contribute to the academic discourse, and advance the understanding of a specific research question. Therefore, it involves a mix of existing literature (in the introduction and literature review sections) and original data or findings obtained through research methods. 

Literature reviews are essential components of academic and research papers, and various strategies can be employed to conduct them effectively. If you want to know how to write a literature review for a research paper, here are four common approaches that are often used by researchers.  Chronological Review: This strategy involves organizing the literature based on the chronological order of publication. It helps to trace the development of a topic over time, showing how ideas, theories, and research have evolved.  Thematic Review: Thematic reviews focus on identifying and analyzing themes or topics that cut across different studies. Instead of organizing the literature chronologically, it is grouped by key themes or concepts, allowing for a comprehensive exploration of various aspects of the topic.  Methodological Review: This strategy involves organizing the literature based on the research methods employed in different studies. It helps to highlight the strengths and weaknesses of various methodologies and allows the reader to evaluate the reliability and validity of the research findings.  Theoretical Review: A theoretical review examines the literature based on the theoretical frameworks used in different studies. This approach helps to identify the key theories that have been applied to the topic and assess their contributions to the understanding of the subject.  It’s important to note that these strategies are not mutually exclusive, and a literature review may combine elements of more than one approach. The choice of strategy depends on the research question, the nature of the literature available, and the goals of the review. Additionally, other strategies, such as integrative reviews or systematic reviews, may be employed depending on the specific requirements of the research.

The literature review format can vary depending on the specific publication guidelines. However, there are some common elements and structures that are often followed. Here is a general guideline for the format of a literature review:  Introduction:   Provide an overview of the topic.  Define the scope and purpose of the literature review.  State the research question or objective.  Body:   Organize the literature by themes, concepts, or chronology.  Critically analyze and evaluate each source.  Discuss the strengths and weaknesses of the studies.  Highlight any methodological limitations or biases.  Identify patterns, connections, or contradictions in the existing research.  Conclusion:   Summarize the key points discussed in the literature review.  Highlight the research gap.  Address the research question or objective stated in the introduction.  Highlight the contributions of the review and suggest directions for future research.

Both annotated bibliographies and literature reviews involve the examination of scholarly sources. While annotated bibliographies focus on individual sources with brief annotations, literature reviews provide a more in-depth, integrated, and comprehensive analysis of existing literature on a specific topic. The key differences are as follows: 

References 

• Denney, A. S., & Tewksbury, R. (2013). How to write a literature review.  Journal of criminal justice education ,  24 (2), 218-234. 
• Pan, M. L. (2016).  Preparing literature reviews: Qualitative and quantitative approaches . Taylor & Francis. 
• Cantero, C. (2019). How to write a literature review.  San José State University Writing Center . 

Paperpal is an AI writing assistant that help academics write better, faster with real-time suggestions for in-depth language and grammar correction. Trained on millions of research manuscripts enhanced by professional academic editors, Paperpal delivers human precision at machine speed.  

Try it for free or upgrade to  Paperpal Prime , which unlocks unlimited access to premium features like academic translation, paraphrasing, contextual synonyms, consistency checks and more. It’s like always having a professional academic editor by your side! Go beyond limitations and experience the future of academic writing.  Get Paperpal Prime now at just US$19 a month!

Related Reads:

• Empirical Research: A Comprehensive Guide for Academics 
• How to Write a Scientific Paper in 10 Steps 
• How Long Should a Chapter Be?
• How to Use Paperpal to Generate Emails & Cover Letters?

6 Tips for Post-Doc Researchers to Take Their Career to the Next Level

Self-plagiarism in research: what it is and how to avoid it, you may also like, how to write a high-quality conference paper, how paperpal’s research feature helps you develop and..., how paperpal is enhancing academic productivity and accelerating..., how to write a successful book chapter for..., academic editing: how to self-edit academic text with..., 4 ways paperpal encourages responsible writing with ai, what are scholarly sources and where can you..., how to write a hypothesis types and examples , measuring academic success: definition & strategies for excellence, what is academic writing: tips for students.

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals
• Explore content
• About the journal
• Publish with us
• Sign up for alerts
• CAREER FEATURE
• 04 December 2020
• Correction 09 December 2020

How to write a superb literature review

Andy Tay is a freelance writer based in Singapore.

You can also search for this author in PubMed   Google Scholar

Literature reviews are important resources for scientists. They provide historical context for a field while offering opinions on its future trajectory. Creating them can provide inspiration for one’s own research, as well as some practice in writing. But few scientists are trained in how to write a review — or in what constitutes an excellent one. Even picking the appropriate software to use can be an involved decision (see ‘Tools and techniques’). So Nature asked editors and working scientists with well-cited reviews for their tips.

Access options

Access Nature and 54 other Nature Portfolio journals

Get Nature+, our best-value online-access subscription

24,99 € / 30 days

cancel any time

Subscribe to this journal

Receive 51 print issues and online access

185,98 € per year

only 3,65 € per issue

Rent or buy this article

Prices vary by article type

Prices may be subject to local taxes which are calculated during checkout

doi: https://doi.org/10.1038/d41586-020-03422-x

Interviews have been edited for length and clarity.

Updates & Corrections

Correction 09 December 2020 : An earlier version of the tables in this article included some incorrect details about the programs Zotero, Endnote and Manubot. These have now been corrected.

Hsing, I.-M., Xu, Y. & Zhao, W. Electroanalysis 19 , 755–768 (2007).

Article   Google Scholar  

Ledesma, H. A. et al. Nature Nanotechnol. 14 , 645–657 (2019).

Article   PubMed   Google Scholar  

Brahlek, M., Koirala, N., Bansal, N. & Oh, S. Solid State Commun. 215–216 , 54–62 (2015).

Choi, Y. & Lee, S. Y. Nature Rev. Chem . https://doi.org/10.1038/s41570-020-00221-w (2020).

Download references

Related Articles

• Research management

I’m worried I’ve been contacted by a predatory publisher — how do I find out?

Career Feature 15 MAY 24

How I fled bombed Aleppo to continue my career in science

Career Feature 08 MAY 24

Illuminating ‘the ugly side of science’: fresh incentives for reporting negative results

US halts funding to controversial virus-hunting group: what researchers think

News 16 MAY 24

Japan can embrace open science — but flexible approaches are key

Correspondence 07 MAY 24

US funders to tighten oversight of controversial ‘gain of function’ research

News 07 MAY 24

Mount Etna’s spectacular smoke rings and more — April’s best science images

News 03 MAY 24

Postdoc in CRISPR Meta-Analytics and AI for Therapeutic Target Discovery and Priotisation (OT Grant)

APPLICATION CLOSING DATE: 14/06/2024 Human Technopole (HT) is a new interdisciplinary life science research institute created and supported by the...

Human Technopole

Research Associate - Metabolism

Houston, Texas (US)

Baylor College of Medicine (BCM)

Postdoc Fellowships

Train with world-renowned cancer researchers at NIH? Consider joining the Center for Cancer Research (CCR) at the National Cancer Institute

Bethesda, Maryland

NIH National Cancer Institute (NCI)

Faculty Recruitment, Westlake University School of Medicine

Faculty positions are open at four distinct ranks: Assistant Professor, Associate Professor, Full Professor, and Chair Professor.

Hangzhou, Zhejiang, China

Westlake University

PhD/master's Candidate

PhD/master's Candidate    Graduate School of Frontier Science Initiative, Kanazawa University is seeking candidates for PhD and master's students i...

Kanazawa University

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

Reference management. Clean and simple.

Literature review

How to write a literature review in 6 steps

How do you write a good literature review? This step-by-step guide on how to write an excellent literature review covers all aspects of planning and writing literature reviews for academic papers and theses.

How to write a systematic literature review [9 steps]

How do you write a systematic literature review? What types of systematic literature reviews exist and where do you use them? Learn everything you need to know about a systematic literature review in this guide

What is a literature review? [with examples]

Not sure what a literature review is? This guide covers the definition, purpose, and format of a literature review.

• UConn Library
• Literature Review: The What, Why and How-to Guide
• Introduction

Literature Review: The What, Why and How-to Guide — Introduction

• Getting Started
• How to Pick a Topic
• Strategies to Find Sources
• Evaluating Sources & Lit. Reviews
• Tips for Writing Literature Reviews
• Writing Literature Review: Useful Sites
• Citation Resources
• Other Academic Writings

What are Literature Reviews?

So, what is a literature review? "A literature review is an account of what has been published on a topic by accredited scholars and researchers. In writing the literature review, your purpose is to convey to your reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. As a piece of writing, the literature review must be defined by a guiding concept (e.g., your research objective, the problem or issue you are discussing, or your argumentative thesis). It is not just a descriptive list of the material available, or a set of summaries." Taylor, D.  The literature review: A few tips on conducting it . University of Toronto Health Sciences Writing Centre.

Goals of Literature Reviews

What are the goals of creating a Literature Review?  A literature could be written to accomplish different aims:

• To develop a theory or evaluate an existing theory
• To summarize the historical or existing state of a research topic
• Identify a problem in a field of research 

Baumeister, R. F., & Leary, M. R. (1997). Writing narrative literature reviews .  Review of General Psychology , 1 (3), 311-320.

What kinds of sources require a Literature Review?

• A research paper assigned in a course
• A thesis or dissertation
• A grant proposal
• An article intended for publication in a journal

All these instances require you to collect what has been written about your research topic so that you can demonstrate how your own research sheds new light on the topic.

Types of Literature Reviews

What kinds of literature reviews are written?

Narrative review: The purpose of this type of review is to describe the current state of the research on a specific topic/research and to offer a critical analysis of the literature reviewed. Studies are grouped by research/theoretical categories, and themes and trends, strengths and weakness, and gaps are identified. The review ends with a conclusion section which summarizes the findings regarding the state of the research of the specific study, the gaps identify and if applicable, explains how the author's research will address gaps identify in the review and expand the knowledge on the topic reviewed.

• Example : Predictors and Outcomes of U.S. Quality Maternity Leave: A Review and Conceptual Framework:  10.1177/08948453211037398  

Systematic review : "The authors of a systematic review use a specific procedure to search the research literature, select the studies to include in their review, and critically evaluate the studies they find." (p. 139). Nelson, L. K. (2013). Research in Communication Sciences and Disorders . Plural Publishing.

• Example : The effect of leave policies on increasing fertility: a systematic review:  10.1057/s41599-022-01270-w

Meta-analysis : "Meta-analysis is a method of reviewing research findings in a quantitative fashion by transforming the data from individual studies into what is called an effect size and then pooling and analyzing this information. The basic goal in meta-analysis is to explain why different outcomes have occurred in different studies." (p. 197). Roberts, M. C., & Ilardi, S. S. (2003). Handbook of Research Methods in Clinical Psychology . Blackwell Publishing.

• Example : Employment Instability and Fertility in Europe: A Meta-Analysis:  10.1215/00703370-9164737

Meta-synthesis : "Qualitative meta-synthesis is a type of qualitative study that uses as data the findings from other qualitative studies linked by the same or related topic." (p.312). Zimmer, L. (2006). Qualitative meta-synthesis: A question of dialoguing with texts .  Journal of Advanced Nursing , 53 (3), 311-318.

• Example : Women’s perspectives on career successes and barriers: A qualitative meta-synthesis:  10.1177/05390184221113735

Literature Reviews in the Health Sciences

• UConn Health subject guide on systematic reviews Explanation of the different review types used in health sciences literature as well as tools to help you find the right review type
• << Previous: Getting Started
• Next: How to Pick a Topic >>
• Last Updated: Sep 21, 2022 2:16 PM
• URL: https://guides.lib.uconn.edu/literaturereview

Harvey Cushing/John Hay Whitney Medical Library

• Collections
• Research Help

YSN Doctoral Programs: Steps in Conducting a Literature Review

• Biomedical Databases
• Global (Public Health) Databases
• Soc. Sci., History, and Law Databases
• Grey Literature
• Trials Registers
• Data and Statistics
• Public Policy
• Google Tips
• Recommended Books
• Steps in Conducting a Literature Review

What is a literature review?

A literature review is an integrated analysis -- not just a summary-- of scholarly writings and other relevant evidence related directly to your research question.  That is, it represents a synthesis of the evidence that provides background information on your topic and shows a association between the evidence and your research question.

A literature review may be a stand alone work or the introduction to a larger research paper, depending on the assignment.  Rely heavily on the guidelines your instructor has given you.

Why is it important?

A literature review is important because it:

• Explains the background of research on a topic.
• Demonstrates why a topic is significant to a subject area.
• Discovers relationships between research studies/ideas.
• Identifies major themes, concepts, and researchers on a topic.
• Identifies critical gaps and points of disagreement.
• Discusses further research questions that logically come out of the previous studies.

APA7 Style resources

APA Style Blog - for those harder to find answers

1. Choose a topic. Define your research question.

Your literature review should be guided by your central research question.  The literature represents background and research developments related to a specific research question, interpreted and analyzed by you in a synthesized way.

• Make sure your research question is not too broad or too narrow.  Is it manageable?
• Begin writing down terms that are related to your question. These will be useful for searches later.
• If you have the opportunity, discuss your topic with your professor and your class mates.

2. Decide on the scope of your review

How many studies do you need to look at? How comprehensive should it be? How many years should it cover? 

• This may depend on your assignment.  How many sources does the assignment require?

3. Select the databases you will use to conduct your searches.

Make a list of the databases you will search. 

Where to find databases:

• use the tabs on this guide
• Find other databases in the Nursing Information Resources web page
• More on the Medical Library web page
• ... and more on the Yale University Library web page

4. Conduct your searches to find the evidence. Keep track of your searches.

• Use the key words in your question, as well as synonyms for those words, as terms in your search. Use the database tutorials for help.
• Save the searches in the databases. This saves time when you want to redo, or modify, the searches. It is also helpful to use as a guide is the searches are not finding any useful results.
• Review the abstracts of research studies carefully. This will save you time.
• Use the bibliographies and references of research studies you find to locate others.
• Check with your professor, or a subject expert in the field, if you are missing any key works in the field.
• Ask your librarian for help at any time.
• Use a citation manager, such as EndNote as the repository for your citations. See the EndNote tutorials for help.

Review the literature

Some questions to help you analyze the research:

• What was the research question of the study you are reviewing? What were the authors trying to discover?
• Was the research funded by a source that could influence the findings?
• What were the research methodologies? Analyze its literature review, the samples and variables used, the results, and the conclusions.
• Does the research seem to be complete? Could it have been conducted more soundly? What further questions does it raise?
• If there are conflicting studies, why do you think that is?
• How are the authors viewed in the field? Has this study been cited? If so, how has it been analyzed?

Tips: 

• Review the abstracts carefully.  
• Keep careful notes so that you may track your thought processes during the research process.
• Create a matrix of the studies for easy analysis, and synthesis, across all of the studies.
• << Previous: Recommended Books
• Last Updated: Jan 4, 2024 10:52 AM
• URL: https://guides.library.yale.edu/YSNDoctoral

How To Structure Your Literature Review

3 options to help structure your chapter.

By: Amy Rommelspacher (PhD) | Reviewer: Dr Eunice Rautenbach | November 2020 (Updated May 2023)

Writing the literature review chapter can seem pretty daunting when you’re piecing together your dissertation or thesis. As  we’ve discussed before , a good literature review needs to achieve a few very important objectives – it should:

• Demonstrate your knowledge of the research topic
• Identify the gaps in the literature and show how your research links to these
• Provide the foundation for your conceptual framework (if you have one)
• Inform your own  methodology and research design

To achieve this, your literature review needs a well-thought-out structure . Get the structure of your literature review chapter wrong and you’ll struggle to achieve these objectives. Don’t worry though – in this post, we’ll look at how to structure your literature review for maximum impact (and marks!).

But wait – is this the right time?

Deciding on the structure of your literature review should come towards the end of the literature review process – after you have collected and digested the literature, but before you start writing the chapter. 

In other words, you need to first develop a rich understanding of the literature before you even attempt to map out a structure. There’s no use trying to develop a structure before you’ve fully wrapped your head around the existing research.

Equally importantly, you need to have a structure in place before you start writing , or your literature review will most likely end up a rambling, disjointed mess. 

Importantly, don’t feel that once you’ve defined a structure you can’t iterate on it. It’s perfectly natural to adjust as you engage in the writing process. As we’ve discussed before , writing is a way of developing your thinking, so it’s quite common for your thinking to change – and therefore, for your chapter structure to change – as you write. 

Need a helping hand?

Like any other chapter in your thesis or dissertation, your literature review needs to have a clear, logical structure. At a minimum, it should have three essential components – an  introduction , a  body   and a  conclusion . 

Let’s take a closer look at each of these.

1: The Introduction Section

Just like any good introduction, the introduction section of your literature review should introduce the purpose and layout (organisation) of the chapter. In other words, your introduction needs to give the reader a taste of what’s to come, and how you’re going to lay that out. Essentially, you should provide the reader with a high-level roadmap of your chapter to give them a taste of the journey that lies ahead.

Here’s an example of the layout visualised in a literature review introduction:

Your introduction should also outline your topic (including any tricky terminology or jargon) and provide an explanation of the scope of your literature review – in other words, what you  will   and  won’t   be covering (the delimitations ). This helps ringfence your review and achieve a clear focus . The clearer and narrower your focus, the deeper you can dive into the topic (which is typically where the magic lies). 

Depending on the nature of your project, you could also present your stance or point of view at this stage. In other words, after grappling with the literature you’ll have an opinion about what the trends and concerns are in the field as well as what’s lacking. The introduction section can then present these ideas so that it is clear to examiners that you’re aware of how your research connects with existing knowledge .

2: The Body Section

The body of your literature review is the centre of your work. This is where you’ll present, analyse, evaluate and synthesise the existing research. In other words, this is where you’re going to earn (or lose) the most marks. Therefore, it’s important to carefully think about how you will organise your discussion to present it in a clear way. 

The body of your literature review should do just as the description of this chapter suggests. It should “review” the literature – in other words, identify, analyse, and synthesise it. So, when thinking about structuring your literature review, you need to think about which structural approach will provide the best “review” for your specific type of research and objectives (we’ll get to this shortly).

There are (broadly speaking)  three options  for organising your literature review.

Option 1: Chronological (according to date)

Organising the literature chronologically is one of the simplest ways to structure your literature review. You start with what was published first and work your way through the literature until you reach the work published most recently. Pretty straightforward.

The benefit of this option is that it makes it easy to discuss the developments and debates in the field as they emerged over time. Organising your literature chronologically also allows you to highlight how specific articles or pieces of work might have changed the course of the field – in other words, which research has had the most impact . Therefore, this approach is very useful when your research is aimed at understanding how the topic has unfolded over time and is often used by scholars in the field of history. That said, this approach can be utilised by anyone that wants to explore change over time .

For example , if a student of politics is investigating how the understanding of democracy has evolved over time, they could use the chronological approach to provide a narrative that demonstrates how this understanding has changed through the ages.

Here are some questions you can ask yourself to help you structure your literature review chronologically.

• What is the earliest literature published relating to this topic?
• How has the field changed over time? Why?
• What are the most recent discoveries/theories?

In some ways, chronology plays a part whichever way you decide to structure your literature review, because you will always, to a certain extent, be analysing how the literature has developed. However, with the chronological approach, the emphasis is very firmly on how the discussion has evolved over time , as opposed to how all the literature links together (which we’ll discuss next ).

Option 2: Thematic (grouped by theme)

The thematic approach to structuring a literature review means organising your literature by theme or category – for example, by independent variables (i.e. factors that have an impact on a specific outcome).

As you’ve been collecting and synthesising literature , you’ll likely have started seeing some themes or patterns emerging. You can then use these themes or patterns as a structure for your body discussion. The thematic approach is the most common approach and is useful for structuring literature reviews in most fields.

For example, if you were researching which factors contributed towards people trusting an organisation, you might find themes such as consumers’ perceptions of an organisation’s competence, benevolence and integrity. Structuring your literature review thematically would mean structuring your literature review’s body section to discuss each of these themes, one section at a time.

Here are some questions to ask yourself when structuring your literature review by themes:

• Are there any patterns that have come to light in the literature?
• What are the central themes and categories used by the researchers?
• Do I have enough evidence of these themes?

PS – you can see an example of a thematically structured literature review in our literature review sample walkthrough video here.

Option 3: Methodological

The methodological option is a way of structuring your literature review by the research methodologies used . In other words, organising your discussion based on the angle from which each piece of research was approached – for example, qualitative , quantitative or mixed  methodologies.

Structuring your literature review by methodology can be useful if you are drawing research from a variety of disciplines and are critiquing different methodologies. The point of this approach is to question  how  existing research has been conducted, as opposed to  what  the conclusions and/or findings the research were.

For example, a sociologist might centre their research around critiquing specific fieldwork practices. Their literature review will then be a summary of the fieldwork methodologies used by different studies.

Here are some questions you can ask yourself when structuring your literature review according to methodology:

• Which methodologies have been utilised in this field?
• Which methodology is the most popular (and why)?
• What are the strengths and weaknesses of the various methodologies?
• How can the existing methodologies inform my own methodology?

3: The Conclusion Section

Once you’ve completed the body section of your literature review using one of the structural approaches we discussed above, you’ll need to “wrap up” your literature review and pull all the pieces together to set the direction for the rest of your dissertation or thesis.

The conclusion is where you’ll present the key findings of your literature review. In this section, you should emphasise the research that is especially important to your research questions and highlight the gaps that exist in the literature. Based on this, you need to make it clear what you will add to the literature – in other words, justify your own research by showing how it will help fill one or more of the gaps you just identified.

Last but not least, if it’s your intention to develop a conceptual framework for your dissertation or thesis, the conclusion section is a good place to present this.

Example: Thematically Structured Review

In the video below, we unpack a literature review chapter so that you can see an example of a thematically structure review in practice.

Let’s Recap

In this article, we’ve  discussed how to structure your literature review for maximum impact. Here’s a quick recap of what  you need to keep in mind when deciding on your literature review structure:

• Just like other chapters, your literature review needs a clear introduction , body and conclusion .
• The introduction section should provide an overview of what you will discuss in your literature review.
• The body section of your literature review can be organised by chronology , theme or methodology . The right structural approach depends on what you’re trying to achieve with your research.
• The conclusion section should draw together the key findings of your literature review and link them to your research questions.

If you’re ready to get started, be sure to download our free literature review template to fast-track your chapter outline.

Psst… there’s more!

This post is an extract from our bestselling short course, Literature Review Bootcamp . If you want to work smart, you don't want to miss this .

You Might Also Like:

27 Comments

Great work. This is exactly what I was looking for and helps a lot together with your previous post on literature review. One last thing is missing: a link to a great literature chapter of an journal article (maybe with comments of the different sections in this review chapter). Do you know any great literature review chapters?

I agree with you Marin… A great piece

I agree with Marin. This would be quite helpful if you annotate a nicely structured literature from previously published research articles.

Awesome article for my research.

I thank you immensely for this wonderful guide

It is indeed thought and supportive work for the futurist researcher and students

Very educative and good time to get guide. Thank you

Great work, very insightful. Thank you.

Thanks for this wonderful presentation. My question is that do I put all the variables into a single conceptual framework or each hypothesis will have it own conceptual framework?

Thank you very much, very helpful

This is very educative and precise . Thank you very much for dropping this kind of write up .

Pheeww, so damn helpful, thank you for this informative piece.

I’m doing a research project topic ; stool analysis for parasitic worm (enteric) worm, how do I structure it, thanks.

comprehensive explanation. Help us by pasting the URL of some good “literature review” for better understanding.

great piece. thanks for the awesome explanation. it is really worth sharing. I have a little question, if anyone can help me out, which of the options in the body of literature can be best fit if you are writing an architectural thesis that deals with design?

I am doing a research on nanofluids how can l structure it?

Beautifully clear.nThank you!

Lucid! Thankyou!

Brilliant work, well understood, many thanks

I like how this was so clear with simple language 😊😊 thank you so much 😊 for these information 😊

Insightful. I was struggling to come up with a sensible literature review but this has been really helpful. Thank you!

You have given thought-provoking information about the review of the literature.

Thank you. It has made my own research better and to impart your work to students I teach

I learnt a lot from this teaching. It’s a great piece.

I am doing research on EFL teacher motivation for his/her job. How Can I structure it? Is there any detailed template, additional to this?

You are so cool! I do not think I’ve read through something like this before. So nice to find somebody with some genuine thoughts on this issue. Seriously.. thank you for starting this up. This site is one thing that is required on the internet, someone with a little originality!

I’m asked to do conceptual, theoretical and empirical literature, and i just don’t know how to structure it

Submit a Comment Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

• Print Friendly

How to Write a Literature Review

What is a literature review.

• What Is the Literature
• Writing the Review

A literature review is much more than an annotated bibliography or a list of separate reviews of articles and books. It is a critical, analytical summary and synthesis of the current knowledge of a topic. Thus it should compare and relate different theories, findings, etc, rather than just summarize them individually. In addition, it should have a particular focus or theme to organize the review. It does not have to be an exhaustive account of everything published on the topic, but it should discuss all the significant academic literature and other relevant sources important for that focus.

This is meant to be a general guide to writing a literature review: ways to structure one, what to include, how it supplements other research. For more specific help on writing a review, and especially for help on finding the literature to review, sign up for a Personal Research Session .

The specific organization of a literature review depends on the type and purpose of the review, as well as on the specific field or topic being reviewed. But in general, it is a relatively brief but thorough exploration of past and current work on a topic. Rather than a chronological listing of previous work, though, literature reviews are usually organized thematically, such as different theoretical approaches, methodologies, or specific issues or concepts involved in the topic. A thematic organization makes it much easier to examine contrasting perspectives, theoretical approaches, methodologies, findings, etc, and to analyze the strengths and weaknesses of, and point out any gaps in, previous research. And this is the heart of what a literature review is about. A literature review may offer new interpretations, theoretical approaches, or other ideas; if it is part of a research proposal or report it should demonstrate the relationship of the proposed or reported research to others' work; but whatever else it does, it must provide a critical overview of the current state of research efforts. 

Literature reviews are common and very important in the sciences and social sciences. They are less common and have a less important role in the humanities, but they do have a place, especially stand-alone reviews.

Types of Literature Reviews

There are different types of literature reviews, and different purposes for writing a review, but the most common are:

• Stand-alone literature review articles . These provide an overview and analysis of the current state of research on a topic or question. The goal is to evaluate and compare previous research on a topic to provide an analysis of what is currently known, and also to reveal controversies, weaknesses, and gaps in current work, thus pointing to directions for future research. You can find examples published in any number of academic journals, but there is a series of Annual Reviews of *Subject* which are specifically devoted to literature review articles. Writing a stand-alone review is often an effective way to get a good handle on a topic and to develop ideas for your own research program. For example, contrasting theoretical approaches or conflicting interpretations of findings can be the basis of your research project: can you find evidence supporting one interpretation against another, or can you propose an alternative interpretation that overcomes their limitations?
• Part of a research proposal . This could be a proposal for a PhD dissertation, a senior thesis, or a class project. It could also be a submission for a grant. The literature review, by pointing out the current issues and questions concerning a topic, is a crucial part of demonstrating how your proposed research will contribute to the field, and thus of convincing your thesis committee to allow you to pursue the topic of your interest or a funding agency to pay for your research efforts.
• Part of a research report . When you finish your research and write your thesis or paper to present your findings, it should include a literature review to provide the context to which your work is a contribution. Your report, in addition to detailing the methods, results, etc. of your research, should show how your work relates to others' work.

A literature review for a research report is often a revision of the review for a research proposal, which can be a revision of a stand-alone review. Each revision should be a fairly extensive revision. With the increased knowledge of and experience in the topic as you proceed, your understanding of the topic will increase. Thus, you will be in a better position to analyze and critique the literature. In addition, your focus will change as you proceed in your research. Some areas of the literature you initially reviewed will be marginal or irrelevant for your eventual research, and you will need to explore other areas more thoroughly. 

Examples of Literature Reviews

See the series of Annual Reviews of *Subject* which are specifically devoted to literature review articles to find many examples of stand-alone literature reviews in the biomedical, physical, and social sciences. 

Research report articles vary in how they are organized, but a common general structure is to have sections such as:

• Abstract - Brief summary of the contents of the article
• Introduction - A explanation of the purpose of the study, a statement of the research question(s) the study intends to address
• Literature review - A critical assessment of the work done so far on this topic, to show how the current study relates to what has already been done
• Methods - How the study was carried out (e.g. instruments or equipment, procedures, methods to gather and analyze data)
• Results - What was found in the course of the study
• Discussion - What do the results mean
• Conclusion - State the conclusions and implications of the results, and discuss how it relates to the work reviewed in the literature review; also, point to directions for further work in the area

Here are some articles that illustrate variations on this theme. There is no need to read the entire articles (unless the contents interest you); just quickly browse through to see the sections, and see how each section is introduced and what is contained in them.

The Determinants of Undergraduate Grade Point Average: The Relative Importance of Family Background, High School Resources, and Peer Group Effects , in The Journal of Human Resources , v. 34 no. 2 (Spring 1999), p. 268-293.

This article has a standard breakdown of sections:

• Introduction
• Literature Review
• Some discussion sections

First Encounters of the Bureaucratic Kind: Early Freshman Experiences with a Campus Bureaucracy , in The Journal of Higher Education , v. 67 no. 6 (Nov-Dec 1996), p. 660-691.

This one does not have a section specifically labeled as a "literature review" or "review of the literature," but the first few sections cite a long list of other sources discussing previous research in the area before the authors present their own study they are reporting.

• Next: What Is the Literature >>
• Last Updated: Jan 11, 2024 9:48 AM
• URL: https://libguides.wesleyan.edu/litreview

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• PLoS Comput Biol
• v.9(7); 2013 Jul

Ten Simple Rules for Writing a Literature Review

Marco pautasso.

1 Centre for Functional and Evolutionary Ecology (CEFE), CNRS, Montpellier, France

2 Centre for Biodiversity Synthesis and Analysis (CESAB), FRB, Aix-en-Provence, France

Literature reviews are in great demand in most scientific fields. Their need stems from the ever-increasing output of scientific publications [1] . For example, compared to 1991, in 2008 three, eight, and forty times more papers were indexed in Web of Science on malaria, obesity, and biodiversity, respectively [2] . Given such mountains of papers, scientists cannot be expected to examine in detail every single new paper relevant to their interests [3] . Thus, it is both advantageous and necessary to rely on regular summaries of the recent literature. Although recognition for scientists mainly comes from primary research, timely literature reviews can lead to new synthetic insights and are often widely read [4] . For such summaries to be useful, however, they need to be compiled in a professional way [5] .

When starting from scratch, reviewing the literature can require a titanic amount of work. That is why researchers who have spent their career working on a certain research issue are in a perfect position to review that literature. Some graduate schools are now offering courses in reviewing the literature, given that most research students start their project by producing an overview of what has already been done on their research issue [6] . However, it is likely that most scientists have not thought in detail about how to approach and carry out a literature review.

Reviewing the literature requires the ability to juggle multiple tasks, from finding and evaluating relevant material to synthesising information from various sources, from critical thinking to paraphrasing, evaluating, and citation skills [7] . In this contribution, I share ten simple rules I learned working on about 25 literature reviews as a PhD and postdoctoral student. Ideas and insights also come from discussions with coauthors and colleagues, as well as feedback from reviewers and editors.

Rule 1: Define a Topic and Audience

How to choose which topic to review? There are so many issues in contemporary science that you could spend a lifetime of attending conferences and reading the literature just pondering what to review. On the one hand, if you take several years to choose, several other people may have had the same idea in the meantime. On the other hand, only a well-considered topic is likely to lead to a brilliant literature review [8] . The topic must at least be:

• interesting to you (ideally, you should have come across a series of recent papers related to your line of work that call for a critical summary),
• an important aspect of the field (so that many readers will be interested in the review and there will be enough material to write it), and
• a well-defined issue (otherwise you could potentially include thousands of publications, which would make the review unhelpful).

Ideas for potential reviews may come from papers providing lists of key research questions to be answered [9] , but also from serendipitous moments during desultory reading and discussions. In addition to choosing your topic, you should also select a target audience. In many cases, the topic (e.g., web services in computational biology) will automatically define an audience (e.g., computational biologists), but that same topic may also be of interest to neighbouring fields (e.g., computer science, biology, etc.).

Rule 2: Search and Re-search the Literature

After having chosen your topic and audience, start by checking the literature and downloading relevant papers. Five pieces of advice here:

• keep track of the search items you use (so that your search can be replicated [10] ),
• keep a list of papers whose pdfs you cannot access immediately (so as to retrieve them later with alternative strategies),
• use a paper management system (e.g., Mendeley, Papers, Qiqqa, Sente),
• define early in the process some criteria for exclusion of irrelevant papers (these criteria can then be described in the review to help define its scope), and
• do not just look for research papers in the area you wish to review, but also seek previous reviews.

The chances are high that someone will already have published a literature review ( Figure 1 ), if not exactly on the issue you are planning to tackle, at least on a related topic. If there are already a few or several reviews of the literature on your issue, my advice is not to give up, but to carry on with your own literature review,

The bottom-right situation (many literature reviews but few research papers) is not just a theoretical situation; it applies, for example, to the study of the impacts of climate change on plant diseases, where there appear to be more literature reviews than research studies [33] .

• discussing in your review the approaches, limitations, and conclusions of past reviews,
• trying to find a new angle that has not been covered adequately in the previous reviews, and
• incorporating new material that has inevitably accumulated since their appearance.

When searching the literature for pertinent papers and reviews, the usual rules apply:

• be thorough,
• use different keywords and database sources (e.g., DBLP, Google Scholar, ISI Proceedings, JSTOR Search, Medline, Scopus, Web of Science), and
• look at who has cited past relevant papers and book chapters.

Rule 3: Take Notes While Reading

If you read the papers first, and only afterwards start writing the review, you will need a very good memory to remember who wrote what, and what your impressions and associations were while reading each single paper. My advice is, while reading, to start writing down interesting pieces of information, insights about how to organize the review, and thoughts on what to write. This way, by the time you have read the literature you selected, you will already have a rough draft of the review.

Of course, this draft will still need much rewriting, restructuring, and rethinking to obtain a text with a coherent argument [11] , but you will have avoided the danger posed by staring at a blank document. Be careful when taking notes to use quotation marks if you are provisionally copying verbatim from the literature. It is advisable then to reformulate such quotes with your own words in the final draft. It is important to be careful in noting the references already at this stage, so as to avoid misattributions. Using referencing software from the very beginning of your endeavour will save you time.

Rule 4: Choose the Type of Review You Wish to Write

After having taken notes while reading the literature, you will have a rough idea of the amount of material available for the review. This is probably a good time to decide whether to go for a mini- or a full review. Some journals are now favouring the publication of rather short reviews focusing on the last few years, with a limit on the number of words and citations. A mini-review is not necessarily a minor review: it may well attract more attention from busy readers, although it will inevitably simplify some issues and leave out some relevant material due to space limitations. A full review will have the advantage of more freedom to cover in detail the complexities of a particular scientific development, but may then be left in the pile of the very important papers “to be read” by readers with little time to spare for major monographs.

There is probably a continuum between mini- and full reviews. The same point applies to the dichotomy of descriptive vs. integrative reviews. While descriptive reviews focus on the methodology, findings, and interpretation of each reviewed study, integrative reviews attempt to find common ideas and concepts from the reviewed material [12] . A similar distinction exists between narrative and systematic reviews: while narrative reviews are qualitative, systematic reviews attempt to test a hypothesis based on the published evidence, which is gathered using a predefined protocol to reduce bias [13] , [14] . When systematic reviews analyse quantitative results in a quantitative way, they become meta-analyses. The choice between different review types will have to be made on a case-by-case basis, depending not just on the nature of the material found and the preferences of the target journal(s), but also on the time available to write the review and the number of coauthors [15] .

Rule 5: Keep the Review Focused, but Make It of Broad Interest

Whether your plan is to write a mini- or a full review, it is good advice to keep it focused 16 , 17 . Including material just for the sake of it can easily lead to reviews that are trying to do too many things at once. The need to keep a review focused can be problematic for interdisciplinary reviews, where the aim is to bridge the gap between fields [18] . If you are writing a review on, for example, how epidemiological approaches are used in modelling the spread of ideas, you may be inclined to include material from both parent fields, epidemiology and the study of cultural diffusion. This may be necessary to some extent, but in this case a focused review would only deal in detail with those studies at the interface between epidemiology and the spread of ideas.

While focus is an important feature of a successful review, this requirement has to be balanced with the need to make the review relevant to a broad audience. This square may be circled by discussing the wider implications of the reviewed topic for other disciplines.

Rule 6: Be Critical and Consistent

Reviewing the literature is not stamp collecting. A good review does not just summarize the literature, but discusses it critically, identifies methodological problems, and points out research gaps [19] . After having read a review of the literature, a reader should have a rough idea of:

• the major achievements in the reviewed field,
• the main areas of debate, and
• the outstanding research questions.

It is challenging to achieve a successful review on all these fronts. A solution can be to involve a set of complementary coauthors: some people are excellent at mapping what has been achieved, some others are very good at identifying dark clouds on the horizon, and some have instead a knack at predicting where solutions are going to come from. If your journal club has exactly this sort of team, then you should definitely write a review of the literature! In addition to critical thinking, a literature review needs consistency, for example in the choice of passive vs. active voice and present vs. past tense.

Rule 7: Find a Logical Structure

Like a well-baked cake, a good review has a number of telling features: it is worth the reader's time, timely, systematic, well written, focused, and critical. It also needs a good structure. With reviews, the usual subdivision of research papers into introduction, methods, results, and discussion does not work or is rarely used. However, a general introduction of the context and, toward the end, a recapitulation of the main points covered and take-home messages make sense also in the case of reviews. For systematic reviews, there is a trend towards including information about how the literature was searched (database, keywords, time limits) [20] .

How can you organize the flow of the main body of the review so that the reader will be drawn into and guided through it? It is generally helpful to draw a conceptual scheme of the review, e.g., with mind-mapping techniques. Such diagrams can help recognize a logical way to order and link the various sections of a review [21] . This is the case not just at the writing stage, but also for readers if the diagram is included in the review as a figure. A careful selection of diagrams and figures relevant to the reviewed topic can be very helpful to structure the text too [22] .

Rule 8: Make Use of Feedback

Reviews of the literature are normally peer-reviewed in the same way as research papers, and rightly so [23] . As a rule, incorporating feedback from reviewers greatly helps improve a review draft. Having read the review with a fresh mind, reviewers may spot inaccuracies, inconsistencies, and ambiguities that had not been noticed by the writers due to rereading the typescript too many times. It is however advisable to reread the draft one more time before submission, as a last-minute correction of typos, leaps, and muddled sentences may enable the reviewers to focus on providing advice on the content rather than the form.

Feedback is vital to writing a good review, and should be sought from a variety of colleagues, so as to obtain a diversity of views on the draft. This may lead in some cases to conflicting views on the merits of the paper, and on how to improve it, but such a situation is better than the absence of feedback. A diversity of feedback perspectives on a literature review can help identify where the consensus view stands in the landscape of the current scientific understanding of an issue [24] .

Rule 9: Include Your Own Relevant Research, but Be Objective

In many cases, reviewers of the literature will have published studies relevant to the review they are writing. This could create a conflict of interest: how can reviewers report objectively on their own work [25] ? Some scientists may be overly enthusiastic about what they have published, and thus risk giving too much importance to their own findings in the review. However, bias could also occur in the other direction: some scientists may be unduly dismissive of their own achievements, so that they will tend to downplay their contribution (if any) to a field when reviewing it.

In general, a review of the literature should neither be a public relations brochure nor an exercise in competitive self-denial. If a reviewer is up to the job of producing a well-organized and methodical review, which flows well and provides a service to the readership, then it should be possible to be objective in reviewing one's own relevant findings. In reviews written by multiple authors, this may be achieved by assigning the review of the results of a coauthor to different coauthors.

Rule 10: Be Up-to-Date, but Do Not Forget Older Studies

Given the progressive acceleration in the publication of scientific papers, today's reviews of the literature need awareness not just of the overall direction and achievements of a field of inquiry, but also of the latest studies, so as not to become out-of-date before they have been published. Ideally, a literature review should not identify as a major research gap an issue that has just been addressed in a series of papers in press (the same applies, of course, to older, overlooked studies (“sleeping beauties” [26] )). This implies that literature reviewers would do well to keep an eye on electronic lists of papers in press, given that it can take months before these appear in scientific databases. Some reviews declare that they have scanned the literature up to a certain point in time, but given that peer review can be a rather lengthy process, a full search for newly appeared literature at the revision stage may be worthwhile. Assessing the contribution of papers that have just appeared is particularly challenging, because there is little perspective with which to gauge their significance and impact on further research and society.

Inevitably, new papers on the reviewed topic (including independently written literature reviews) will appear from all quarters after the review has been published, so that there may soon be the need for an updated review. But this is the nature of science [27] – [32] . I wish everybody good luck with writing a review of the literature.

Acknowledgments

Many thanks to M. Barbosa, K. Dehnen-Schmutz, T. Döring, D. Fontaneto, M. Garbelotto, O. Holdenrieder, M. Jeger, D. Lonsdale, A. MacLeod, P. Mills, M. Moslonka-Lefebvre, G. Stancanelli, P. Weisberg, and X. Xu for insights and discussions, and to P. Bourne, T. Matoni, and D. Smith for helpful comments on a previous draft.

Funding Statement

This work was funded by the French Foundation for Research on Biodiversity (FRB) through its Centre for Synthesis and Analysis of Biodiversity data (CESAB), as part of the NETSEED research project. The funders had no role in the preparation of the manuscript.

• USC Libraries
• Research Guides

Organizing Your Social Sciences Research Paper

• 5. The Literature Review
• Purpose of Guide
• Design Flaws to Avoid
• Independent and Dependent Variables
• Glossary of Research Terms
• Reading Research Effectively
• Narrowing a Topic Idea
• Broadening a Topic Idea
• Extending the Timeliness of a Topic Idea
• Academic Writing Style
• Applying Critical Thinking
• Choosing a Title
• Making an Outline
• Paragraph Development
• Research Process Video Series
• Executive Summary
• The C.A.R.S. Model
• Background Information
• The Research Problem/Question
• Theoretical Framework
• Citation Tracking
• Content Alert Services
• Evaluating Sources
• Primary Sources
• Secondary Sources
• Tiertiary Sources
• Scholarly vs. Popular Publications
• Qualitative Methods
• Quantitative Methods
• Insiderness
• Using Non-Textual Elements
• Limitations of the Study
• Common Grammar Mistakes
• Writing Concisely
• Avoiding Plagiarism
• Footnotes or Endnotes?
• Further Readings
• Generative AI and Writing
• USC Libraries Tutorials and Other Guides
• Bibliography

A literature review surveys prior research published in books, scholarly articles, and any other sources relevant to a particular issue, area of research, or theory, and by so doing, provides a description, summary, and critical evaluation of these works in relation to the research problem being investigated. Literature reviews are designed to provide an overview of sources you have used in researching a particular topic and to demonstrate to your readers how your research fits within existing scholarship about the topic.

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . Fourth edition. Thousand Oaks, CA: SAGE, 2014.

Importance of a Good Literature Review

A literature review may consist of simply a summary of key sources, but in the social sciences, a literature review usually has an organizational pattern and combines both summary and synthesis, often within specific conceptual categories . A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information in a way that informs how you are planning to investigate a research problem. The analytical features of a literature review might:

• Give a new interpretation of old material or combine new with old interpretations,
• Trace the intellectual progression of the field, including major debates,
• Depending on the situation, evaluate the sources and advise the reader on the most pertinent or relevant research, or
• Usually in the conclusion of a literature review, identify where gaps exist in how a problem has been researched to date.

Given this, the purpose of a literature review is to:

• Place each work in the context of its contribution to understanding the research problem being studied.
• Describe the relationship of each work to the others under consideration.
• Identify new ways to interpret prior research.
• Reveal any gaps that exist in the literature.
• Resolve conflicts amongst seemingly contradictory previous studies.
• Identify areas of prior scholarship to prevent duplication of effort.
• Point the way in fulfilling a need for additional research.
• Locate your own research within the context of existing literature [very important].

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper. 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . Los Angeles, CA: SAGE, 2011; Knopf, Jeffrey W. "Doing a Literature Review." PS: Political Science and Politics 39 (January 2006): 127-132; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012.

Types of Literature Reviews

It is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the primary studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally among scholars that become part of the body of epistemological traditions within the field.

In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews. Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are a number of approaches you could adopt depending upon the type of analysis underpinning your study.

Argumentative Review This form examines literature selectively in order to support or refute an argument, deeply embedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to make summary claims of the sort found in systematic reviews [see below].

Integrative Review Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses or research problems. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication. This is the most common form of review in the social sciences.

Historical Review Few things rest in isolation from historical precedent. Historical literature reviews focus on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review A review does not always focus on what someone said [findings], but how they came about saying what they say [method of analysis]. Reviewing methods of analysis provides a framework of understanding at different levels [i.e. those of theory, substantive fields, research approaches, and data collection and analysis techniques], how researchers draw upon a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection, and data analysis. This approach helps highlight ethical issues which you should be aware of and consider as you go through your own study.

Systematic Review This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyze data from the studies that are included in the review. The goal is to deliberately document, critically evaluate, and summarize scientifically all of the research about a clearly defined research problem . Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?" This type of literature review is primarily applied to examining prior research studies in clinical medicine and allied health fields, but it is increasingly being used in the social sciences.

Theoretical Review The purpose of this form is to examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review helps to establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

NOTE : Most often the literature review will incorporate some combination of types. For example, a review that examines literature supporting or refuting an argument, assumption, or philosophical problem related to the research problem will also need to include writing supported by sources that establish the history of these arguments in the literature.

Baumeister, Roy F. and Mark R. Leary. "Writing Narrative Literature Reviews."  Review of General Psychology 1 (September 1997): 311-320; Mark R. Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Kennedy, Mary M. "Defining a Literature." Educational Researcher 36 (April 2007): 139-147; Petticrew, Mark and Helen Roberts. Systematic Reviews in the Social Sciences: A Practical Guide . Malden, MA: Blackwell Publishers, 2006; Torracro, Richard. "Writing Integrative Literature Reviews: Guidelines and Examples." Human Resource Development Review 4 (September 2005): 356-367; Rocco, Tonette S. and Maria S. Plakhotnik. "Literature Reviews, Conceptual Frameworks, and Theoretical Frameworks: Terms, Functions, and Distinctions." Human Ressource Development Review 8 (March 2008): 120-130; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

Structure and Writing Style

I.  Thinking About Your Literature Review

The structure of a literature review should include the following in support of understanding the research problem :

• An overview of the subject, issue, or theory under consideration, along with the objectives of the literature review,
• Division of works under review into themes or categories [e.g. works that support a particular position, those against, and those offering alternative approaches entirely],
• An explanation of how each work is similar to and how it varies from the others,
• Conclusions as to which pieces are best considered in their argument, are most convincing of their opinions, and make the greatest contribution to the understanding and development of their area of research.

The critical evaluation of each work should consider :

• Provenance -- what are the author's credentials? Are the author's arguments supported by evidence [e.g. primary historical material, case studies, narratives, statistics, recent scientific findings]?
• Methodology -- were the techniques used to identify, gather, and analyze the data appropriate to addressing the research problem? Was the sample size appropriate? Were the results effectively interpreted and reported?
• Objectivity -- is the author's perspective even-handed or prejudicial? Is contrary data considered or is certain pertinent information ignored to prove the author's point?
• Persuasiveness -- which of the author's theses are most convincing or least convincing?
• Validity -- are the author's arguments and conclusions convincing? Does the work ultimately contribute in any significant way to an understanding of the subject?

II.  Development of the Literature Review

Four Basic Stages of Writing 1.  Problem formulation -- which topic or field is being examined and what are its component issues? 2.  Literature search -- finding materials relevant to the subject being explored. 3.  Data evaluation -- determining which literature makes a significant contribution to the understanding of the topic. 4.  Analysis and interpretation -- discussing the findings and conclusions of pertinent literature.

Consider the following issues before writing the literature review: Clarify If your assignment is not specific about what form your literature review should take, seek clarification from your professor by asking these questions: 1.  Roughly how many sources would be appropriate to include? 2.  What types of sources should I review (books, journal articles, websites; scholarly versus popular sources)? 3.  Should I summarize, synthesize, or critique sources by discussing a common theme or issue? 4.  Should I evaluate the sources in any way beyond evaluating how they relate to understanding the research problem? 5.  Should I provide subheadings and other background information, such as definitions and/or a history? Find Models Use the exercise of reviewing the literature to examine how authors in your discipline or area of interest have composed their literature review sections. Read them to get a sense of the types of themes you might want to look for in your own research or to identify ways to organize your final review. The bibliography or reference section of sources you've already read, such as required readings in the course syllabus, are also excellent entry points into your own research. Narrow the Topic The narrower your topic, the easier it will be to limit the number of sources you need to read in order to obtain a good survey of relevant resources. Your professor will probably not expect you to read everything that's available about the topic, but you'll make the act of reviewing easier if you first limit scope of the research problem. A good strategy is to begin by searching the USC Libraries Catalog for recent books about the topic and review the table of contents for chapters that focuses on specific issues. You can also review the indexes of books to find references to specific issues that can serve as the focus of your research. For example, a book surveying the history of the Israeli-Palestinian conflict may include a chapter on the role Egypt has played in mediating the conflict, or look in the index for the pages where Egypt is mentioned in the text. Consider Whether Your Sources are Current Some disciplines require that you use information that is as current as possible. This is particularly true in disciplines in medicine and the sciences where research conducted becomes obsolete very quickly as new discoveries are made. However, when writing a review in the social sciences, a survey of the history of the literature may be required. In other words, a complete understanding the research problem requires you to deliberately examine how knowledge and perspectives have changed over time. Sort through other current bibliographies or literature reviews in the field to get a sense of what your discipline expects. You can also use this method to explore what is considered by scholars to be a "hot topic" and what is not.

III.  Ways to Organize Your Literature Review

Chronology of Events If your review follows the chronological method, you could write about the materials according to when they were published. This approach should only be followed if a clear path of research building on previous research can be identified and that these trends follow a clear chronological order of development. For example, a literature review that focuses on continuing research about the emergence of German economic power after the fall of the Soviet Union. By Publication Order your sources by publication chronology, then, only if the order demonstrates a more important trend. For instance, you could order a review of literature on environmental studies of brown fields if the progression revealed, for example, a change in the soil collection practices of the researchers who wrote and/or conducted the studies. Thematic [“conceptual categories”] A thematic literature review is the most common approach to summarizing prior research in the social and behavioral sciences. Thematic reviews are organized around a topic or issue, rather than the progression of time, although the progression of time may still be incorporated into a thematic review. For example, a review of the Internet’s impact on American presidential politics could focus on the development of online political satire. While the study focuses on one topic, the Internet’s impact on American presidential politics, it would still be organized chronologically reflecting technological developments in media. The difference in this example between a "chronological" and a "thematic" approach is what is emphasized the most: themes related to the role of the Internet in presidential politics. Note that more authentic thematic reviews tend to break away from chronological order. A review organized in this manner would shift between time periods within each section according to the point being made. Methodological A methodological approach focuses on the methods utilized by the researcher. For the Internet in American presidential politics project, one methodological approach would be to look at cultural differences between the portrayal of American presidents on American, British, and French websites. Or the review might focus on the fundraising impact of the Internet on a particular political party. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed.

Other Sections of Your Literature Review Once you've decided on the organizational method for your literature review, the sections you need to include in the paper should be easy to figure out because they arise from your organizational strategy. In other words, a chronological review would have subsections for each vital time period; a thematic review would have subtopics based upon factors that relate to the theme or issue. However, sometimes you may need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. However, only include what is necessary for the reader to locate your study within the larger scholarship about the research problem.

Here are examples of other sections, usually in the form of a single paragraph, you may need to include depending on the type of review you write:

• Current Situation : Information necessary to understand the current topic or focus of the literature review.
• Sources Used : Describes the methods and resources [e.g., databases] you used to identify the literature you reviewed.
• History : The chronological progression of the field, the research literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.
• Selection Methods : Criteria you used to select (and perhaps exclude) sources in your literature review. For instance, you might explain that your review includes only peer-reviewed [i.e., scholarly] sources.
• Standards : Description of the way in which you present your information.
• Questions for Further Research : What questions about the field has the review sparked? How will you further your research as a result of the review?

IV.  Writing Your Literature Review

Once you've settled on how to organize your literature review, you're ready to write each section. When writing your review, keep in mind these issues.

Use Evidence A literature review section is, in this sense, just like any other academic research paper. Your interpretation of the available sources must be backed up with evidence [citations] that demonstrates that what you are saying is valid. Be Selective Select only the most important points in each source to highlight in the review. The type of information you choose to mention should relate directly to the research problem, whether it is thematic, methodological, or chronological. Related items that provide additional information, but that are not key to understanding the research problem, can be included in a list of further readings . Use Quotes Sparingly Some short quotes are appropriate if you want to emphasize a point, or if what an author stated cannot be easily paraphrased. Sometimes you may need to quote certain terminology that was coined by the author, is not common knowledge, or taken directly from the study. Do not use extensive quotes as a substitute for using your own words in reviewing the literature. Summarize and Synthesize Remember to summarize and synthesize your sources within each thematic paragraph as well as throughout the review. Recapitulate important features of a research study, but then synthesize it by rephrasing the study's significance and relating it to your own work and the work of others. Keep Your Own Voice While the literature review presents others' ideas, your voice [the writer's] should remain front and center. For example, weave references to other sources into what you are writing but maintain your own voice by starting and ending the paragraph with your own ideas and wording. Use Caution When Paraphrasing When paraphrasing a source that is not your own, be sure to represent the author's information or opinions accurately and in your own words. Even when paraphrasing an author’s work, you still must provide a citation to that work.

V.  Common Mistakes to Avoid

These are the most common mistakes made in reviewing social science research literature.

• Sources in your literature review do not clearly relate to the research problem;
• You do not take sufficient time to define and identify the most relevant sources to use in the literature review related to the research problem;
• Relies exclusively on secondary analytical sources rather than including relevant primary research studies or data;
• Uncritically accepts another researcher's findings and interpretations as valid, rather than examining critically all aspects of the research design and analysis;
• Does not describe the search procedures that were used in identifying the literature to review;
• Reports isolated statistical results rather than synthesizing them in chi-squared or meta-analytic methods; and,
• Only includes research that validates assumptions and does not consider contrary findings and alternative interpretations found in the literature.

Cook, Kathleen E. and Elise Murowchick. “Do Literature Review Skills Transfer from One Course to Another?” Psychology Learning and Teaching 13 (March 2014): 3-11; Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . London: SAGE, 2011; Literature Review Handout. Online Writing Center. Liberty University; Literature Reviews. The Writing Center. University of North Carolina; Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: SAGE, 2016; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012; Randolph, Justus J. “A Guide to Writing the Dissertation Literature Review." Practical Assessment, Research, and Evaluation. vol. 14, June 2009; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016; Taylor, Dena. The Literature Review: A Few Tips On Conducting It. University College Writing Centre. University of Toronto; Writing a Literature Review. Academic Skills Centre. University of Canberra.

Writing Tip

Break Out of Your Disciplinary Box!

Thinking interdisciplinarily about a research problem can be a rewarding exercise in applying new ideas, theories, or concepts to an old problem. For example, what might cultural anthropologists say about the continuing conflict in the Middle East? In what ways might geographers view the need for better distribution of social service agencies in large cities than how social workers might study the issue? You don’t want to substitute a thorough review of core research literature in your discipline for studies conducted in other fields of study. However, particularly in the social sciences, thinking about research problems from multiple vectors is a key strategy for finding new solutions to a problem or gaining a new perspective. Consult with a librarian about identifying research databases in other disciplines; almost every field of study has at least one comprehensive database devoted to indexing its research literature.

Frodeman, Robert. The Oxford Handbook of Interdisciplinarity . New York: Oxford University Press, 2010.

Another Writing Tip

Don't Just Review for Content!

While conducting a review of the literature, maximize the time you devote to writing this part of your paper by thinking broadly about what you should be looking for and evaluating. Review not just what scholars are saying, but how are they saying it. Some questions to ask:

• How are they organizing their ideas?
• What methods have they used to study the problem?
• What theories have been used to explain, predict, or understand their research problem?
• What sources have they cited to support their conclusions?
• How have they used non-textual elements [e.g., charts, graphs, figures, etc.] to illustrate key points?

When you begin to write your literature review section, you'll be glad you dug deeper into how the research was designed and constructed because it establishes a means for developing more substantial analysis and interpretation of the research problem.

Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1 998.

Yet Another Writing Tip

When Do I Know I Can Stop Looking and Move On?

Here are several strategies you can utilize to assess whether you've thoroughly reviewed the literature:

• Look for repeating patterns in the research findings . If the same thing is being said, just by different people, then this likely demonstrates that the research problem has hit a conceptual dead end. At this point consider: Does your study extend current research?  Does it forge a new path? Or, does is merely add more of the same thing being said?
• Look at sources the authors cite to in their work . If you begin to see the same researchers cited again and again, then this is often an indication that no new ideas have been generated to address the research problem.
• Search Google Scholar to identify who has subsequently cited leading scholars already identified in your literature review [see next sub-tab]. This is called citation tracking and there are a number of sources that can help you identify who has cited whom, particularly scholars from outside of your discipline. Here again, if the same authors are being cited again and again, this may indicate no new literature has been written on the topic.

Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: Sage, 2016; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

• << Previous: Theoretical Framework
• Next: Citation Tracking >>
• Last Updated: May 15, 2024 9:53 AM
• URL: https://libguides.usc.edu/writingguide

Conduct a literature review

What is a literature review.

A literature review is a summary of the published work in a field of study. This can be a section of a larger paper or article, or can be the focus of an entire paper. Literature reviews show that you have examined the breadth of knowledge and can justify your thesis or research questions. They are also valuable tools for other researchers who need to find a summary of that field of knowledge.

Unlike an annotated bibliography, which is a list of sources with short descriptions, a literature review synthesizes sources into a summary that has a thesis or statement of purpose—stated or implied—at its core.

How do I write a literature review?

Step 1: define your research scope.

• What is the specific research question that your literature review helps to define?
• Are there a maximum or minimum number of sources that your review should include?

Ask us if you have questions about refining your topic, search methods, writing tips, or citation management.

Step 2: Identify the literature

Start by searching broadly. Literature for your review will typically be acquired through scholarly books, journal articles, and/or dissertations. Develop an understanding of what is out there, what terms are accurate and helpful, etc., and keep track of all of it with citation management tools . If you need help figuring out key terms and where to search, ask us .

Use citation searching to track how scholars interact with, and build upon, previous research:

• Mine the references cited section of each relevant source for additional key sources
• Use Google Scholar or Scopus to find other sources that have cited a particular work

Step 3: Critically analyze the literature

Key to your literature review is a critical analysis of the literature collected around your topic. The analysis will explore relationships, major themes, and any critical gaps in the research expressed in the work. Read and summarize each source with an eye toward analyzing authority, currency, coverage, methodology, and relationship to other works. The University of Toronto's Writing Center provides a comprehensive list of questions you can use to analyze your sources.

Step 4: Categorize your resources

Divide the available resources that pertain to your research into categories reflecting their roles in addressing your research question. Possible ways to categorize resources include organization by:

• methodology
• theoretical/philosophical approach

Regardless of the division, each category should be accompanied by thorough discussions and explanations of strengths and weaknesses, value to the overall survey, and comparisons with similar sources. You may have enough resources when:

• You've used multiple databases and other resources (web portals, repositories, etc.) to get a variety of perspectives on the research topic.
• The same citations are showing up in a variety of databases.

Additional resources

Undergraduate student resources.

• Literature Review Handout (University of North Carolina at Chapel Hill)
• Learn how to write a review of literature (University of Wisconsin-Madison)

Graduate student and faculty resources

• Information Research Strategies (University of Arizona)
• Literature Reviews: An Overview for Graduate Students (NC State University)
• Oliver, P. (2012). Succeeding with Your Literature Review: A Handbook for Students [ebook]
• Machi, L. A. & McEvoy, B. T. (2016). The Literature Review: Six Steps to Success

Graustein, J. S. (2012). How to Write an Exceptional Thesis or Dissertation: A Step-by-Step Guide from Proposal to Successful Defense [ebook]

Thomas, R. M. & Brubaker, D. L. (2008). Theses and Dissertations: A Guide to Planning, Research, and Writing

• University of Texas Libraries

Literature Reviews

• What is a literature review?
• Steps in the Literature Review Process
• Define your research question
• Determine inclusion and exclusion criteria
• Choose databases and search
• Review Results
• Synthesize Results
• Analyze Results
• Librarian Support

What is a Literature Review?

A literature or narrative review is a comprehensive review and analysis of the published literature on a specific topic or research question. The literature that is reviewed contains: books, articles, academic articles, conference proceedings, association papers, and dissertations. It contains the most pertinent studies and points to important past and current research and practices. It provides background and context, and shows how your research will contribute to the field. 

A literature review should: 

• Provide a comprehensive and updated review of the literature;
• Explain why this review has taken place;
• Articulate a position or hypothesis;
• Acknowledge and account for conflicting and corroborating points of view

From  S age Research Methods

Purpose of a Literature Review

A literature review can be written as an introduction to a study to:

• Demonstrate how a study fills a gap in research
• Compare a study with other research that's been done

Or it can be a separate work (a research article on its own) which:

• Organizes or describes a topic
• Describes variables within a particular issue/problem

Limitations of a Literature Review

Some of the limitations of a literature review are:

• It's a snapshot in time. Unlike other reviews, this one has beginning, a middle and an end. There may be future developments that could make your work less relevant.
• It may be too focused. Some niche studies may miss the bigger picture.
• It can be difficult to be comprehensive. There is no way to make sure all the literature on a topic was considered.
• It is easy to be biased if you stick to top tier journals. There may be other places where people are publishing exemplary research. Look to open access publications and conferences to reflect a more inclusive collection. Also, make sure to include opposing views (and not just supporting evidence).

Source: Grant, Maria J., and Andrew Booth. “A Typology of Reviews: An Analysis of 14 Review Types and Associated Methodologies.” Health Information & Libraries Journal, vol. 26, no. 2, June 2009, pp. 91–108. Wiley Online Library, doi:10.1111/j.1471-1842.2009.00848.x.

Meryl Brodsky : Communication and Information Studies

Hannah Chapman Tripp : Biology, Neuroscience

Carolyn Cunningham : Human Development & Family Sciences, Psychology, Sociology

Larayne Dallas : Engineering

Janelle Hedstrom : Special Education, Curriculum & Instruction, Ed Leadership & Policy ​

Susan Macicak : Linguistics

Imelda Vetter : Dell Medical School

For help in other subject areas, please see the guide to library specialists by subject .

Periodically, UT Libraries runs a workshop covering the basics and library support for literature reviews. While we try to offer these once per academic year, we find providing the recording to be helpful to community members who have missed the session. Following is the most recent recording of the workshop, Conducting a Literature Review. To view the recording, a UT login is required.

• October 26, 2022 recording
• Last Updated: Oct 26, 2022 2:49 PM
• URL: https://guides.lib.utexas.edu/literaturereviews

How to write a Literature Review: Home

• Literature review process
• Purpose of a literature review
• Evaluating sources
• Managing sources
• Request a literature search
• Selecting the approach to use
• Quantitative vs qualitative method
• Summary of different research methodologies
• Research design vs research methodology
• Diagram: importance of research
• Attributes of a good research scholar

Useful information

Visit our  Ask a Librarian  page if you want to contact us or if you have a question.

Postgraduate services

Requesting and downloading library material

Guidelines for submission of electronic versions of theses and dissertations 

Click here for more information on the UnisaIR.

What is a literature review

A literature review is a  critical evaluation  of what has been published on a topic by accredited scholars and researchers.  In other words literature reviews are secondary sources, and as such, do not report any new or original experimental work.  Thus, a literature review is not descriptive but analytical in nature. 

More information ...

It is important, however, that you select your sources carefully as you do not have to include everything that you have read on a topic. You must concentrate on publications that have influenced the field you are writing about. Ensure that you use publications that are written by reputable authors.

"A literature review is a piece of  discursive prose , not a list describing or summarizing one piece of literature after another. It's usually a bad sign to see every paragraph beginning with the name of a researcher. Instead, organize the literature review into sections that present themes or identify trends, including relevant theory. You are not trying to list all the material published, but to synthesize and evaluate it according to the guiding concept of your thesis or research question" (Taylor, D. n.d.).

  Source : Taylor D. (n.d.)  T he Literature review: a few tips on conducting it.

Literature review - questions to ask yourself

Useful links.

• Find e-resources
• Find e-journals and e-books
• Search Summon
• Unisa Institutional Repository
• Library Catalogue
• Next: Literature review process >>
• Last Updated: Apr 30, 2024 1:19 PM
• URL: https://libguides.unisa.ac.za/literature_review

Literature Reviews

• 1. Define your research question
• Getting started
• Types of reviews

Define topic

Brainstorming, limit scope, how ai can help, helpful resources.

• 2. Plan your search
• 3. Search the literature
• 4. Organize your results
• 5. Synthesize your findings
• 6. Write the review
• Artificial intelligence (AI) tools
• Thompson Writing Studio This link opens in a new window
• Need to write a systematic review? This link opens in a new window

Contact a Librarian

Ask a Librarian

Mission animated icons created by Freepik - Flaticon

For example, the following research question is too broad.

Does social media affect mental health in college students?

A more focused research question could be:

Does social media play a role in the number of eating disorder diagnoses in college-aged women?

Need some guidance? Contact your subject librarian for a research consultation or reach out to [email protected] .

Start the brainstorming process:

• Begin by identifying a broad topic of research interest (the more you're personally interested in it, the better!). Write it down to clarify your focus.
• Narrow down your scope  by considering specific areas within this topic that you want to explore.
• Identify key themes and elements  related to these specific areas. These will be the building blocks of your investigation.
• Finally,  integrate these key areas and elements  into a well-crafted research question.

One way to brainstorm is to use a flowchart.

The scope of a topic  encompasses the boundaries and constraints you set for your research. The more precise your research question, the smoother the research process becomes.

Feeling stuck? Here are some ways you can narrow down your topic:

• geographic location
• time period
• discipline/field of study
• age group, etc.

You:  I need to conduct a literature review about social media, mental health, and college students. What are some example research questions within this topic?

ChatGPT: 

• How does the frequency and nature of social media use impact the mental health of college students?
• What role do specific social media platforms play in influencing the mental well-being of college students?
• How do online social interactions on platforms like Facebook, Instagram, or Twitter relate to the mental health outcomes of college students?
• Are there differences in the association between social media use and mental health outcomes based on demographic factors such as gender, age, or academic major among college students?
• What strategies do college students employ to cope with negative mental health effects associated with social media use?
• How does the perception of social support through online platforms affect the mental health of college students?
• To what extent does the comparison of oneself to others on social media contribute to mental health challenges among college students?
• What interventions or educational programs are effective in promoting positive mental health behaviors in the context of social media use for college students?
• How do social media literacy and awareness programs impact the mental health attitudes and behaviors of college students?
• What is the relationship between the use of social media for academic and social purposes and the mental health outcomes of college students?

Generative AI tools : ChatGPT , Google Gemini (formerly Bard) , Claude , Microsoft Copilot

For more information on how to incorporate AI tools into your research, check out the section on AI Tools .

• Developing Your Research Question
• Developing a Researchable Question
• Brainstorming tips from UNC Writing Center
• << Previous: Types of reviews
• Next: 2. Plan your search >>
• Last Updated: May 17, 2024 8:42 AM
• URL: https://guides.library.duke.edu/litreviews

Services for...

• Faculty & Instructors
• Graduate Students
• Undergraduate Students
• International Students
• Patrons with Disabilities

• Harmful Language Statement
• Re-use & Attribution / Privacy
• Support the Libraries

• Search This Site All UCSD Sites Faculty/Staff Search Term
• Contact & Directions
• Climate Statement
• Cognitive Behavioral Neuroscience
• Cognitive Psychology
• Developmental Psychology
• Social Psychology
• Adjunct Faculty
• Non-Senate Instructors
• Researchers
• Psychology Grads
• Affiliated Grads
• New and Prospective Students
• Honors Program
• Experiential Learning
• Programs & Events
• Psi Chi / Psychology Club
• Prospective PhD Students
• Current PhD Students
• Area Brown Bags
• Colloquium Series
• Anderson Distinguished Lecture Series
• Speaker Videos
• Undergraduate Program
• Academic and Writing Resources

Writing Research Papers

• Writing a Literature Review

When writing a research paper on a specific topic, you will often need to include an overview of any prior research that has been conducted on that topic.  For example, if your research paper is describing an experiment on fear conditioning, then you will probably need to provide an overview of prior research on fear conditioning.  That overview is typically known as a literature review.  

Please note that a full-length literature review article may be suitable for fulfilling the requirements for the Psychology B.S. Degree Research Paper .  For further details, please check with your faculty advisor.

Different Types of Literature Reviews

Literature reviews come in many forms.  They can be part of a research paper, for example as part of the Introduction section.  They can be one chapter of a doctoral dissertation.  Literature reviews can also “stand alone” as separate articles by themselves.  For instance, some journals such as Annual Review of Psychology , Psychological Bulletin , and others typically publish full-length review articles.  Similarly, in courses at UCSD, you may be asked to write a research paper that is itself a literature review (such as, with an instructor’s permission, in fulfillment of the B.S. Degree Research Paper requirement). Alternatively, you may be expected to include a literature review as part of a larger research paper (such as part of an Honors Thesis). 

Literature reviews can be written using a variety of different styles.  These may differ in the way prior research is reviewed as well as the way in which the literature review is organized.  Examples of stylistic variations in literature reviews include: 

• Summarization of prior work vs. critical evaluation. In some cases, prior research is simply described and summarized; in other cases, the writer compares, contrasts, and may even critique prior research (for example, discusses their strengths and weaknesses).
• Chronological vs. categorical and other types of organization. In some cases, the literature review begins with the oldest research and advances until it concludes with the latest research.  In other cases, research is discussed by category (such as in groupings of closely related studies) without regard for chronological order.  In yet other cases, research is discussed in terms of opposing views (such as when different research studies or researchers disagree with one another).

Overall, all literature reviews, whether they are written as a part of a larger work or as separate articles unto themselves, have a common feature: they do not present new research; rather, they provide an overview of prior research on a specific topic . 

How to Write a Literature Review

When writing a literature review, it can be helpful to rely on the following steps.  Please note that these procedures are not necessarily only for writing a literature review that becomes part of a larger article; they can also be used for writing a full-length article that is itself a literature review (although such reviews are typically more detailed and exhaustive; for more information please refer to the Further Resources section of this page).

Steps for Writing a Literature Review

1. Identify and define the topic that you will be reviewing.

The topic, which is commonly a research question (or problem) of some kind, needs to be identified and defined as clearly as possible.  You need to have an idea of what you will be reviewing in order to effectively search for references and to write a coherent summary of the research on it.  At this stage it can be helpful to write down a description of the research question, area, or topic that you will be reviewing, as well as to identify any keywords that you will be using to search for relevant research.

2. Conduct a literature search.

Use a range of keywords to search databases such as PsycINFO and any others that may contain relevant articles.  You should focus on peer-reviewed, scholarly articles.  Published books may also be helpful, but keep in mind that peer-reviewed articles are widely considered to be the “gold standard” of scientific research.  Read through titles and abstracts, select and obtain articles (that is, download, copy, or print them out), and save your searches as needed.  For more information about this step, please see the Using Databases and Finding Scholarly References section of this website.

3. Read through the research that you have found and take notes.

Absorb as much information as you can.  Read through the articles and books that you have found, and as you do, take notes.  The notes should include anything that will be helpful in advancing your own thinking about the topic and in helping you write the literature review (such as key points, ideas, or even page numbers that index key information).  Some references may turn out to be more helpful than others; you may notice patterns or striking contrasts between different sources ; and some sources may refer to yet other sources of potential interest.  This is often the most time-consuming part of the review process.  However, it is also where you get to learn about the topic in great detail.  For more details about taking notes, please see the “Reading Sources and Taking Notes” section of the Finding Scholarly References page of this website.

4. Organize your notes and thoughts; create an outline.

At this stage, you are close to writing the review itself.  However, it is often helpful to first reflect on all the reading that you have done.  What patterns stand out?  Do the different sources converge on a consensus?  Or not?  What unresolved questions still remain?  You should look over your notes (it may also be helpful to reorganize them), and as you do, to think about how you will present this research in your literature review.  Are you going to summarize or critically evaluate?  Are you going to use a chronological or other type of organizational structure?  It can also be helpful to create an outline of how your literature review will be structured.

5. Write the literature review itself and edit and revise as needed.

The final stage involves writing.  When writing, keep in mind that literature reviews are generally characterized by a summary style in which prior research is described sufficiently to explain critical findings but does not include a high level of detail (if readers want to learn about all the specific details of a study, then they can look up the references that you cite and read the original articles themselves).  However, the degree of emphasis that is given to individual studies may vary (more or less detail may be warranted depending on how critical or unique a given study was).   After you have written a first draft, you should read it carefully and then edit and revise as needed.  You may need to repeat this process more than once.  It may be helpful to have another person read through your draft(s) and provide feedback.

6. Incorporate the literature review into your research paper draft.

After the literature review is complete, you should incorporate it into your research paper (if you are writing the review as one component of a larger paper).  Depending on the stage at which your paper is at, this may involve merging your literature review into a partially complete Introduction section, writing the rest of the paper around the literature review, or other processes.

Further Tips for Writing a Literature Review

Full-length literature reviews

• Many full-length literature review articles use a three-part structure: Introduction (where the topic is identified and any trends or major problems in the literature are introduced), Body (where the studies that comprise the literature on that topic are discussed), and Discussion or Conclusion (where major patterns and points are discussed and the general state of what is known about the topic is summarized)

Literature reviews as part of a larger paper

• An “express method” of writing a literature review for a research paper is as follows: first, write a one paragraph description of each article that you read. Second, choose how you will order all the paragraphs and combine them in one document.  Third, add transitions between the paragraphs, as well as an introductory and concluding paragraph. 1
• A literature review that is part of a larger research paper typically does not have to be exhaustive. Rather, it should contain most or all of the significant studies about a research topic but not tangential or loosely related ones. 2   Generally, literature reviews should be sufficient for the reader to understand the major issues and key findings about a research topic.  You may however need to confer with your instructor or editor to determine how comprehensive you need to be.

Benefits of Literature Reviews

By summarizing prior research on a topic, literature reviews have multiple benefits.  These include:

• Literature reviews help readers understand what is known about a topic without having to find and read through multiple sources.
• Literature reviews help “set the stage” for later reading about new research on a given topic (such as if they are placed in the Introduction of a larger research paper). In other words, they provide helpful background and context.
• Literature reviews can also help the writer learn about a given topic while in the process of preparing the review itself. In the act of research and writing the literature review, the writer gains expertise on the topic .

Downloadable Resources

• How to Write APA Style Research Papers (a comprehensive guide) [ PDF ]
• Tips for Writing APA Style Research Papers (a brief summary) [ PDF ]
• Example APA Style Research Paper (for B.S. Degree – literature review) [ PDF ]

Further Resources

How-To Videos     

• Writing Research Paper Videos
• UCSD Library Psychology Research Guide: Literature Reviews

External Resources

• Developing and Writing a Literature Review from N Carolina A&T State University
• Example of a Short Literature Review from York College CUNY
• How to Write a Review of Literature from UW-Madison
• Writing a Literature Review from UC Santa Cruz  
• Pautasso, M. (2013). Ten Simple Rules for Writing a Literature Review. PLoS Computational Biology, 9 (7), e1003149. doi : 1371/journal.pcbi.1003149

1 Ashton, W. Writing a short literature review . [PDF]     

2 carver, l. (2014).  writing the research paper [workshop]. , prepared by s. c. pan for ucsd psychology.

Back to top

• Research Paper Structure
• Formatting Research Papers
• Using Databases and Finding References
• What Types of References Are Appropriate?
• Evaluating References and Taking Notes
• Citing References
• Writing Process and Revising
• Improving Scientific Writing
• Academic Integrity and Avoiding Plagiarism
• Writing Research Papers Videos

Myositis as a prominent manifestation of primary skeletal muscle peripheral T-cell lymphoma: a case report and literature review

• CASE BASED REVIEW
• Published: 15 May 2024

Cite this article

• Zhengyi Jin   ORCID: orcid.org/0009-0005-6477-3066 1 ,
• Jiaqi Hu 1 ,
• Thumon Min 1 ,
• Lixia Chen 1 ,
• Fang Zhang 2 ,
• Ruina Kong 1 &
• Jie Gao   ORCID: orcid.org/0000-0003-1075-3631 1  

The patient presented to the clinic with painful muscle swelling in the right lower extremity, which improved with immunosuppressive therapy. Initially, the condition was diagnosed as polymyositis but recurred soon after. After imaging and biopsy, the final diagnosis was primary skeletal muscle peripheral T-cell lymphoma, not otherwise specified (PSM-PTCL, NOS). In this report, we discuss the challenges in diagnosing and treating this aggressive malignancy and review the literature on PSM-PTCL, NOS.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price includes VAT (Russian Federation)

Instant access to the full article PDF.

Rent this article via DeepDyve

Institutional subscriptions

Data availability

The data are available from the corresponding author on reasonable request.

Murphey MD, Kransdorf MJ (2016) Primary musculoskeletal lymphoma. Radiol Clin N Am 54:785–795. https://doi.org/10.1016/j.rcl.2016.03.008

Article   PubMed   Google Scholar  

Bowzyk AA, Ajithkumar T, Behan S, Hodson DJ (2018) Non-Hodgkin lymphoma. BMJ-Br Med J 362:k3204. https://doi.org/10.1136/bmj.k3204

Article   Google Scholar  

Iizuka H, Harada S, Iwao N, Koike M, Noguchi M (2021) Primary skeletal muscle peripheral T-cell lymphoma: an autopsy case report and review of the literature. Intern Med 60:3309–3315. https://doi.org/10.2169/internalmedicine.7391-21

Article   PubMed   PubMed Central   Google Scholar  

Hou WH, Zhou XG, Xie JL, Zheng YY, Zhang YL, Wang X (2021) Clinicopathological features and prognosis of the skeletal-muscle cytotoxic T-cell lymphoma. Zhonghua Bing Li Xue Za Zhi. 50:1246–1251. https://doi.org/10.3760/cma.j.cn112151-20210602-00403

Article   CAS   PubMed   Google Scholar  

Binici D, Karaman A, Timur O, Tasar P, Sanibas AV (2018) Primary skeletal muscle lymphoma: a case report. Mol Clin Oncol 8:80–82. https://doi.org/10.3892/mco.2017.1483

Ashton C, Paramalingam S, Stevenson B, Brusch A, Needham M (2021) Idiopathic inflammatory myopathies: a review. Intern Med J 51:845–852. https://doi.org/10.1111/imj.15358

Dourado E, Bottazzi F, Cardelli C, Conticini E, Schmidt J, Cavagna L, Barsotti S (2023) Idiopathic inflammatory myopathies: one year in review 2022. Clin Exp Rheumatol 41:199–213. https://doi.org/10.55563/clinexprheumatol/jof6qn

Bohan A, Peter JB (1975) Polymyositis and dermatomyositis (first of two parts). N Engl J Med 292:344–347. https://doi.org/10.1056/NEJM197502132920706

Bohan A, Peter JB (1975) Polymyositis and dermatomyositis (second of two parts). N Engl J Med 292:403–407. https://doi.org/10.1056/NEJM197502202920807

Lundberg IE, Tjarnlund A, Bottai M, Werth VP, Pilkington C, Visser M, Alfredsson L, Amato AA, Barohn RJ, Liang MH et al (2017) 2017 European league against rheumatism/American College of Rheumatology classification criteria for adult and juvenile idiopathic inflammatory myopathies and their major subgroups. Ann Rheum Dis 76:1955–1964. https://doi.org/10.1136/annrheumdis-2017-211468

Rieux-Laucat F, Kanellopoulos JM, Ojcius DM (2021) Scaling the tips of the ALPS. Biomed J 44:383–387. https://doi.org/10.1016/j.bj.2021.08.002

Article   CAS   PubMed   PubMed Central   Google Scholar  

Palmisani E, Miano M, Grossi A, Lanciotti M, Lupia M, Terranova P, Ceccherini I, Montanari E, Calvillo M, Pierri F et al (2023) Autoimmune lymphoproliferative syndrome (ALPS) disease and ALPS phenotype: are they two distinct entities? Hemasphere 7:e845. https://doi.org/10.1097/HS9.0000000000000845

Oliveira JB, Bleesing JJ, Dianzani U, Fleisher TA, Jaffe ES, Lenardo MJ, Rieux-Laucat F, Siegel RM, Su HC, Teachey DT et al (2010) Revised diagnostic criteria and classification for the autoimmune lymphoproliferative syndrome (ALPS): report from the 2009 NIH International Workshop. Blood. 116:e35–e40. https://doi.org/10.1182/blood-2010-04-280347

Loudini N, Glaudemans A, Jutte PC, Suurmeijer A, Yakar D, Kwee TC (2019) The diagnostic significance of repeat ultrasound-guided biopsy of musculoskeletal soft-tissue lesions with initially inconclusive biopsy results. EJSO 45:1266–1273. https://doi.org/10.1016/j.ejso.2019.01.185

Surov A (2014) Imaging findings of skeletal muscle lymphoma. Clin Imaging 38:594–598. https://doi.org/10.1016/j.clinimag.2014.03.006

Gao S, Shu H, Yang H (2021) Imaging features of skeletal muscle lymphoma: a case report and literature review. BMC Med Imag 21:136. https://doi.org/10.1186/s12880-021-00667-4

Download references

Author information

Authors and affiliations.

Department of Rheumatology and Immunology, The First Affiliated Hospital of Naval Medical University, Shanghai, 200433, China

Zhengyi Jin, Jiaqi Hu, Thumon Min, Lixia Chen, Ruina Kong & Jie Gao

Department of Nuclear Medicine, The First Affiliated Hospital of Naval Medical University, Shanghai, 200433, China

You can also search for this author in PubMed   Google Scholar

Contributions

Zhengyi Jin, Jiaqi Hu, and Thumon Min contributed equally to this work and should be considered co-first authors.

Corresponding authors

Correspondence to Ruina Kong or Jie Gao .

Ethics declarations

Ethics approval.

This study followed the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments; written informed consent was obtained; it was explained to the patient; she understood it, and she subsequently signed and was approved by the ethics committee of the institution. Details about the identity of the patient under study were omitted.

Disclosures

Additional information, publisher's note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Jin, Z., Hu, J., Min, T. et al. Myositis as a prominent manifestation of primary skeletal muscle peripheral T-cell lymphoma: a case report and literature review. Clin Rheumatol (2024). https://doi.org/10.1007/s10067-024-07003-5

Download citation

Received : 29 February 2024

Revised : 25 April 2024

Accepted : 09 May 2024

Published : 15 May 2024

DOI : https://doi.org/10.1007/s10067-024-07003-5

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Skeletal muscle
• T-cell lymphoma
• Find a journal
• Publish with us
• Track your research

• Case report
• Open access
• Published: 14 May 2024

Portal vein thrombosis as extraintestinal complications of Crohn’s disease: a case report and review of literature

• Marouf Alhalabi   ORCID: orcid.org/0000-0001-5027-2096 1 ,
• Duaa Nasri 1 &
• Widad Aji 1  

Journal of Medical Case Reports volume  18 , Article number:  246 ( 2024 ) Cite this article

58 Accesses

1 Altmetric

Metrics details

Introduction

Thrombotic events are more than twice as common in inflammatory bowel disease patients as in the general population. We report an interesting and rare case of portal vein thrombosis as a venous thromboembolic event in the context of extraintestinal manifestations of Crohn’s disease. We also conducted a literature review on portal vein thrombosis associated with inflammatory bowel disease, with the following concepts: inflammatory bowel diseases, ulcerative colitis, Crohn’s disease, portal vein, and thrombosis.

Case presentation

A 24-year-old Syrian female with active chronic Crohn’s disease was diagnosed 11 years ago and classified as A1L3B1P according to the Montreal classification. She had no prior surgical history. Her previous medications included azathioprine and prednisolone. Her Crohn’s disease activity index was 390 points. Gastroduodenoscopy revealed grade I esophageal varices, a complication of portal hypertension. Meanwhile, a colonoscopy revealed several deep ulcers in the sigmoid, rectum, and descending colon. An investigation of portal vein hypertension revealed portal vein thrombosis. We used corticosteroids to induce remission, followed by tapering; additionally she received ustekinumab to induce and maintain remission. She began on low-molecular-weight heparin for 1 week, warfarin for 3 months, and then apixaban, a novel oral anticoagulant, after excluding antiphospholipid syndrome. Primary prophylaxis for esophageal varices was not required. After 1 year, she achieved clinical, biochemical, and endoscopic remission. Despite 1 year of treatment, a computed tomography scan revealed no improvement in portal vein recanalization.

Portal vein thrombosis is a rare and poorly defined complication of inflammatory bowel disease. It is usually exacerbated by inflammatory bowel disease. The symptoms are nonspecific and may mimic a flare-up of inflammatory bowel disease, making the diagnosis difficult. Portal vein Doppler ultrasound for hospital-admitted inflammatory bowel disease patients may contribute to the diagnosis and management of this complication.

Peer Review reports

Extraintestinal manifestations can affect almost any organ system and have a negative impact on the patient’s functional status and quality of life. Extraintestinal manifestations are most commonly observed in the joints, skin, hepatobiliary tract, eyes, heart, pancreas, and vascular system. Portal vein thrombosis (PVT) is an obscure and poorly defined complication of many diseases, including cirrhosis, intraabdominal infection, intraabdominal surgery, pancreatitis, primary hematologic disorders, and inflammatory bowel disease (IBD) [ 1 ]. The prevalence of PVT in patients with IBD ranges from 0.17% to 1.7% [ 1 ], and may be associated with inherited or acquired hypercoagulability risk factors and has a benign outcome [ 1 ]. It can be difficult to diagnose PVT in patients with IBD because its extremely generic symptoms, such as abdominal discomfort, can frequently originate from any of its triggering events. Therefore, it should come as no surprise that the diagnosis is frequently made by accident when imaging is performed to check for one of these triggering processes, also the laboratory results are nonspecific [ 1 ]. We report an interesting and uncommon case of PVT associated with Crohn’s disease that was discovered when investigating the cause of esophageal varices related to portal vein hypertension. We also conducted a literature review on portal vein thrombosis associated with inflammatory bowel disease using the following concepts: inflammatory bowel disease, ulcerative colitis, Crohn’s disease, portal vein, and thrombosis.

We evaluated a 24-year-old Syrian female with active chronic Crohn’s disease, diagnosed 11 years ago. She was classified as A1L3B1P according to the Montreal classification [ 2 ]. She had no prior surgical history; her past medications included azathioprine 2.5 mg/kg/day since diagnosis until now and prednisolone 1 mg/kg up to 40 mg during flares, then tapering [ 3 ]. Furthermore, she did not use oral contraceptive pills. Her weight was 50 kg, her height was 161 cm, and she had a body mass index of 19.29 kg/m 2 . She complained of watery, bloody diarrhea up to eight times a day, accompanied by abdominal pain in the prior month. Her Crohn’s disease activity index (CDAI) was 390 points. Initial blood tests confirmed leukocytosis, anemia, elevated fecal calprotectin (FC), and C-reactive protein (CRP) levels. Stool cultures, Clostridium difficile toxin, Escherichia coli , and Cryptosporidium , as well as microscopy for ova and parasites, all returned negative. The hypercoagulability work-up revealed negative results for anti-Beta-2 Glycoprotein-1 IgM antibodies, antinuclear antibodies (ANA), fibrinogen, protein S (activity), antithrombin III, and homocysteine, whereas lupus anticoagulant (LA1, LA2) was positive. Factor II mutation and factor V Leiden mutation were normal, whereas the methylenetetrahydrofolate reductase mutation was a homozygous mutant gene. The portal system and suprahepatic vein ultrasound revealed a thrombus that covered nearly half of the lumen of the portal vein and splenomegaly. Gogastroduodenoscopy showed grade I esophageal varices (less than 5 mm, without bleeding risk signs), which indicate portal vein hypertension owing to splenomegaly and esophageal varices. In light of the patient’s recent onset of abdominal pain and the absence of portosystemic collaterals on Doppler ultrasound, a recent PVT is a strong possibility [ 4 ]. The colonoscopy revealed several deep ulcers in the sigmoid, rectum, and descending colon Fig.  1 . The biopsies were negative for Clostridium difficile , and immunohistochemical staining was negative for cytomegalovirus (CMV) [ 3 , 5 ]. The median liver stiffness measured by FibroScan was 2.4 kPa, which suggests the absence of fibrosis. Protein electrophoresis was normal. The abdomen and pelvis contrast-enhanced computed tomography (CT) scan confirmed the PVT and displayed thickening in the descending colon (Fig.  2 ). Antiphospholipid syndrome was initially diagnosed on the basis of an antiphospholipid profile, a history of PVT (thrombotic event), and an association with Crohn’s disease [ 6 ]. She initially received corticosteroids to achieve disease remission, followed by ustekinumab to induce and maintain therapy (390 mg intravenous induction followed by 90 mg subcutaneous every 8 weeks) owing to moderate-to-severe Crohn’s disease unresponsive to azathioprine [ 7 , 8 ]. She began on low-molecular-weight heparin (LMWH) for 1 week, and warfarin for 3 months with an international normalized ratio (INR) target of 2–3. The lupus anticoagulant (LA1, LA2) was retested after 12 weeks and returned to negative [ 6 ], so we switched to apixaban, a novel oral anticoagulant (NOAC) [ 4 ]. The 1-year reevaluation indicated clinical, biochemical, and endoscopic remission with CDAI of 150 points, normal lab test, and normal endoscopy. The patient’s tests are presented in Table  1 . Despite 1 year of treatment, a CT scan revealed no improvement in portal vein recanalization. We continued 90 mg of subcutaneous (SC) ustekinumab every 8 weeks, while we stopped apixaban [ 3 , 4 ].

Colonoscopy revealed several ulcerations in the sigmoid, rectum, and descending colon

The contrast-enhanced computed tomography scan of the abdomen, which shows portal vein thrombosis

Review of literature

To facilitate this literature review, we used a combination of keywords and database subject headings to search the MEDLINE (through PubMed) database on 1 July 2023 for the following concepts: Crohn’s disease, ulcerative colitis, IBD, portal vein, PVT, and thrombosis. We also manually searched the reference lists of the included papers. We returned the research on 7 April 2024, and no new findings were obtained.

Eligibility criteria

We searched for any case reports, case series, observational, or interventional studies that addressed portal vein thrombosis associated with inflammatory bowel disease. Table 2 summarizes the basic features and treatment outcomes of the reported cases.

Crohn’s disease is linked to a variety of extraintestinal complications. Oral aphthous ulcers, peripheral arthritis, erythema nodosum, and episcleritis are frequently associated with active intestinal disease. Whereas uveitis and ankylosing spondylitis are usually unrelated to disease activity, pyoderma gangrenosum and primary sclerosing cholangitis have a questionable relationship to disease activity [ 9 ]. Venous thromboembolic events are fearsome manifestations that are related to disease activity and associated with significant morbidity and mortality [ 9 ]. Deep vein thrombosis (DVT) is the most prevalent thrombotic event, followed by pulmonary embolism (PE). The relative risk of thrombotic events in patients with inflammatory bowel disease was 2.03 [ 10 ]. Although inflammatory bowel disease treatment options have improved over the last three decades [ 11 ], thrombotic events among hospitalized individuals with inflammatory bowel disease continued to rise [ 12 ]. The overall thrombotic risk did not differ between sexes or between individuals who have ulcerative colitis or Crohn’s disease [ 13 ]. There have been very few reports of portal vein thrombosis in the context of inflammatory bowel disease. The presenting indications, symptoms, and laboratory data are all extremely nonspecific, and a PVT diagnosis is nearly always made by chance. It is important to note that PVT is related to disease activity, particularly IBD flare. We found that portal vein thrombosis affects both men and women, with a small male predominance. It is also more frequent in individuals with ulcerative colitis than in those with Crohn’s disease. It is a rare complication in Crohn’s disease, identified in only 14 cases. Hypercoagulability testing in a subset of patients (around half) revealed inherited or acquired hypercoagulability factors in some, with antiphospholipid antibodies and factor V Leiden mutation being the most common. Treatment for thrombosis in Crohn’s disease involves tailored anticoagulation (heparin, warfarin, DOACs) or even surgery, with outcomes ranging from successful resolution to bleeding or death. However, limitations include the use of case reports and retrospective studies, and the small number of CD cases, which hinder definitive conclusions. There are no recommendations for thrombophilia screening in cases of portal vein thrombosis; many reports, including ours, have included thrombophilia testing. Naymagon et al . suggested that thrombophilia testing is not required in cases of clearly triggered PVT, such as after recent surgery or in the setting of a recent or active intraabdominal infection or IBD-flare [ 1 ]; moreover, he suggested that thrombophilia testing should be undertaken if PVT is not induced, such as spontaneous PVT in an otherwise stable and inactive IBD patient, or patients with a history of previous venous thromboembolism or unexplained blood count abnormalities [ 1 ]. Furthermore, testing for antiphospholipid syndrome and paroxysmal nocturnal hemoglobinuria may affect management and should be considered in certain conditions, such as a history of autoimmune disease or arterial thrombosis for antiphospholipid syndrome and unexplained cytopenia or evidence of intravascular hemolysis for paroxysmal nocturnal hemoglobinuria. Other thrombophilia testing are often unnecessary because the results have little impact on therapy [ 1 ]. A mutation of JAK2 could be detected in splanchnic vein thrombosis and thus provide a marker of latent myeloproliferative neoplasms (MPNs), which are a major primary cause of abdominal vein thrombosis [ 14 ]. MPNs are made up of three key rare diseases: (1) polycythemia vera, which leads to an elevation in all blood cells, especially red blood cells; (2) essential thrombocythemia, which leads to an increase in platelets; and (3) primary myelofibrosis, a bone marrow disorder that leads to defects in blood cell production [ 14 , 15 ]. MPNs were diagnosed through a variety of criteria, including the typical alterations in peripheral blood cells [ 4 ], as she had chronic active CD with possible previous CD-flare and a normal blood profile which excludes MPNs [ 1 , 14 , 15 ]. We screened for antiphospholipid syndrome antibodies because the patient was a young female with a significant thrombotic event without a clear relationship with a Crohn’s disease flare. Although the lupus anticoagulant (LA1, LA2) was initially positive, it was found to be negative 12 weeks later. The explanations for the false positive in our instance were anticoagulant treatment, including therapy with LWMH, which is indicated to every patient admitted to the hospital with inflammatory bowel disease, and later warfarin for the management of portal vein thrombosis [ 3 , 6 , 13 ]. For PVT management, literature was unclear concerning the selection of anticoagulants. Most patients who require anticoagulation are started on LMWH, or unfractionated heparin, and then switched to vitamin K antagonists (VKAs) to maintain a goal international normalization rate of 2–3. While VKAs can be substituted orally with direct oral anticoagulants (DOACs) or novel oral anticoagulants (NOACs). These medications do not require monitoring of the INR because of their speedier onset of action and lesser risk of bleeding. DOACs are just as effective as VKAs for treating deep vein thrombosis, pulmonary embolism, and stroke prevention in patients with atrial fibrillation, and may be considered owing to potentially less frequent monitoring needs and a fixed dosing regimen, which could enhance medication adherence. However, owing to unbalanced hemostasis, patients with cirrhosis have been excluded from most trials. Our case was portal hypertension without cirrhosis; therefore, DOACs or NOACs are not contraindicated after excluding antiphospholipid syndrome. For Crohn’s disease treatment, ustekinumab was more suitable than tumor necrosis factor inhibitors (anti-TNFα), as ustekinumab had low immunogenicity (generating antidrug antibodies), so it is feasible to avoid a combination of azathioprine and ustekinumab, in contrast to anti-TNF treatment, which necessitates such a combination [ 3 , 6 , 7 , 9 ]. Ustekinumab helped to eliminate the drug interactions of azathioprine and warfarin, note that warfarin was the only therapeutic option owing to the initial diagnosis of antiphospholipid syndrome. In addition, ustekinumab had the lowest rate of serious infections among the biological treatments [ 7 ]. Esophageal varices primary prophylaxis is not required, as primary prophylaxis must be initiated upon the detection of high-risk varices, such as small varices with red signs, medium or large varices regardless of Child–Pugh classification, or small varices in patients classified as Child–Pugh C [ 16 ]. It is possible to discontinue anticoagulant treatment after a year, whether or not portal vein recanalization occurs, because a longer period of anticoagulant treatment is unlikely to enhance the probability of recanalization if it does not occur after a year [ 4 ].

PVT symptoms are similar to the symptoms of an inflammatory bowel disease flare. Initial tests for antiphospholipid syndrome were falsely positive [ 17 ]. The wise choice of ustekinumab as the first-line biological treatment, which aided in weaning off azathioprine, led to avoiding azathioprine–warfarin interactions. Using DOACs or NOACs for the management of portal vein thrombosis in case of portal vein hypertension. Finally, the management of esophageal varices in the context of anticoagulant treatment. The use of portal vein Doppler ultrasound, particularly during flare-ups of inflammatory bowel disease, may contribute to the diagnosis and management of this uncommon complication.

Availability of data and materials

Not applicable.

Abbreviations

• Portal vein thrombosis
• Inflammatory bowel disease
• Crohn’s disease

C-reactive protein

International normalized ratio

K antagonists

Computed tomography

Subcutaneous

Antiphospholipid syndrome

Direct oral anticoagulants

Novel oral anticoagulants

Low molecular weight heparin

Hepatitis B surface antigen

Hepatitis B surface antibody

Hepatitis B core antibody

Naymagon L, Tremblay D, Zubizarreta N, Moshier E, Naymagon S, Mascarenhas J, Schiano T. The natural history, treatments, and outcomes of portal vein thrombosis in patients with inflammatory bowel disease. Inflamm Bowel Dis. 2021. https://doi.org/10.1093/ibd/izaa053 .

Article   PubMed   Google Scholar  

Satsangi J, Silverberg MS, Vermeire S, Colombel J. The Montreal classification of inflammatory bowel disease: controversies, consensus, and implications. Gut. 2006;55:749–53. https://doi.org/10.1136/gut.2005.082909 .

Article   CAS   PubMed   PubMed Central   Google Scholar  

Torres J, Bonovas S, Doherty G, Kucharzik T, Gisbert JP, Raine T, et al . ECCO Guidelines on therapeutics in Crohn’s disease: medical treatment. J Crohn Colitis. 2020;14:4–22. https://doi.org/10.1093/ecco-jcc/jjz180 .

Article   Google Scholar  

EASL Clinical Practice Guidelines. Vascular diseases of the liver. J Hepatol. 2016;64:179–202. https://doi.org/10.1016/j.jhep.2015.07.040 .

Kucharzik T, Ellul P, Greuter T, Rahier JF, Verstockt B, Abreu C, Albuquerque A, Allocca M, Esteve M, Farraye FA, Gordon H. ECCO guidelines on the prevention, diagnosis, and management of infections in inflammatory bowel disease. J Crohns Colitis. 2021;15:879–913. https://doi.org/10.1093/ecco-jcc/jjab052 .

Article   CAS   PubMed   Google Scholar  

Tektonidou MG, Andreoli L, Limper M, Amoura Z, Cervera R, Costedoat-Chalumeau N, et al . EULAR recommendations for the management of antiphospholipid syndrome in adults. Ann Rheum Dis. 2019;78:1296–304. https://doi.org/10.1136/annrheumdis-2019-215213 .

Sandborn WJ, Rebuck R, Wang Y, Zou B, Adedokun OJ, Gasink C, et al . Five-year efficacy and safety of ustekinumab treatment in Crohn’s disease: the IM-UNITI trial. Clin Gastroenterol Hepatol. 2022;20:578-590.e4. https://doi.org/10.1016/j.cgh.2021.02.025 .

Feagan BG, Sandborn WJ, Gasink C, Jacobstein D, Lang Y, Friedman JR, et al . Ustekinumab as induction and maintenance therapy for Crohn’s disease. N Engl J Med. 2016;375:1946–60. https://doi.org/10.1056/NEJMoa1602773 .

Harbord M, Annese V, Vavricka SR, Allez M, Barreiro-de Acosta M, Boberg KM, et al . The first European evidence-based consensus on extra-intestinal manifestations in inflammatory bowel disease. J Crohn Colitis. 2016;10:239–54. https://doi.org/10.1093/ecco-jcc/jjv213 .

Arvanitakis KD, Arvanitaki AD, Karkos CD, Zintzaras EΑ, Germanidis GS. The risk of venous thromboembolic events in patients with inflammatory bowel disease: a systematic review and meta-analysis. Ann Gastroenterol. 2021;34:680. https://doi.org/10.20524/aog.2021.0631 .

Article   PubMed   PubMed Central   Google Scholar  

Bernstein CN, Nugent Z, Singh H. Persistently high rate of venous thromboembolic disease in inflammatory bowel disease: a population-based study. Am J Gastroenterol. 2021. https://doi.org/10.14309/ajg.0000000000001237 .

Faye AS, Lee KE, Dodson J, Chodosh J, Hudesman D, Remzi F, et al . Increasing rates of venous thromboembolism among hospitalised patients with inflammatory bowel disease: a nationwide analysis. Alimentary Pharmacol Ther. 2022. https://doi.org/10.1111/apt.17162 .

Gordon H, Burisch J, Ellul P, Karmiris K, Katsanos K, Allocca M, et al . ECCO guidelines on extraintestinal manifestations in inflammatory bowel disease. J Crohn Colitis. 2023. https://doi.org/10.1093/ecco-jcc/jjad108 .

Passamonti F, Maffioli M, Caramazza D, Cazzola M. Myeloproliferative neoplasms: From JAK2 mutations discovery to JAK2 inhibitor therapies. Oncotarget. 2011;2:485–90.

Tefferi A, Vardiman JW. Classification and diagnosis of myeloproliferative neoplasms: the 2008 World Health Organization criteria and point-of-care diagnostic algorithms. Leukemia. 2008;22:14–22. https://doi.org/10.1038/sj.leu.2404955 .

Angeli P, Bernardi M, Villanueva C, Francoz C, Mookerjee RP, Trebicka J, et al . EASL Clinical Practice Guidelines for the management of patients with decompensated cirrhosis. J Hepatol. 2018;69:406–60. https://doi.org/10.1016/j.jhep.2018.03.024 .

Mallhi RS, Kushwaha N, Chatterjee T, Philip J. Antiphospholipid syndrome: a diagnostic challenge. Med J Armed Forces India. 2016;72:S31. https://doi.org/10.1016/j.mjafi.2016.05.001 .

Nguyen MHN, Sieloff EM, Tariq T, Bannon SF. Portal vein thrombosis as an initial presentation of Crohn’s disease. Clin J Gastroenterol. 2021;14:581–3. https://doi.org/10.1007/s12328-020-01307-0 .

Ma ASC, Ewing I, Murray CD, Hamilton MI. Hepatic portal venous gas and portal venous thrombosis following colonoscopy in a patient with terminal ileal Crohn’s disease. Case Rep. 2015;2015:bcr2014206854. https://doi.org/10.1136/bcr-2014-206854 .

Mian HS, Lawlor R. Venous thrombosis in inflammatory bowel disease. CMAJ. 2015;187:55–55. https://doi.org/10.1503/cmaj.140251 .

Maconi G, Bolzacchini E, Dell’Era A, Russo U, Ardizzone S, de Franchis R. Portal vein thrombosis in inflammatory bowel diseases: a single-center case series ☆ . J Crohn Colitis. 2012;6:362–7. https://doi.org/10.1016/j.crohns.2011.10.003 .

Georgescu E, Dumitrescu D, Ionescu R. Portal cavernoma in a patient with Crohn’s disease associated with factor V Leiden mutation and antiphospholipid syndrome. J Gastrointestin Liver Dis. 2010;19(4):449–52.

PubMed   Google Scholar  

McCabe JM, Mahadevan U, Vidyarthi A. An obscure harbinger. Difficult diagnosis of Crohn’s disease. Am J Med. 2009;122:516–8. https://doi.org/10.1016/j.amjmed.2009.02.003 .

Di Fabio F, Obrand D, Satin R, Gordon PH. Successful treatment of extensive splanchnic arterial and portal vein thrombosis associated with ulcerative colitis. Colorect Dis. 2009. https://doi.org/10.1111/j.1463-1318.2008.01704.x .

Racine A, Nahon S, Jouannaud V, Caugant H, Lesgourgues B. Portal vein thrombosis in a patient with quiescent Crohn’s disease associated with hyperhomocysteinemia and antiphospholipid antibody syndrome 1-yr after an ileocecal resection. Am J Gastroenterol. 2008;103:499–501. https://doi.org/10.1111/j.1572-0241.2007.01646_18.x .

Babyatsky MW, Keroack MD, Blake MA, Rosenberg ES, Mino-Kenudson M. Case records of the Massachusetts General Hospital. Case 35–2007. A 30-year-old man with inflammatory bowel disease and recent onset of fever and bloody diarrhea. N Engl J Med. 2007;357:2068–76. https://doi.org/10.1056/NEJMcpc079029 .

Palkovits J, Häfner M, Rand T, Vogelsang H, Kutilek M, Gangl A, et al . Portal vein thrombosis in ulcerative colitis complicated by bleeding from gastric varices. Inflamm Bowel Dis. 2007. https://doi.org/10.1002/ibd.20034 .

Brueck M, Runde T, Rauber K, Kramer W. Fibrinogengesteuerte Urokinaselyse einer Portal- und Mesenterialvenenthrombose bei akutem Schub einer Colitis ulcerosa. Dtsch Med Wochenschr. 2006;131:84–8. https://doi.org/10.1055/s-2006-924929 .

Shaked G, Czeiger D, Rozental A. Acute portal vein occlusion in a patient with Crohn’s disease. J Gastroenterol Hepatol. 2005;20:1472–3. https://doi.org/10.1111/j.1440-1746.2005.03981.x .

Guglielmi A, Fior F, Halmos O, Veraldi GF, Rossaro L, Ruzzenente A, et al . Transhepatic fibrinolysis of mesenteric and portal vein thrombosis in a patient with ulcerative colitis: a case report. World J Gastroenterol. 2005;11:2035–8. https://doi.org/10.3748/wjg.v11.i13.2035 .

Tomita J, Okada H, Mizuno M, Nasu J, Nishimura M, Nakamura S, et al . A case of ulcerative colitis successfully treated with low-dose warfarin for portal vein thrombosis after colectomy. Nihon Shokakibyo Gakkai Zasshi. 2005;102:25–30.

Valera JM, Nei LuC, Smok G, Fernández M, Regonesi C, Brahm J. Hepatic veno-occlusive disease, idiopathic ulcerative colitis and portal thrombosis. Report of one case. Rev Med Chil. 2004;132:1091–5. https://doi.org/10.4067/s0034-98872004000900010 .

Verna EC, Larghi A, Faddoul SG, Stein JA, Worman HJ. Portal vein thrombosis associated with Fusobacterium nucleatum septicemia in a patient with ulcerative colitis. J Clin Gastroenterol. 2004;38:611–2. https://doi.org/10.1097/00004836-200408000-00014 .

Mijnhout GS, Klinkenberg EC, Lycklama G, Linskens R, Meuwissen SGM. Sepsis and elevated liver enzymes in a patient with inflammatory bowel disease: think of portal vein thrombosis. Dig Liver Dis. 2004;36:296–300. https://doi.org/10.1016/j.dld.2003.10.018 .

Kluge S, Hahn KE, Lund CH, Gocht A, Kreymann G. Pylephlebitis with air in the portal vein system. An unusual focus in a patient with sepsis. Dtsch Med Wochenschr. 2003;128:1391–4. https://doi.org/10.1055/s-2003-40107 .

Junge U, Wienke J, Schüler A. Acute Budd-Chiari syndrome, portal and splenic vein thrombosis in a patient with ulcerative colitis associated with antiphospholipid antibodies and protein C deficiency. Z Gastroenterol. 2001;39:845–52. https://doi.org/10.1055/s-2001-17864 .

Hagimoto T, Seo M, Okada M, Shirotani T, Tanaka K, Tomita A, et al . Portal vein thrombosis successfully treated with a colectomy in active ulcerative colitis: report of a case. Dis Colon Rectum. 2001;44:587–90. https://doi.org/10.1007/BF02234334 .

Schäfer C, Zundler J, Bode CJ. Thrombolytic therapy in patients with portal vein thrombosis: case report and review of the literature. Eur J Gastroenterol Hepatol. 2000. https://doi.org/10.1097/00042737-200012100-00012 .

Farkas LM, Nelson RL, Abcarian H. A case of portal venous system thrombosis in ulcerative colitis. J Am Coll Surg. 2000;190:94. https://doi.org/10.1016/s1072-7515(99)00236-7 .

Baddley JW, Singh D, Correa P, Persich NJ. Crohn’s disease presenting as septic thrombophlebitis of the portal vein (pylephlebitis): case report and review of the literature. Am J Gastroenterol. 1999. https://doi.org/10.1111/j.1572-0241.1999.00959.x .

Yada S, Hizawa K, Aoyagi K, Hashizume M, Matsumoto T, Koga H, et al . Portal hypertensive gastropathy due to chronic portal vein occlusion in Crohn’s disease. Am J Gastroenterol. 1998. https://doi.org/10.1111/j.1572-0241.1998.424_e.x .

Zoepf T, Mayer D, Merckle E, Adler G, Beckh K. Portal vein thrombosis and multiple liver abscesses in Crohn’s disease—an example for successful conservative treatment. Z Gastroenterol. 1997;35:627–30.

CAS   PubMed   Google Scholar  

Tung JY, Johnson JL, Liacouras CA. Portal-mesenteric pylephlebitis with hepatic abscesses in a patient with Crohn’s disease treated successfully with anticoagulation and antibiotics. J Pediatr Gastroenterol Nutr. 1996;23:474.

Tsujikawa T, Ihara T, Sasaki M, Inoue H, Fujiyama Y, Bamba T. Effectiveness of combined anticoagulant therapy for extending portal vein thrombosis in Crohn’s disease. Report of a case. Dis Colon Rectum. 1996. https://doi.org/10.1007/BF02054451 .

Diehl SJ, Lehmann KJ, Manthe S. Georgi M [Septic portal vein thrombosis as a rare complication of Crohn disease with retroperitoneal abscess]. Aktuelle Radiol. 1996;6:99–101.

Miyazaki Y, Shinomura Y, Kitamura S, Hiraoka S, Tomoda K, Nezu R, et al. Portal vein thrombosis associated with active ulcerative colitis: percutaneous transhepatic recanalization. Am J Gastroenterol. 1995;90(9):1533–4.

Mathieu E, Fain O, Trinchet JC, Aurousseau MH, Stérin D, Thomas M. Portal vein thrombosis: a rare complication of Crohn disease. La Revue de Medecine Interne. 1994. https://doi.org/10.1016/s0248-8663(05)82504-4 .

Crowe A, Taffinder N, Layer GT, Irvine A, Nicholls RJ. Portal vein thrombosis in a complicated case of Crohn’s disease. Postgrad Med J. 1992;68:291–3. https://doi.org/10.1136/pgmj.68.798.291 .

Brinberg DE, Stefansson TB, Greicius FA, Kahlam SS, Molin C. Portal vein thrombosis in Crohn’s disease. Gastrointest Radiol. 1991;16:245–7. https://doi.org/10.1007/BF01887357 .

Reh TE, Srivisal S, Schmidt EH. Portal venous thrombosis in ulcerative colitis: CT diagnosis with angiographic correlation. J Comput Assist Tomogr. 1980;4:545–7. https://doi.org/10.1097/00004728-198008000-00029 .

Capron JP, Remond A, Lebrec D, Delamarre J, Dupas JL, Lorriaux A. Gastrointestinal bleeding due to chronic portal vein thrombosis in ulcerative colitis. Digest Dis Sci. 1979. https://doi.org/10.1007/BF01308436 .

Download references

Acknowledgements

Author information, authors and affiliations.

Gastroenterology Department, Damascus Hospital, Almujtahed Street, Damascus, Syria

Marouf Alhalabi, Duaa Nasri & Widad Aji

You can also search for this author in PubMed   Google Scholar

Contributions

MA contributed to the design and implementation, writing, reading, interpreting, and drafting the research. All authors contributed, revised, and approved the final manuscript.

Corresponding author

Correspondence to Marouf Alhalabi .

Ethics declarations

Ethics approval and consent to participate.

The institutional review board and research ethics committee of Damascus hospital had approved this case report with the Ethics Approval number: EAN:2023-17.

Consent for publication

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.

Competing interests

The authors declare that they have no competing interests.

Additional information

Publisher’s note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ . The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/ ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article.

Alhalabi, M., Nasri, D. & Aji, W. Portal vein thrombosis as extraintestinal complications of Crohn’s disease: a case report and review of literature. J Med Case Reports 18 , 246 (2024). https://doi.org/10.1186/s13256-024-04560-w

Download citation

Received : 10 October 2023

Accepted : 17 April 2024

Published : 14 May 2024

DOI : https://doi.org/10.1186/s13256-024-04560-w

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Ulcerative colitis
• Extraintestinal manifestations

Journal of Medical Case Reports

ISSN: 1752-1947

• Submission enquiries: Access here and click Contact Us
• General enquiries: [email protected]

• Case Report
• Open access
• Published: 14 May 2024

Motor polyradiculoneuropathy as an unusual presentation of neurobrucellosis: a case report and literature review

• Ahmad Alikhani 1 ,
• Noushin Ahmadi 1 ,
• Mehran Frouzanian 2 &
• Amirsaleh Abdollahi 2  

BMC Infectious Diseases volume  24 , Article number:  491 ( 2024 ) Cite this article

21 Accesses

Metrics details

Brucellosis, a zoonotic disease caused by Brucella species, poses a significant global health concern. Among its diverse clinical manifestations, neurobrucellosis remains an infrequent yet debilitating complication. Here, we present a rare case of neurobrucellosis with unusual presentations in a 45-year-old woman. The patient’s clinical course included progressive lower extremity weakness, muscle wasting, and double vision, prompting a comprehensive diagnostic evaluation. Notable findings included polyneuropathy, elevated brucella agglutination titers in both cerebrospinal fluid and blood, abnormal EMG-NCV tests, and resolving symptoms with antibiotic therapy. The clinical presentation, diagnostic challenges, and differentiation from other neurological conditions are discussed. This case underscores the importance of considering neurobrucellosis in regions where brucellosis is prevalent and highlights this rare neurological complication’s distinctive clinical and radiological features. Early recognition and appropriate treatment are crucial to mitigate the significant morbidity associated with neurobrucellosis.

Peer Review reports

Introduction

Brucellosis, caused by Brucella species, is an infectious ailment recognized by various names such as remitting, undulant, Mediterranean, Maltese, Crimean, and goat fever. Humans contract it through the consumption of unpasteurized milk and dairy products, undercooked meat, or skin contact with infected livestock [ 1 , 2 , 3 ]. Various Brucella species, including Brucella melitensis (primarily sourced from sheep and goats), Brucella abortus (found in cattle), Brucella suis (associated with pigs/hogs), and Brucella canis (linked to dogs), can lead to illness in humans [ 3 , 4 , 5 ]. While brucellosis in humans is rarely fatal, it can lead to disability [ 6 ]. Brucellosis ranks among the most prevalent zoonotic diseases, impacting approximately 500,000 individuals yearly [ 7 ]. The combined estimate for the prevalence of brucellosis was 15.53% [ 8 ].

Neurobrucellosis, a rare complication of systemic brucellosis, can occur in adult and pediatric cases [ 9 ], and can manifest at any stage of the disease. They can present in various clinical presentations such as meningitis, encephalitis, meningoencephalitis, myelitis, radiculopathy, polyneuropathy, stroke, cerebral venous thrombosis, and occasionally psychiatric symptoms [ 10 , 11 ]. Although the mortality rate is low, patients often experience persistent neurological issues following neurobrucellosis [ 12 ]. Studies suggest that around 20% of neurobrucellosis cases result in lasting neurological problems [ 13 ]. It is uncommonly considered in cases of meningoencephalitis or polyneuropathy, making it crucial for clinicians to have a high suspicion of it in patients displaying such symptoms, especially in endemic regions, to prevent severe clinical outcomes. In this study, we present a rare case of neurobrucellosis with unusual clinical presentations in a patient admitted to our center.

Case presentation

A 45-year-old female patient, with no prior medical history, presented to our center after enduring distal pain and weakness in her lower extremities for approximately 10 months. Over this period, the muscle weakness progressed, affecting proximal muscles of upper and lower limbs, and leading to a substantial weight loss of 25–30 kg despite maintaining appetite. Initially dismissive of the limb weakness and pain, the patient sought medical attention six months after symptom onset due to the worsening symptoms and gait impairment. Over the subsequent four months, she underwent multiple medical evaluations and tests, including a lumbar X-ray. Following these initial investigations and due to low serum vitamin D levels, vitamin D and calcium supplements were prescribed, and lumbar MRI were requested for further evaluation. (Table  1 )

Upon referral to an infectious disease specialist, the patient’s history of local dairy consumption and positive serologic test for brucellosis prompted treatment with rifampin and doxycycline. However, the patient’s condition deteriorated significantly five days after starting this treatment. She experienced severe gait disorder, lower extremity weakness, diplopia, and blurred vision that had gradually worsened over two weeks. Subsequently, she presented to our center for further assessment.

Upon admission, the patient was unable to stand even with assistance and exhibited diplopia. Cranial nerve examination revealed no abnormalities, except for the II, III, and IV cranial nerves, which could not be thoroughly examined due to the presence of diplopia. The patient tested negative for Kernig and Brudzinski signs. There were no palpable supraclavicular or inguinal lymph nodes. Physical examinations of the breast, axilla, lungs, heart, and abdomen were unremarkable. Muscle strength was reduced in the lower extremities, and deep tendon reflexes of the knee and Achilles were absent. The plantar reflex was non-responsive, and certain reflexes, including biceps, triceps, and brachioradialis, were absent despite normal movement of the upper extremities. Anorectal muscle tone and anal reflex were normal.

Further investigations included normal urinalysis and abdominal and pelvic ultrasound. Chest X-ray and brain CT were also ordered. Due to the patient’s refusal of lumbar puncture, a suspicion of neurobrucellosis led to the initiation of a three-drug regimen (Table  2 ); ceftriaxone 2 g IV twice daily, rifampin 600 mg PO daily, and doxycycline 100 mg PO twice daily. The ophthalmology consultation did not reveal any ocular pathology, and the neurologist ordered brain MRI and EMG-NCV tests. The patient’s brain MRI was unremarkable, but EMG-NCV showed sensory and motor polyneuropathy. Consequently, intravenous immunoglobulin (IVIG) therapy was initiated at a daily dose of 25 g. After five days, the patient consented to lumbar puncture, confirming the diagnosis of brucellosis. Co-trimoxazole 960 mg PO three times daily was added to her treatment regimen, and IVIG therapy continued for seven days. Following a 3-day course of IVIG treatment, the neuropathy symptoms showed significant improvement. By the seventh day, there was a notable enhancement in limb strength, particularly in the upper limbs, reaching a 2-point improvement. After undergoing three weeks of intravenous therapy, the patient transitioned to oral medication. Despite disagreement regarding the necessity of a second CSF examination, the patient was discharged with a prescription for doxycycline, rifampin, and cotrimoxazole. Upon discharge, the patient could walk with the aid of a walker. However, within a month, a slight limp persisted, and by the third-month post-discharge, all symptoms had resolved completely.

Brucellosis is widely spread globally, with more than half a million reported human cases annually [ 14 , 15 ]. Countries like Kenya, Yemen, Syria, Greece, and Eritrea have experienced high rates of brucellosis. The situation of brucellosis has shown signs of improvement in many epidemic regions. However, new areas with high occurrences of this disease continue to emerge, particularly in Africa and the Middle East, where the incidence of the disease varies [ 16 ]. Brucellosis is linked to various neurological complications collectively known as neurobrucellosis, which is an uncommon condition, and only a few cases have been reported globally [ 17 , 18 , 19 , 20 , 21 ]. Our patient exhibited muscle weakness, polyneuropathy, and inability to walk, which are often not regarded as indicative of a brucella infection by many physicians. While the diagnosis of neurobrucellosis can typically be confirmed through classical clinical signs, radiological examinations, and serological tests, patients might not always display typical symptoms, as observed in our case. Hence, in regions where the disease is prevalent, clinicians should maintain a high level of suspicion if patients do not show improvement with standard treatment. Additionally, the lack of awareness among healthcare professionals and limited access to advanced laboratory facilities can lead to misdiagnosis.

The frequent manifestations of neurobrucellosis include meningitis or meningoencephalitis. Typically, it starts with a sudden headache, vomiting, and altered mental state, which can progress to unconsciousness, with or without seizures [ 22 ]. Additionally, brucellosis can lead to several central nervous system issues such as inflammation of cerebral blood vessels, abscesses in the brain or epidural space, strokes, and cerebellar ataxia. Peripheral nerve problems may include nerve damage or radiculopathy, Guillain-Barré syndrome, and a syndrome resembling poliomyelitis [ 13 ]. Nevertheless, the patient exhibited no indications of seizures, brain hemorrhage, stroke, or focal neurological impairments. Instead, the observed symptoms were consistent with radiculopathy and muscular weakness.

In only 7% of neurobrucellosis cases, the peripheral nervous system is affected. Remarkably, our case falls within this rare category, adding to its unique and intriguing nature. Previous case studies have detailed polyradiculoneuropathies, manifesting as acute, subacute, or chronic forms [ 23 ]. Our patient’s condition aligns with chronic motor polyradiculopathy. Interestingly, some of these cases exhibit sensory deficits or resemble Guillain-Barré syndrome [ 23 , 24 ]. In a prior case study conducted by Abuzinadah and colleagues, a comparable case was described as a subacute motor polyradiculopathy. The patient exhibited gradual bilateral lower limb weakness over three weeks, eventually leading to loss of mobility within seven weeks. Brucella was isolated from the cerebrospinal fluid after a two-week incubation period, and high antibody titers were detected in the patient’s serum [ 23 ]. In another study led by Alanazi and colleagues, a 56-year-old man initially diagnosed with Guillain-Barré syndrome experienced worsening symptoms despite appropriate treatment. Following plasma exchange and antibiotics, his condition improved temporarily, only to relapse, raising suspicion of chronic inflammatory demyelinating polyneuropathy, and treatment with IVIG resulted in substantial improvement. Upon further investigation, he was diagnosed with brucellosis [ 24 ]. This highlights the importance of recognizing GBS-like symptoms in regions where brucellosis is prevalent, prompting clinicians to consider the possibility of brucellosis in their diagnosis.

While there are no established criteria for diagnosing neurobrucellosis [ 25 ], certain articles have suggested several methods for its diagnosis. These methods include the presence of symptoms aligning with neurobrucellosis, isolating brucella from cerebrospinal fluid (CSF) or detecting a positive brucella agglutination titer in CSF, observing lymphocytosis, elevated protein, and decreased glucose levels in CSF, or identifying specific diagnostic indicators in cranial imaging such as magnetic resonance imaging or computed tomography (MRI or CT) [ 13 , 26 , 27 , 28 ]. Neurobrucellosis does not present a distinct clinical profile or specific CSF characteristics. Imaging observations of neurobrucellosis fall into four categories: normal, inflammatory (indicated by granulomas and enhanced meninges, perivascular spaces, or lumbar nerve roots), alterations in white matter, and vascular changes [ 29 ]. We suspected neurobrucellosis based on the patient’s clinical symptoms, geographic correlation, high brucella agglutination test titers in both cerebrospinal fluid and blood, symptom resolution following treatment, and the exclusion of other common causes.

In Iran, one differential diagnosis often confused with brucellosis is tuberculosis, as both chronic granulomatous infectious diseases are prevalent here [ 30 , 31 ]. Neurobrucellosis and tuberculosis exhibit significant similarities in clinical symptoms, lab results, and neuroimaging findings. However, deep grey matter involvement and widespread white matter lesions seen in neuroimaging, resembling demyelinating disorders, appear to be distinctive to brucellosis [ 32 ]. There is a noticeable similarity in the clinical symptoms and laboratory findings of brucellosis and tuberculosis [ 33 ]. It is crucial to thoroughly eliminate the possibility of tuberculosis in any suspected or confirmed brucellosis cases before starting antibiotic treatment.

Due to the challenging nature of treating brucellosis and the likelihood of experiencing relapses, it is crucial to provide an extended course of treatment [ 27 ]. This treatment approach should involve a combination of antibiotics that can easily penetrate the cell wall and effectively reach the central nervous system [ 27 , 34 ]. Neurobrucellosis is treated with 3 to 6 months of combination therapy comprising doxycycline, rifampicin, and ceftriaxone or trimethoprim-sulfamethoxazole [ 35 ], similar to the treatment administered to our patient. For patients allergic to cephalosporins, quinolones are recommended, which are considered to be effective in treating brucellosis [ 36 , 37 ]. In complicated situations such as meningitis or endocarditis, streptomycin or gentamicin is administered in the initial 14 days of treatment, in addition to the previously mentioned regimen. Timely and proper treatment results in a positive prognosis, with a less than 1% fatality rate for such complex cases [ 17 , 38 ]. Our patient experienced a highly positive outcome following the prescribed therapy. Initially relying on a walker, a slight limp endured for a month, and by the third month after discharge, all symptoms completely disappeared.

The present study underscores the significance of considering neurobrucellosis as a potential diagnosis when evaluating muscle weakness and radiculopathy, especially in regions where the disease is prevalent. A comprehensive patient history, precise clinical examination, positive serology in blood or cerebrospinal fluid, imaging results, or cerebrospinal fluid analysis can contribute to establishing a conclusive diagnosis.

Data availability

The datasets generated and/or analysed during the current study are not publicly available due to our team’s privacy concerns but are available from the corresponding author on reasonable request.

Galińska EM, Zagórski J. Brucellosis in humans–etiology, diagnostics, clinical forms. Ann Agric Environ Med. 2013;20(2):233–8.

PubMed   Google Scholar  

Głowacka P, Żakowska D, Naylor K, Niemcewicz M, Bielawska-Drózd A. Brucella - Virulence factors, Pathogenesis and treatment. Pol J Microbiol. 2018;67(2):151–61.

Article   PubMed   PubMed Central   Google Scholar  

Khurana SK, Sehrawat A, Tiwari R, Prasad M, Gulati B, Shabbir MZ, et al. Bovine brucellosis - a comprehensive review. Vet Q. 2021;41(1):61–88.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Yagupsky P, Morata P, Colmenero JD. Laboratory diagnosis of human brucellosis. Clin Microbiol Rev. 2019;33(1).

Kurmanov B, Zincke D, Su W, Hadfield TL, Aikimbayev A, Karibayev T et al. Assays for identification and differentiation of Brucella species: a review. Microorganisms. 2022;10(8).

Franco MP, Mulder M, Gilman RH, Smits HL. Human brucellosis. Lancet Infect Dis. 2007;7(12):775–86.

Article   CAS   PubMed   Google Scholar  

Mantur BG, Amarnath SK, Shinde RS. Review of clinical and laboratory features of human brucellosis. Indian J Med Microbiol. 2007;25(3):188–202.

Khoshnood S, Pakzad R, Koupaei M, Shirani M, Araghi A, Irani GM, et al. Prevalence, diagnosis, and manifestations of brucellosis: a systematic review and meta-analysis. Front Vet Sci. 2022;9:976215.

Dhar D, Jaipuriar RS, Mondal MS, Shunmugakani SP, Nagarathna S, Kumari P et al. Pediatric neurobrucellosis: a systematic review with case report. J Trop Pediatr. 2022;69(1).

Mahajan SK, Sharma A, Kaushik M, Raina R, Sharma S, Banyal V. Neurobrucellosis: an often forgotten cause of chronic meningitis. Trop Doct. 2016;46(1):54–6.

Article   PubMed   Google Scholar  

Dreshaj S, Shala N, Dreshaj G, Ramadani N, Ponosheci A. Clinical manifestations in 82 neurobrucellosis patients from Kosovo. Mater Sociomed. 2016;28(6):408–11.

Gul HC, Erdem H, Bek S. Overview of neurobrucellosis: a pooled analysis of 187 cases. Int J Infect Dis. 2009;13(6):e339–43.

Guven T, Ugurlu K, Ergonul O, Celikbas AK, Gok SE, Comoglu S, et al. Neurobrucellosis: clinical and diagnostic features. Clin Infect Dis. 2013;56(10):1407–12.

Alkahtani AM, Assiry MM, Chandramoorthy HC, Al-Hakami AM, Hamid ME. Sero-prevalence and risk factors of brucellosis among suspected febrile patients attending a referral hospital in southern Saudi Arabia (2014–2018). BMC Infect Dis. 2020;20(1):26.

Pappas G, Papadimitriou P, Akritidis N, Christou L, Tsianos EV. The new global map of human brucellosis. Lancet Infect Dis. 2006;6(2):91–9.

Liu Z, Gao L, Wang M, Yuan M, Li Z. Long ignored but making a comeback: a worldwide epidemiological evolution of human brucellosis. Emerg Microbes Infect. 2024;13(1):2290839.

Naderi H, Sheybani F, Parsa A, Haddad M, Khoroushi F. Neurobrucellosis: report of 54 cases. Trop Med Health. 2022;50(1):77.

Farhan N, Khan EA, Ahmad A, Ahmed KS. Neurobrucellosis: a report of two cases. J Pak Med Assoc. 2017;67(11):1762–3.

Karsen H, Tekin Koruk S, Duygu F, Yapici K, Kati M. Review of 17 cases of neurobrucellosis: clinical manifestations, diagnosis, and management. Arch Iran Med. 2012;15(8):491–4.

Türel O, Sanli K, Hatipoğlu N, Aydoğmuş C, Hatipoğlu H, Siraneci R. Acute meningoencephalitis due to Brucella: case report and review of neurobrucellosis in children. Turk J Pediatr. 2010;52(4):426–9.

Guney F, Gumus H, Ogmegul A, Kandemir B, Emlik D, Arslan U, et al. First case report of neurobrucellosis associated with hydrocephalus. Clin Neurol Neurosurg. 2008;110(7):739–42.

Corbel MJ. Brucellosis: an overview. Emerg Infect Dis. 1997;3(2):213–21.

Abuzinadah AR, Milyani HA, Alshareef A, Bamaga AK, Alshehri A, Kurdi ME. Brucellosis causing subacute motor polyradiculopathy and the pathological correlation of pseudomyopathic electromyography: a case report. Clin Neurophysiol Pract. 2020;5:130–4.

Alanazi A, Al Najjar S, Madkhali J, Al Malik Y, Al-Khalaf A, Alharbi A. Acute Brucellosis with a Guillain-Barre Syndrome-Like Presentation: a Case Report and Literature Review. Infect Dis Rep. 2021;13(1):1–10.

Raina S, Sharma A, Sharma R, Bhardwaj A, Neurobrucellosis. A Case Report from Himachal Pradesh, India, and review of the literature. Case Rep Infect Dis. 2016;2016:2019535.

PubMed   PubMed Central   Google Scholar  

McLean DR, Russell N, Khan MY. Neurobrucellosis: clinical and therapeutic features. Clin Infect Dis. 1992;15(4):582–90.

Bouferraa Y, Bou Zerdan M, Hamouche R, Azar E, Afif C, Jabbour R. Neurobrucellosis: brief review. Neurologist. 2021;26(6):248–52.

Aygen B, Doğanay M, Sümerkan B, Yildiz O, Kayabaş Ü. Clinical manifestations, complications and treatment of brucellosis: a retrospective evaluation of 480 patients. Méd Mal Infect. 2002;32(9):485–93.

Article   Google Scholar  

Kizilkilic O, Calli C, Neurobrucellosis. Neuroimaging Clin N Am. 2011;21(4):927–37. ix.

Chalabiani S, Khodadad Nazari M, Razavi Davoodi N, Shabani M, Mardani M, Sarafnejad A, et al. The prevalence of brucellosis in different provinces of Iran during 2013–2015. Iran J Public Health. 2019;48(1):132–8.

Doosti A, Nasehi M, Moradi G, Roshani D, Sharafi S, Ghaderi E. The pattern of tuberculosis in Iran: A National Cross-sectional Study. Iran J Public Health. 2023;52(1):193–200.

Rajan R, Khurana D, Kesav P. Deep gray matter involvement in neurobrucellosis. Neurology. 2013;80(3):e28–9.

Dasari S, Naha K, Prabhu M. Brucellosis and tuberculosis: clinical overlap and pitfalls. Asian Pac J Trop Med. 2013;6(10):823–5.

Ko J, Splitter GA. Molecular host-pathogen interaction in brucellosis: current understanding and future approaches to vaccine development for mice and humans. Clin Microbiol Rev. 2003;16(1):65–78.

Zhao S, Cheng Y, Liao Y, Zhang Z, Yin X, Shi S. Treatment efficacy and risk factors of Neurobrucellosis. Med Sci Monit. 2016;22:1005–12.

Hasanain A, Mahdy R, Mohamed A, Ali M. A randomized, comparative study of dual therapy (doxycycline-rifampin) versus triple therapy (doxycycline-rifampin-levofloxacin) for treating acute/subacute brucellosis. Braz J Infect Dis. 2016;20(3):250–4.

Falagas ME, Bliziotis IA. Quinolones for treatment of human brucellosis: critical review of the evidence from microbiological and clinical studies. Antimicrob Agents Chemother. 2006;50(1):22–33.

Budnik I, Fuchs I, Shelef I, Krymko H, Greenberg D. Unusual presentations of pediatric neurobrucellosis. Am J Trop Med Hyg. 2012;86(2):258–60.

Download references

This research did not receive any funding or financial support.

Author information

Authors and affiliations.

Infectious Diseases Department and Antimicrobial Resistance Research Center and Transmissible Diseases Institute, Mazandaran University of Medical Sciences, Sari, Iran

Ahmad Alikhani & Noushin Ahmadi

Student Research Committee, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran

Mehran Frouzanian & Amirsaleh Abdollahi

You can also search for this author in PubMed   Google Scholar

Contributions

A.A oversaw and treated the case, including the entire revision process. N.A. contributed to the article’s composition. M.F. authored the discussion section, along with the complete revision. AS.A. played a role in crafting the case report discussion and participated in the entire revision process.

Corresponding author

Correspondence to Amirsaleh Abdollahi .

Ethics declarations

Ethics approval and consent to participate.

In adherence to ethical standards, rigorous protocols were followed to obtain approval from the relevant ethics committee and secure informed consent from all participants involved in the study.

Consent for publication

informed consent was obtained from the patient for both study participation AND publication of identifying information/images in an online open-access publication.

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ . The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/ ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article.

Alikhani, A., Ahmadi, N., Frouzanian, M. et al. Motor polyradiculoneuropathy as an unusual presentation of neurobrucellosis: a case report and literature review. BMC Infect Dis 24 , 491 (2024). https://doi.org/10.1186/s12879-024-09365-2

Download citation

Received : 04 December 2023

Accepted : 29 April 2024

Published : 14 May 2024

DOI : https://doi.org/10.1186/s12879-024-09365-2

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Neurobrucellosis
• EMG-NCV tests
• Polyradiculoneuropathy
• Antibiotic therapy
• Intravenous immunoglobulin therapy
• Zoonotic disease
• Gait disorder
• Lower extremity weakness
• Blurred vision

BMC Infectious Diseases

ISSN: 1471-2334

• Submission enquiries: [email protected]
• General enquiries: [email protected]

CASE REPORT article

Eosinophilic granulomatous polyangiitis with central nervous system involvement in children: a case report and literature review.

• Department of Pediatric Nephrology, Rheumatology, and Immunology, The Affiliated Hospital of Qingdao University, Qingdao, China

Objective: To explore the clinical characteristics and treatment outcomes of children with central nervous system (CNS) involvement in eosinophilic granulomatosis with polyangiitis (EGPA).

Methods: A child who presented with EGPA complicated by CNS involvement was admitted to our hospital in June 2023. The clinical features were analyzed retrospectively, and relevant literatures were reviewed to provide a comprehensive overview of this condition.

Results: A ten-year-old girl, who had a history of recurrent cough and asthma accompanied by peripheral blood eosinophilia for eight months, was admitted to our hospital. On admission, spotted papules were visible on her hands and feet, bilateral pulmonary rales were audible. The laboratory examination revealed that the proportion of eosinophils (EOS) exceeded 10% of white blood cells, the anti-neutrophil cytoplasmic antibody (MPO-ANCA) was positive, the immunoglobulin G level was 15.80g/L, and the immunoglobulin E level was greater than 2500.00IU/mL. The imaging examination showed multiple patchy and nodular high-density shadows in both lungs as well as sinusitis. Pulmonary function tests indicated moderate ventilation and diffusion dysfunction. Bone marrow cytology demonstrated a significant increase in the proportion of eosinophils. Skin pathology confirmed leukocytoclastic vasculitis. During the hospitalization, the child had a convulsion. The magnetic resonance imaging (MRI) scan of the brain showed multiple abnormal signal shadows in the bilateral cerebral cortex and the electroencephalogram (EEG) showed epileptic waves. Following the administration of methylprednisolone pulse therapy in combination with cyclophosphamide treatment, her cough and asthma resolved, the skin rash disappeared without any further convulsions. We found that only a young EGPA patient with CNS involvement had been previously reported. The previously reported case began with long-term fever, weight loss, and purpuric rash. Both patients responded well to treatment with glucocorticoids and cyclophosphamide, experiencing significant improvement in their clinical symptoms and normalization of their peripheral blood eosinophils.

Conclusion: The diagnosis of EGPA in children can be challenging. When a child is affected by EGPA, it is essential to remain vigilant for signs of CNS involvement. The treatment with glucocorticoids and cyclophosphamide is effective in managing EGPA in children.

1 Introduction

Eosinophilic granulomatosis with polyangiitis is a rare autoimmune vasculitis that primarily affects small- to medium-sized blood vessels ( 1 ). The onset of EGPA is generally observed between the ages of 25 and 50, with a reported prevalence among adults ranging from 10 to 13 per million. Nevertheless, EGPA can also manifest during childhood, carrying a notable attendant morbidity and mortality ( 2 ). Characterized by eosinophilia, granulomatous inflammation, and necrotizing vasculitis, it typically manifests with a wide range of symptoms including asthma, eosinophilia, and systemic vasculitis. Furthermore, it has the potential to affect numerous organs, including the kidneys, heart, digestive tract, and nervous system. Notably, in EGPA, peripheral nervous system involvement is more prevalent, whereas central nervous system involvement occurs less frequently. The pathophysiology of EGPA involves the dysregulation of the immune system, specifically the activation of eosinophils, which trigger inflammation and tissue damage in affected organs. Recent studies have unequivocally established the significance of ANCA in tissue damage from a clinicopathological perspective ( 2 ). The diagnosis of the disease relies on a combination of clinical findings, laboratory tests, and histopathological examination. Treatment typically involves the use of immunosuppressive drugs and corticosteroids, aimed at suppressing the overactive immune system and reducing inflammation ( 3 ). In this study, we retrospectively analyzed the clinical characteristics of a pediatric case of EGPA complicated by CNS involvement.

2 Case presentations

A ten-year-old girl, who had a history of recurrent cough and asthma accompanied by peripheral blood eosinophilia for eight months, was admitted to our hospital in June 2023. In January and March 2023, she was hospitalized at another hospital due to recurrent cough and asthma. During the period, multiple blood tests revealed a significant increase in eosinophil count and IgE levels. MPO-ANCA was positive while the antinuclear antibodies profile was negative. Allergen testing confirmed strong sensitization to dust mites. Chest CT scan reveals augmented thickness and density of the pulmonary trachea, numerous ground-glass opacities and nodular shadows scattered throughout the lungs, as well as enhanced bronchial wall thickness. Nasal sinus CT scan revealed acute sinusitis. Pulmonary function test indicated moderate ventilation and diffusion dysfunction. Bone marrow cytology showed hyperplastic bone marrow with a notable increase in eosinophil proportion. Lung alveolar lavage fluid examination did not detect pathogenic bacteria. Genetic testing through whole exome sequencing did not identify any pathogenic mutations associated with the clinical phenotype. During the second hospitalization, a transient red rash appeared on her left wrist. Following treatment with anti-infective agents, glucocorticoids, nebulization, her eosinophil count normalized and the rash disappeared. After discharge, she was prescribed oral prednisone acetate, which was gradually tapered.

Eleven days prior to admission, she experienced unprovoked intermittent coughing, accompanied by yellowish and purulent sputum. The cough, which was particularly severe during the night, was accompanied by wheezing and dyspnea. Additional symptoms included nasal congestion and yellowish loose stools. Notably, the eosinophil count in the blood routine examination at another hospital was once again elevated. Despite treatment with azithromycin for anti-infection, the child’s condition did not improve. Five days prior to admission, she developed a fever accompanied by red rashes on the extensor surfaces of the feet and hands. The cough intensified, and there was hemoptysis, which was pinkish and streaky in nature. The hemoptysis episodes occurred at regular intervals of 10–20 minutes. The child had previously been in excellent health and had no significant personal history. Her father had a history of allergic rhinitis, and her mother had an allergic constitution.

On admission, she revealed a weight of 29kg (P25-P50), a height of 146cm (P75-P90), a temperature of 36.2°C, a heart rate of 135 beats per minute, a respiratory rate of 40 beats per minute, the blood pressure of 95/60mmHg, and the oxygen saturation (SP02) ranging between 93% and 94%. She was conscious but in a poor mental state. Spotted papules were visible on her hands and feet, which were partially ulcerated and scabbed, accompanied by pain ( Figure 1A ). Additionally, pulmonary rales were audible bilaterally. The abdomen was soft, with a 2cm indentation under the right rib cage of the liver. The cardiac and neurologic examinations were unremarkable.

Figure 1 (A) Foot rash, partially ulcerated and scabbed. (B, C) Before treatment, the HRCT scan of the chest showed multiple patchy and nodular lesions with unclear boundaries, indicating high-density shadows in both lungs. And multiple enlarged lymph nodes were observed in the mediastinum and bilateral hilar regions. (D) Before treatment, the CT plain scan of the paranasal sinuses revealed a notable thickening of the mucosa in the bilateral maxillary, ethmoid, sphenoid, and frontal sinuses. (E) Before treatment, the MRI scan of the brain showed multiple abnormal signal shadows in the bilateral cerebral cortex. (F) Before treatment, the MRA revealed moderate to severe stenosis in the middle cerebral artery segment M2 of the left middle cerebral artery.

The laboratory tests showed white blood cell count of 13.66×10 9 /L (4.3×10 9 -11.3×10 9 ), lymphocyte count of 1.27×10 9 /L (1.5×10 9 -4.6×10 9 ), eosinophil count of 4.11×10 9 /L (0.00×10 9 -0.68×10 9 ), platelet count of 314×10 9 /L (167×10 9 -453×10 9 ), hemoglobin of 118g/L (118–156), C-reactive protein of 67.68mg/L (0–5); erythrocyte sedimentation rate of 43.00mm/60min (0–20), procalcitonin of 0.181ng/mL (<0.05), albumin of 23.5g/L (39–54), D-dimer of 7310ng/mL (0–500), ferritin of 438ng/ml (13–84). The blood culture and sputum culture were negative, and the blood coagulation, liver function, kidney function, myocardial enzymes, urine, and stool samples were all within normal limits. The immunological assessment revealed that the immunoglobulin G level was 15.80g/L, while the immunoglobulin E level was significantly elevated at >2500.00IU/mL. Detailed lymphocyte subset analysis reveals lymphocytes constitute 3.98% (11.4%-57%) of white blood cells, and among lymphocytes, T lymphocytes represent 63.71% (53.7%-82.8%). Helper T lymphocytes, CD4+ naive T cells and CD4+ effector T cells account for 60.55% (46.2%-78%), 26.39% (7.2%-68.9%), 24.56% (0.44%-6.06%) of total T lymphocytes, respectively. Plasmablasts represent 0.29% (1.9%-23.7%) of B lymphocytes. Other lymphocyte subsets such as NK cells, CD4+ central memory T cells, regulatory T cells, CD8+ T cells, double negative T cells, B lymphocytes, and dendritic cells are generally normal. The tests for antinuclear antibody, complement, ASO and RF were all negative. The aetiological examination indicated that the five respiratory pathogens, Mycoplasma pneumoniae, fungal G test, fungal GM test, and tuberculosis infection T cell were all negative.

The high-resolution chest computed tomography (HRCT) imaging revealed multiple patchy and nodular lesions with unclear boundaries, indicating high-density shadows in both lungs ( Figure 1B ). Additionally, multiple enlarged lymph nodes were observed in the mediastinum and bilateral hilar regions ( Figure 1C ), and a small amount of pleural effusion was present on the right side. The CT plain scan of the paranasal sinuses revealed a notable thickening of the mucosa in the bilateral maxillary, ethmoid, sphenoid, and frontal sinuses ( Figure 1D ). Within the sinus cavities, there were scattered patches of low-density lesions, and no significant signs of bone destruction were detected in the sinus walls. Pulmonary function tests indicated moderate ventilation and diffusion dysfunction. Bone marrow cytology demonstrated a significant increase in the proportion of eosinophils. Electrocardiogram displayed sinus rhythm and irregular sinus rhythm. Echocardiogram revealed mild mitral and tricuspid valve regurgitation.

After admission, the child was given piperacillin sodium and tazobactam sodium for anti-infection, nebulized for cough and asthma. However, on the second day of hospitalization, she continued to experience fever, coughing, hemoptysis, and labored breathing. Even under oxygen inhalation, her oxygenation remained inadequate. Therefore, the child was transferred to the Pediatric Intensive Care Unit (PICU) for tracheal intubation and ventilator support treatment under sedation and analgesia. Meanwhile, meropenem was upgraded for anti-infection, etamsylate and hemocoagulase were given for hemostasis.

Then she underwent bronchoscopy, revealing significant inflammatory and nodular changes in the bronchial mucosa under microscopic examination. Lung lavage fluid metagenomic test came back negative, while the culture suggested EB virus infection. Cytological classification showed neutrophils at 23.00% (<2%) and eosinophils at 13.00% (<1%). Therefore, we enhanced the etiological examination of EB. The EB virus capsid antigen IgM was 8.19AU/mL (<3), and EB virus DNA was 2.03e+003 (≤5.0e+003). Subsequently, we added ganciclovir antiviral therapy to the treatment plan. Furthermore, the skin pathological examination of the left ankle showed a reticulated pattern of hyperkeratosis, accompanied by necrosis in the central epidermis. In the superficial and middle layers of the dermis, fibrinoid necrosis is observed in the blood vessel walls, concurrent with neutrophil infiltration. Numerous neutrophils and eosinophils are visible infiltrating the areas surrounding the blood vessels, while erythrocyte extravasation and nuclear dust are also apparent. Notably, no distinct granulomatous structure is evident, and the overall changes are indicative of leukocytoclastic vasculitis ( Figure 2A ). The pathological examination of the lung tissue biopsy indicated the presence of chronic suppurative inflammation, accompanied by fibrous tissue proliferation and fibrosis ( Figures 2B, C ).

Figure 2 (A) Before treatment, the skin pathological examination of the left ankle showed a reticulated pattern of hyperkeratosis, accompanied by necrosis in the central epidermis. In the superficial and middle layers of the dermis, fibrinoid necrosis is observed in the blood vessel walls, concurrent with neutrophil infiltration. Numerous neutrophils and eosinophils are visible infiltrating the areas surrounding the blood vessels, while erythrocyte extravasation and nuclear dust are also apparent. Notably, no distinct granulomatous structure is evident, and the overall changes are indicative of leukocytoclastic vasculitis. (B, C) Before treatment, the pathological examination of the lung tissue biopsy indicated the presence of chronic suppurative inflammation, accompanied by fibrous tissue proliferation and fibrosis.

The patient, a school-age girl, has a known history of recurrent asthma. Over the course of the illness, she has developed skin and lung involvement. Her peripheral blood eosinophil count has repeatedly been found to be more than 10%, and a sinus CT scan has demonstrated sinusitis. After using the clinical diagnostic criteria established by the American College of Rheumatology in 1990 ( 4 ), we confirmed the diagnosis of EGPA. After obtaining a clear diagnosis, we administered a methylprednisolone pulse therapy (500mg for 3 days followed by 750mg for 2 days) and cyclophosphamide (300mg for 2 days) to effectively treat the condition. In addition, we administered piperacillin tazobactam to combat infections. Following these treatments, her temperature normalized, coughing, wheezing, and hemoptysis symptoms resolved, and the rash showed signs of improvement.

On the seventh day of hospitalization, the child had a convulsion once, with both eyes exhibiting an upward gaze, and a blood pressure of 125/72mmHg. The child’s consciousness remains unknown while sedated. The EEG showed epileptic waves. We have perfected the lumbar puncture procedure and did not detect any abnormalities in the cerebrospinal fluid routine, biochemistry, immunoglobulin, bacterial culture, and smear. MRI scan of the brain showed multiple FLAIR hyperintensities in the bilateral cerebral cortex ( Figure 1E ). The magnetic resonance angiography (MRA) revealed moderate to severe stenosis in the middle cerebral artery segment M2 of the left middle cerebral artery ( Figure 1F ), while the magnetic resonance venography (MRV) showed no significant abnormalities. To control the epileptic seizures, she was administered levetiracetam. After treatment, the child no longer experienced seizures.

At the follow-up review conducted one month following discharge, her peripheral blood eosinophil count returned to normal levels. Chest CT scans revealed significant improvement in lung inflammation ( Figures 3A, B ), pulmonary function test showed mild ventilation-diffusion dysfunction. And the cranial MRI showed a reduction in the abnormal signal intensity in the bilateral cerebral cortex compared to the previous scan ( Figure 3C ) while the cranial MRA was unremarkable ( Figure 3D ). The patient continues to visit the outpatient department for regular follow-up appointments, adjust the dosage and frequency of drug administration based on laboratory and imaging test results. Currently, she is receiving maintenance treatment with 6 rounds of monthly intravenous cyclophosphamide already completed.

Figure 3 (A, B) After treatment, the chest CT scans revealed significant improvement in lung inflammation and no obvious enlarged lymph nodes were seen in the mediastinum and bilateral hilar. (C) After treatment, the cranial MRI showed a reduction in the abnormal signal intensity in the bilateral cerebral cortex compared to the previous scan. (D) After treatment, there were no markedly abnormal findings in cranial MRA.

Using the search terms “eosinophilic granulomatosis with polyangiitis (EGPA)/Churg-Strauss syndrome”, “central nervous system” and “child” to search the China National Knowledge Infrastructure (CNKI), Wanfang database, and Chinese Biomedical Literature Database (up to December 2023), no reports of children were found. All reported cases were adults and the common clinical manifestations of the CNS were cerebral infarction or ischemia, subarachnoid hemorrhage, and cerebral hemorrhage. When we searched the PubMed database using the same search terms, we retrieved one relevant case ( 5 ). The patient, a 14-year-old boy, presented with a protracted fever, weight loss, muscle pain, joint pain, and a purpuric rash. He subsequently developed finger numbness, sinusitis, testicular pain, lung infiltration, asthma, and pericardial effusion. Laboratory tests revealed that eosinophils accounted for 58% of his peripheral blood count. The skin biopsy results indicated eosinophilic granulocytic infiltration necrotizing vasculitis. Following initial treatment with glucocorticoids and cyclophosphamide, the patient’s condition improved. However, during the course of his illness, he developed cerebral vasculitis secondary to epilepsy, and ultimately, hypoxemia and cardiac arrest triggered by severe asthma led to his demise. The case we reported is the first known instance of pediatric CNS involvement in China to date.

3 Discussion

EGPA is a multifaceted disease characterized by chronic rhinosinusitis, chronic sinusitis, asthma, and elevated levels of eosinophils in the peripheral blood. It was first described by pathologists J.Churg and L.Strauss in 1951, also known as the Churg-Strauss syndrome. EGPA is a rare disorder, with an annual incidence rate ranging from 0.5 to 6.8 per million individuals ( 6 ). It can affect individuals of all ages, with the median age of onset typically ranging from 38 to 54. There are no significant racial, familial, or gender disparities associated with EGPA. Additionally, few cases have been reported in children ( 7 ).

The cause of EGPA remains unknown, but it is thought to be associated with environmental and genetic factors. The primary mechanism behind the development of EGPA is caused by EOS infiltration and ANCA-induced damage to the vascular endothelium. Notably, approximately 70% of patients have a history of allergic rhinitis, and the onset often linked to asthma. Comprehensive examinations reveal elevated levels of EOS in the peripheral blood and tissues, along with increased IgE levels, indicating that EGPA may be a form of allergic or hypersensitivity disease ( 8 ).

EGPA is distinguished by eosinophilic infiltration and vasculitis, presenting with a diverse array of vascular-related clinical symptoms. Vasculitis primarily targets small-to-medium-sized vessels, resulting in a spectrum of issues linked to blood vessel dysfunction. Respiratory involvement, particularly affecting the lungs, is a prominent feature of EGPA. Additionally, patients may exhibit cutaneous vasculitis due to inflammation and necrosis in skin vessels. Cardiovascular, gastrointestinal, and nervous system involvements are also possible ( 2 ). A significant proportion of EGPA patients, up to 75%, experience peripheral neuropathy, often manifesting as polyneuropathy. In some instances, cranial nerves may also be implicated, though central nervous system involvement remains comparatively uncommon. And in a recent systematic analysis of 33 children with EGPA by Zwerina, it was observed that female patients were in the majority ( 9 ). Notably, when compared to adults, children tend to have more severe involvement of the heart and lungs, while the peripheral nerves and skeletal muscles are less.

The clinical features of EGPA are typically divided into three distinct stages: the prodromal phase, the vasculitis phase, and the extravascular granuloma phase. During the prodromal phase, patients typically exhibit atopic diseases with eosinophilia being most prevalent in the peripheral blood, lung and gastrointestinal tract. The vasculitis phase is characterized by the presence of systemic small-to-medium vessel vasculitis. Skin involvement is a frequent feature of this phase, affecting between 1/2 and 2/3 of EGPA patients. This involvement typically manifests as tender subcutaneous nodules on the extensor surfaces of the arms, hands and legs, as well as petechial or ecchymotic skin lesions. The heart is also often observed during this phase and represents one of the severe manifestations. The extravascular granuloma phase is the final stage, during which patients may develop granulomatous lesions in the nose, lungs, and intestines.

The diagnostic criteria for EGPA primarily rely on the clinical diagnostic criteria established by the American College of Rheumatology in 1990 ( 4 ). It includes: (1) a history of asthma (2) peripheral blood eosinophilia with a proportion exceeding 10% of white blood cells (3) involvement of paranasal sinuses (4) transient pulmonary infiltrates (5) neuropathy affecting single or multiple nerves (6) pathological confirmation of extravascular eosinophil infiltration. A patient who meets four or more could be diagnosed with EGPA. The lung and the skin are most commonly affected while EGPA can impact any system, including the cardiovascular, gastrointestinal, renal, and central nervous system. In the case we are reporting, the patient demonstrated involvement of the lung, skin and CNS during the course of the illness. Her peripheral blood eosinophil counts repeatedly exceeded 10%, and cranial imaging indicated sinusitis, fulfilling the diagnostic criteria. The time from onset to diagnosis was 8 months, exhibiting characteristics such as recurrent illness, multiple affected organs, and a severe condition compared to many adult EGPA cases.

The involvement of the CNS in EGPA is characterized by clinical manifestations that cannot be attributed to metabolic encephalopathy or other causes. It is estimated that approximately 70% of adult EGPA patients experience neurological involvement, although the CNS is less commonly affected ( 10 ). The involvement of the CNS mainly manifests as ischemic lesions, intracranial hemorrhage or subarachnoid hemorrhage, cranial nerve palsy and vision loss ( 11 ). The pathogenesis may be associated with secondary cerebral vasculitis and eosinophilic infiltration. Suying Liu et al. conducted a study on 110 EGPA patients aged between 19 and 80, and found that 17.3% had involvement of the CNS. The most common manifestation was ischemic lesions (63.2%), followed by reversible posterior encephalopathy syndrome (PRES) (36.8%) ( 12 ). And age, disease duration, and fever are potential independent risk factors for CNS involvement.

EGPA-associated PRES is characterized by patients presenting with typical acute neurological symptoms, along with radiological abnormalities of reversible vasogenic brain edema. This condition is often accompanied by seizures, encephalopathy, headache, and visual disturbances in the context of EGPA. The precise mechanism of PRES remains unclear, and it may be caused by changes in brain autoregulation due to the involvement of two mechanisms: hypertension and endothelial injury ( 13 , 14 ). During the course of the patient’s illness, seizures occurred, blood pressure increased significantly compared to when the patient was admitted, cranial MR imaging demonstrated PRES manifestations, and MRA revealed cerebral artery stenosis. Consequently, a comprehensive evaluation encompassing the child’s clinical presentation, radiological findings, and response to therapy led to the conclusion that the patient was suffering from EGPA complicated by CNS involvement, manifesting as PRES and cerebrovascular stenosis.

At present, there are no confirmed laboratory indicators for EGPA. Some studies have shown that adults with EGPA who are ANCA-positive are more likely to exhibit clinical manifestations such as weight loss, ear, nose, and throat lesions, as well as peripheral neuropathy. While ANCA-negative individuals are more prone to tissue damage in the heart and lungs. In this particular case, the child was ANCA-positive and presented with symptoms such as fever, rash, involvement of the gastrointestinal tract, lungs, and nervous system. However, in Eleftheriou’s pediatric series of EGPA in the UK, none of the children tested positive for ANCA ( 15 ). Given the limited number of pediatric EGPA cases, it remains uncertain whether there is a correlation between clinical manifestations and ANCA in children.

The treatment of EGPA involves a multidisciplinary approach tailored to the specific needs of each patient. The main goals of therapy are to control inflammation, prevent organ damage, and improve quality of life. Systemic glucocorticoids continue to serve as the cornerstone of treatment, effectively suppressing inflammation and managing symptoms. Patients with severe disease require pulsed intravenous glucocorticoid treatment, typically administered as daily methylprednisolone pulses ranging from 500 to 1,000 mg each over a three-day period, with a maximum cumulative dose of 3 grams. Subsequently, high-dose oral glucocorticoids should be prescribed, such as 0.75 to 1 mg/kg per day, to maintain effective therapy ( 3 ). In severe cases, particularly when the central nervous system, heart, kidneys, or digestive tract are affected, immunosuppressive agents such as cyclophosphamide or methotrexate may be prescribed. These agents aim to modulate immune system activity and safeguard blood vessels and organs from further harm. For younger patients with involvement of the nervous system and myocardium, the use of high-dose intravenous immunoglobulin may be considered a viable alternative when standard treatment fails to produce satisfactory results. In select cases, biologic therapies, like rituximab, that target specific immune system components may also be explored ( 7 , 16 – 19 ). For patients with relapsing-refractory disease without organ or life-threatening manifestations, interleukin-5 receptor antagonist in combination with steroids is recommended ( 3 , 20 , 21 ). Which can help reduce the need for oral glucocorticoids and potentially delay the progression of the disease ( 22 – 24 ). Currently, there are few cases of pediatric EGPA, and there is a lack of long-term follow-up data on the treatment of these patients. During the hospitalization, the child we reported had a rapidly progressing condition and multiple organs affected. Therefore, methylprednisolone in combination with CTX was chosen as the treatment option.

Suying Liu et al. discovered that individuals with damage to the CNS are more prone to experiencing digestive tract involvement ( 12 ). The microbiota-gut-brain axis theory offers a potential explanation for this connection ( 25 ). Cyclophosphamide is more effective at crossing the blood-brain barrier than rituximab. Therefore, glucocorticoids combined with cyclophosphamide are often the preferred initial treatment for EGPA affecting the CNS ( 26 ). Suying Liu et al. observed that intrathecal injection therapy had a positive impact. Zhou Jiaxin reported on 73 EGPA patients, finding that 11% had CNS involvement ( 27 ). All patients received methylprednisolone pulse therapy, and cyclophosphamide was the preferred treatment option.

In clinical practice, the five-factor score (FFS), which was meticulously developed and refined by the French Vasculitis Study Group, is utilized to assess disease risk factors and predict prognosis ( 1 ). It includes: (1) involvement of the gastrointestinal tract (2) cardiac involvement (3) serum creatinine levels surpassing 150 μmol/L (4) age exceeding 65 years (5) absence of ear, nose, and throat involvement. Each factor is assigned a score of 1, and higher cumulative scores indicate a poorer prognosis. However it fails to provide clear guidance for other adverse outcomes in EGPA patients, such as disability due to peripheral nerve involvement ( 20 ).

The case we are reporting is an EGPA patient with CNS who exhibits PRES accompanied by cerebral artery stenosis. Both domestically and internationally, there have been no reports on this condition in children. This highlights the diverse nature of neurological symptoms in EGPA patients. If patients exhibit allergic diseases, including asthma, allergic rhinitis, urticaria, and have elevated eosinophil counts, they should be highly suspected of having EGPA. It is crucial to conduct cranial imaging and other tests to diagnose EGPA as soon as possible and establish a corresponding treatment plan to improve the prognosis for these children.

EGPA is a rare condition, even more so in children. The absence of distinctive clinical manifestations makes it prone to misdiagnosis and delayed diagnosis, leading to many patients not receiving early diagnosis and treatment. Therefore, it is crucial to have a thorough understanding of the clinical characteristics of EGPA, diagnose and treat the condition promptly and consistently before severe organ involvement occurs, and prevent irreversible organ damage to enhance patient prognosis and quality of life.

Data availability statement

The original contributions presented in the study are included in the article/supplementary material. Further inquiries can be directed to the corresponding author.

Ethics statement

The studies involving humans were approved by the Affiliated Hospital of Qingdao University. The studies were conducted in accordance with the local legislation and institutional requirements. Written informed consent for participation in this study was provided by the participants’ legal guardians/next of kin. Written informed consent was obtained from the individual(s), and minor(s)’ legal guardian/next of kin, for the publication of any potentially identifiable images or data included in this article.

Author contributions

NN: Conceptualization, Data curation, Formal Analysis, Writing – original draft. LL: Conceptualization, Data curation, Formal Analysis, Writing – original draft. CB: Data curation, Formal Analysis, Methodology, Writing – original draft. DW: Data curation, Supervision, Writing – original draft. SG: Data curation, Supervision, Writing – original draft. JL: Data curation, Writing – original draft. RZ: Formal Analysis, Investigation, Writing – original draft. YL: Data curation, Supervision, Writing – original draft. QZ: Data curation, Supervision, Writing – original draft. HC: Conceptualization, Investigation, Project administration, Writing – review & editing.

The author(s) declare that no financial support was received for the research, authorship, and/or publication of this article.

Acknowledgments

The authors thank their colleagues at the Affiliated Hospital of Qingdao University for editorial support and comments.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

1. Comarmond C, Pagnoux C, Khellaf M, Cordier J-F, Hamidou M, Viallard J-F, et al. Eosinophilic granulomatosis with polyangiitis (Churg-Strauss): clinical characteristics and long-term followup of the 383 patients enrolled in the French Vasculitis Study Group cohort. Arthritis Rheum . (2013) 65:270–81. doi: 10.1002/art.37721

PubMed Abstract | CrossRef Full Text | Google Scholar

2. Nishi R, Koike H, Ohyama K, Fukami Y, Ikeda S, Kawagashira Y, et al. Differential clinicopathologic features of EGPA-associated neuropathy with and without ANCA. Neurology . (2020) 94:e1726–37. doi: 10.1212/WNL.0000000000009309

3. Emmi G, Bettiol A, Gelain E, Bajema IM, Berti A, Burns S, et al. Evidence-Based Guideline for the diagnosis and management of eosinophilic granulomatosis with polyangiitis. Nat Rev Rheumatol . (2023) 19:378–93. doi: 10.1038/s41584-023-00958-w

4. Masi AT, Hunder GG, Lie JT, Michel BA, Bloch DA, Arend WP, et al. The American College of Rheumatology 1990 criteria for the classification of Churg-Strauss syndrome (allergic granulomatosis and angiitis). Arthritis Rheum . (1990) 33:1094–100. doi: 10.1002/art.1780330806

5. Louthrenoo W, Norasetthada A, Khunamornpong S, Sreshthaputra A, Sukitawut W. Childhood churg-strauss syndrome. J Rheumatol . (1999) 26:1387–93

PubMed Abstract | Google Scholar

6. Pagnoux C, Guilpain P, Guillevin L. Churg-strauss syndrome. Curr Opin Rheumatol . (2007) 19:25–32. doi: 10.1097/BOR.0b013e3280119854

7. Greco A, Rizzo MI, De Virgilio A, Gallo A, Fusconi M, Ruoppolo G, et al. Churg-strauss syndrome. Autoimmun Rev . (2015) 14:341–8. doi: 10.1016/j.autrev.2014.12.004

8. Gioffredi A, Maritati F, Oliva E, Buzio C. Eosinophilic granulomatosis with polyangiitis: an overview. Front Immunol . (2014) 5:549. doi: 10.3389/fimmu.2014.00549

9. Zwerina J, Eger G, Englbrecht M, Manger B, Schett G. Churg-Strauss syndrome in childhood: a systematic literature review and clinical comparison with adult patients. Semin Arthritis Rheum . (2009) 39:108–15. doi: 10.1016/j.semarthrit.2008.05.004

10. Titlić M, Kodzoman K, Loncar D. Neurologic manifestations of hypereosinophilic syndrome–review of the literature. Acta Clin Croat . (2012) 51:65–9

11. André R, Cottin V, Saraux J-L, Blaison G, Bienvenu B, Cathebras P, et al. Central nervous system involvement in eosinophilic granulomatosis with polyangiitis (Churg-Strauss): Report of 26 patients and review of the literature. Autoimmun Rev . (2017) 16:963–9. doi: 10.1016/j.autrev.2017.07.007

12. Liu S, Guo L, Fan X, Zhang Z, Zhou J, Tian X, et al. Clinical features of central nervous system involvement in patients with eosinophilic granulomatosis with polyangiitis: a retrospective cohort study in China. Orphanet J Rare Dis . (2021) 16:152. doi: 10.1186/s13023-021-01780-x

13. Camara-Lemarroy CR, Lara-Campos JG, Perez-Contreras E, Rodríguez-Gutiérrez R, Galarza-Delgado DA. Takayasu’s arteritis and posterior reversible encephalopathy syndrome: a case-based review. Clin Rheumatol . (2013) 32:409–15. doi: 10.1007/s10067-012-2151-9

14. Ohta T, Sakano T, Shiotsu M, Furue T, Ohtani H, Kinoshita Y, et al. Reversible posterior leukoencephalopathy in a patient with Wegener granulomatosis. Pediatr Nephrol . (2004) 19:442–4. doi: 10.1007/s00467-003-1286-y

15. Eleftheriou D, Gale H, Pilkington C, Fenton M, Sebire NJ, Brogan PA. Eosinophilic granulomatosis with polyangiitis in childhood: retrospective experience from a tertiary referral centre in the UK. Rheumatol (Oxford) . (2016) 55:1263–72. doi: 10.1093/rheumatology/kew029

CrossRef Full Text | Google Scholar

16. Hayashi H, Fukutomi Y, Mitsui C, Kajiwara K, Watai K, Kamide Y, et al. Omalizumab for aspirin hypersensitivity and leukotriene overproduction in aspirin-exacerbated respiratory disease. A randomized controlled trial. Am J Respir Crit Care Med . (2020) 201:1488–98. doi: 10.1164/rccm.201906-1215OC

17. Agache I, Akdis CA, Akdis M, Brockow K, Chivato T, Del Giacco S, et al. EAACI Biologicals Guidelines-Omalizumab for the treatment of chronic spontaneous urticaria in adults and in the paediatric population 12–17 years old. Allergy . (2022) 77:17–38. doi: 10.1111/all.15030

18. Navarro-Mendoza EP, Tobón GJ. Eosinophilic granulomatosis with polyangiitis: newer therapies. Curr Rheumatol Rep . (2018) 20:23. doi: 10.1007/s11926-018-0736-2

19. Plumb LA, Oni L, Marks SD, Tullus K. Paediatric anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis: an update on renal management. Pediatr Nephrol . (2018) 33:25–39. doi: 10.1007/s00467-016-3559-2

20. Cho HJ, Yune S, Seok JM, Cho EB, Min JH, Seo YL, et al. Clinical characteristics and treatment response of peripheral neuropathy in the presence of eosinophilic granulomatosis with polyangiitis (Churg-strauss syndrome): experience at a single tertiary center. J Clin Neurol . (2017) 13:77–83. doi: 10.3988/jcn.2017.13.1.77

21. Misra DP, Shenoy SN. Cardiac involvement in primary systemic vasculitis and potential drug therapies to reduce cardiovascular risk. Rheumatol Int . (2017) 37:151–67. doi: 10.1007/s00296-016-3435-1

22. Wechsler ME, Akuthota P, Jayne D, Khoury P, Klion A, Langford CA, et al. Mepolizumab or placebo for eosinophilic granulomatosis with polyangiitis. N Engl J Med . (2017) 376:1921–32. doi: 10.1056/NEJMoa1702079

23. Agache I, Song Y, Alonso-Coello P, Vogel Y, Rocha C, Solà I, et al. Efficacy and safety of treatment with biologicals for severe chronic rhinosinusitis with nasal polyps: A systematic review for the EAACI guidelines. Allergy . (2021) 76:2337–53. doi: 10.1111/all.14809

24. Guntur VP, Manka LA, Denson JL, Dunn RM, Dollin YT, Gill M, et al. Benralizumab as a steroid-sparing treatment option in eosinophilic granulomatosis with polyangiitis. J Allergy Clin Immunol Pract . (2021) 9:1186–1193.e1. doi: 10.1016/j.jaip.2020.09.054

25. Ma Y, Cui B, Chen ZH. Research progress on application of Marzumab in eosinophilia granulomatosis polyangiitis. J Fudan Univ (Medical Edition) . (2023) 50:134–9

Google Scholar

26. Anrather J, Iadecola C. Inflammation and stroke: an overview. Neurotherapeutics . (2016) 13:661–70. doi: 10.1007/s13311-016-0483-x

27. Zhou JX, Zhang SZ, Li J, Zhao LD, Wang Q, Fei YY. Central nervous system involvement in eosinophilic granulomatosis with polyangiitis: A retrospective study of 8 patients. Chin J Allergy Clin Immunol . (2017) 11:241–6

Keywords: eosinophilic granulomatosis with polyangiitis, child, central nervous system, diagnosis, therapy

Citation: Nie N, Liu L, Bai C, Wang D, Gao S, Liu J, Zhang R, Lin Y, Zhang Q and Chang H (2024) Eosinophilic granulomatous polyangiitis with central nervous system involvement in children: a case report and literature review. Front. Immunol. 15:1406424. doi: 10.3389/fimmu.2024.1406424

Received: 26 March 2024; Accepted: 01 May 2024; Published: 15 May 2024.

Reviewed by:

Copyright © 2024 Nie, Liu, Bai, Wang, Gao, Liu, Zhang, Lin, Zhang and Chang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Hong Chang, [email protected]

† These authors have contributed equally to this work and share first authorship

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.