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• 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.

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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.

Prevent plagiarism, run a free check.

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 .

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• Volume 11, Issue 1
• Clinical, endoscopic and therapeutic features of bleeding Dieulafoy’s lesions: case series and literature review
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• http://orcid.org/0009-0007-8086-2231 Basma Aabdi 1 ,
• Ghizlane Kharrasse 1 ,
• Abdelkrim Zazour 2 ,
• Hajar Koulali 2 ,
• Ouiam Elmqaddem 2 ,
• Ismaili Zahi 1
• 1 Gastroenterology , Mohammed VI University Hospital Oujda, Morocco , Oujda , Morocco
• 2 Digestive Disease Research Laboratory (LARMAD) , Mohammed I University, Faculty of Medicine and Pharmacy, Oujda, Morocco , Oujda , Morocco
• Correspondence to Dr Basma Aabdi; basma.aabdi{at}ump.ac.ma

Objective Dieulafoy’s lesions (DLs) are a rare but potentially life-threatening source of gastrointestinal (GI) haemorrhage. They are responsible for roughly 1%–6.5% of all cases of acute non-variceal GI bleeding.

Here, we describe retrospectively the clinical and endoscopic features, review the short-term and long-term outcomes of endoscopic management of bleeding DLs and we identify rate and risk factors, of recurrence and mortality in our endoscopic unit.

Design Data were collected from patients presenting with GI haemorrhagic secondary to DLs between January 2018 and August 2023. Patients’ medical records as well as endoscopic databases were retrospectively reviewed. Demographic data, risk factors, bleeding site, outcomes of endoscopy techniques, recurrence and mortality rate were taken into account.

Results Among 1170 cases of GI bleeding, we identified only seven cases involving DLs. Median age was 74 years, with a male-to-female ratio of 2.5. 75% of patients had significant comorbidities, mainly cardiovascular diseases. Only anticoagulant and antiplatelet agents were significantly associated with DLs. All patients were presented with GI bleeding as their initial symptom. The initial endoscopy led to a diagnosis in 85% of the cases. Initial haemostasis was obtained in all patients treated endoscopically. Nevertheless, the study revealed early recurrence in two out of three patients treated solely with epinephrine injection or argon plasma coagulation. In contrast, one of three patients who received combined therapy, experienced late recurrence (average follow-up of 1 year). Pathological diagnosis was necessary in one case. One patient (14%) died of haemorrhagic shock. Average length of hospital stay was 3 days.

Conclusion Although rare, DLs may be responsible for active, recurrent and unexplained GI bleeding. Thanks to the emergence of endoscopic therapies, the recurrence rate has decreased and the prognosis has highly improved. Therefore, the endoscopic approach remains the first choice to manage bleeding DLs.

• GASTROINTESTINAL BLEEDING
• ENDOSCOPIC PROCEDURES
• GASTROINTESTINAL HAEMORRHAGE

Data availability statement

No data are available.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:  http://creativecommons.org/licenses/by-nc/4.0/ .

https://doi.org/10.1136/bmjgast-2023-001299

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WHAT IS ALREADY KNOWN ON THIS TOPIC

Dieulafoy’s lesion (DL) is responsible for active, recurrent and unexplained non-variceal gastrointestinal bleeding.

DL is classically located in the stomach, particularly along the lesser curvature.

The gold standard treatment in endoscopic therapy with high haemostasis rate.

Selective arterial embolisation through angiography or wedge resection as the preferred surgical procedure are two management options for recurrent and uncontrolled DLs.

WHAT THIS STUDY ADDS

The majority of cases of bleeding DL are diagnosed by endoscopic techniques and, in some cases, endoscopy is non-diagnostic and no bleeding site could be identified.

Prognosis mainly depends on patient comorbidities.

Anticoagulants and antiplatelet agents emerge as significant risk factors in the occurrence of DL bleeding.

Endoscopic banding ligation or haemoclipping are the most effective and successful option of treatment of DL and epinephrine injection is a suboptimal treatment.

Combined therapy gave better results than monotherapy in terms of permanent haemostasis. However, re-bleeding can also be shown with combined therapy.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

When oesophagogastroduodenal endoscopy and colonoscopy are unremarkable in suspected haemorrhagic DL, gastroenterologists should proceed with alternative techniques (single or double balloon enteroscopies for distal small bowel/CT angiography or surgery) to identify the bleeding site.

Mechanical therapy and combined therapy should not rule out the risk of re-bleeding.

Recurrence risk factors should be sought if bleeding DL was suspected. But, their absence does not rule out the diagnosis of re-bleeding.

Introduction

Dieulafoy’s lesion (DL) can be defined as a rupture of an abnormally large submucosal artery protruding into the mucosa through a small defect in the gastrointestinal (GI) wall. It could be responsible for 2% of acute GI haemorrhages and 5.8% of non-variceal upper GI bleeding but also rare lower GI bleeding. 1 2 The stomach, along the lesser curvature, is the most common site of the majority of DLs. 3 4 Although rare, DLs could be an important cause of life-threatening GI bleeding especially in the elderly. In addition, the mortality rate has declined from 80% to 9% with the advent of endoscopic approaches.

During this study, we retrospectively outlined the epidemiological, clinical and endoscopic features of bleeding DL. The aim objective was to assess our institutional experience in the management of DLs and to juxtapose the resulting outcomes with existing data in the medical literature.

This section outlines the experimental design, the materials used and the specific methodology adopted in conducting this study. This study was carried out in the Hepato-Gastroenterology and Digestive Endoscopy Department, University Hospital Center, spanning from January 2018 to August 2023.

Endoscopic data were retrospectively reviewed from emergent oesophagogastroduodenal endoscopy (OGD) and colonoscopy procedures conducted on 1170 patients presenting with GI bleeding. Furthermore, data were collected from two distinct digestive endoscopy units, namely the emergency unit and the interventional endoscopy unit. Procedures were carried out either by certified endoscopists or by emerging endoscopists under the guidance of an experienced team.

The seven patients who were diagnosed with DLs received intravenous proton pump inhibitors before endoscopic treatment. Thirteen patients presenting GI bleeding of unknown cause were excluded from this study.

All endoscopic examinations were performed according to international guidelines using two types of standard video endoscopes: PENTAX MEDCIAL 27″ Radiance, SC-WU27-G1522, 90X0660 and FUJIFILM 26″ Radiance, G2 HB, SC-WU26-A1511, 90XO623.

The endoscopic criteria employed for diagnosing DLs included the following: active arterial oozing, a bleeding point lacking visible underlying ulceration, micropulsatile streaming through a minute mucosal defect and visualisation of an adherent clot with a point of attachment to a tiny mucosal defect or the surrounding normal mucosa.

Various endoscopic haemostasis techniques were available; however, the choice of treatment approach was left to the discretion of the endoscopist and depended on the availability of equipment. The therapeutic methods used consisted of epinephrine injection (1:10 000 dilution) into and around the DL, argon plasma coagulation (APC) and haemoclipping.

To assess the success of therapeutic endoscopy, particular attention was given to the absence of bleeding from the DLs until the endoscope was withdrawn. Furthermore, follow-up endoscopy was conducted within a 24-hour to 48-hour timeframe following the initial procedure to confirm healing at the previous bleeding site.

Re-bleeding was defined as the presence of haemorrhagic shock accompanied by signs of ongoing blood loss following the initial transfusion and stabilisation. In cases where early recurrence (within 72 hours) was suspected, patients underwent endoscopic relook and retreatment. Surgical intervention was considered only when bleeding persisted after the second endoscopy or when the bleeding source could not be identified. To assess the possibility of late recurrence bleeding, long-term follow-up (up to 1 year) was conducted for all patients who had undergone endoscopic treatment.

Various factors were taken into consideration, including demographic data (age, gender, bleeding site and comorbidities), risk factors for GI bleeding such as medication use (non-steroidal anti-inflammatory drugs (NSAIDs), anticoagulants and antiplatelet agents), mode of presentation, laboratory results, blood transfusion requirements before and after endoscopic management, endoscopic techniques and outcomes, as well as re-bleeding and mortality rates.

Descriptive statistics were used to summarise patients’ data using Windows-based Excel software, V.2013. Categorical and continuous data were reported as percentages and medians (with IQR).

Among the 1020 OGD and 150 colonoscopies performed for acute GI bleeding in our endoscopy department between January 2018 and August 2023, DLs were identified as the aetiological factor in approximately 0.6% of patients presenting with acute GI bleeding.

In the study group, seven patients were diagnosed with DLs. Among these cases, five were male (71%), while two were female (28%). The median age of the patients was 74 years, with the youngest being 50 years old and the oldest 90. All of the cases presented with significant cardiovascular risk factors. Notable comorbidities included high blood pressure in two patients, heart disease in four patients and type II diabetes in three patients. Furthermore, a combination of comorbidities was observed in two patients.

Among the seven patients, only three were not taking any medications at the time of presentation. Two patients were on direct oral anticoagulants, one due to valvular heart disease and the other for severe heart failure. A single patient was taking acenocoumarol for arrhythmia-related heart disease, and an antiplatelet agent was prescribed for the patient with aortic valvular stenosis.

Five patients presented with isolated melena, one patient experienced both haematemesis and melena, and one patient had haematemesis along with haemodynamic instability necessitating a blood transfusion. No cases of rectal bleeding were reported.

The mean haemoglobin level at presentation was 74 g/L. Blood transfusion requirements varied from 2 to 5 units of packed red blood cells (mean of 2.8 units per patient). All patients exhibited preserved biological haemostasis parameters.

Demographic and clinical data of these series are summarised in online supplemental table 1 .

Supplemental material

DLs were identified in the stomach in two patients, specifically within the fundus. In two other cases, these lesions were located in the second duodenal portion. Additionally, one case was found to be situated in the bulb.

Throughout the study period, there was only one reported case of colonic DL, which was located in the right colic angle. Another case of ileal DL was also reported.

Six cases of DLs were diagnosed only by standard video endoscopes. The mean of 2.5 endoscopy sessions (range 1–4) was required for diagnosing and management of the DLs.

Different endoscopic haemostasis techniques were used. Initial haemostasis was achieved for six patients.

Epinephrine injection (1:10 000 dilution) was performed in only one patient (16%), allowing initial haemostasis. The maximal injection volume was 10 mL. However, the patient had re-bleeding (within 24 hours). Permanent haemostasis was achieved by using both APC and haemoclipping during subsequent endoscopy.

In our analysis, only two patients (33% of the cases) were managed solely with APC, without subsequent administration of epinephrine.

In one of these cases, early re-bleeding occurred, necessitating a second-look endoscopy to regain haemorrhage control. Unfortunately, the patient succumbed to haemorrhagic shock prior to endoscopic intervention.

In the remaining three patients in our study, a combination of therapeutic modalities was employed. Specifically, two cases were treated with both epinephrine injection and haemoclipping, as shown in figure 1 , while the third case underwent haemoclipping followed by APC application. In these three instances, the initial interventions successfully achieved haemostasis. Nevertheless, one of these cases experienced delayed recurrent bleeding 1 year after the initial treatment.

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Illustrative pictures of patient with active bleeding from fundic DL and haemostatic success after endoscopic treatment. (A) Voluminous gastric blood clot with punctiform sheet bleeding on the lesser curvature. (B) Endoscopic management with both epinephrine injection and haemoclipping.

There were no post-endoscopy complications. Table 1 summarises the earlier findings.

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Endoscopic data before and after endoscopic therapies in patients with bleeding Dieulafoy’s lesions

In one case, upper endoscopy initially failed to detect any indications of haemorrhage. Subsequent colonoscopy, however, revealed the presence of blood in the ileum, although the precise origin of the bleeding remained unclear. CT angiography subsequently showed active contrast extravasation within the central section of the small bowel, devoid of any visible mass. Unfortunately, both arterial embolisation and enteroscopy were unfeasible in the emergency setting. Concurrently, the patient’s haemodynamic condition deteriorated rapidly leading to an emergent exploratory laparotomy which successfully localised the site of bleeding, a segmental resection of the small bowel was performed. Subsequent pathological analysis confirmed the presence of a DL in the proximal ileum ( figures 2 and 3 ).

Surgical specimen showing a blood clot in the ileum.

Pathology specimen showing Dieulafoy’s lesion in the ileum.

The average length of hospital stay was 3 days. During the 1-year follow-up period, a single patient exhibited delayed recurrent bleeding attributed to DL. One patient (14% of cases), was died from bleeding-related complications.

DL was initially reported by Gallard in 1884. Another French surgeon, Georges Dieulafoy, described this lesion in 1898 as ‘Exulceratio simplex’. 3 DLs account for approximately 1.5% of all cases of acute upper GI bleeding and 3.5% of cases of jejunoileal bleeding. 5 In our study, 0.6% of patients presented with acute GI bleeding secondary to DLs (seven cases). Although it is rare, DL could be responsible for severe, active and recurrent haemorrhages. 6

Although old publications report a predilection towards advanced age, DLs can affect individuals of all age groups, with a median age in the sixth decade. We observed a distinct male predominance, with a sex ratio of two men to one woman. 3 6 Our patients fell within the same age range as reported in previous studies. However, we noted a significant male predominance, twice that which is mostly described in the literature. Moreover, the majority of affected patients are elderly with several comorbidities. In our series, as in other studies, 85% of patients were older than 65 years.

DL is anatomically defined as a vascular malformation characterised by an aberrant, tortuous, consistently large submucosal artery that causes bleeding in the absence of ulcers, aneurysms or erosions. In the literature we reviewed, a congenital anomaly has been suggested as a cause in younger individuals, whereas an acquired malformation has been proposed for elderly. 6

The presence of cardiovascular comorbidities, high blood pressure, chronic renal failure and diabetes are recognised as risk factors for the development of DLs. Several studies have suggested a correlation between bleeding DLs and chronic NSAID and anticoagulant use (in more than 40% of patients). Our findings are consistent with the role of anticoagulants and antiplatelet agents as risk factors in the occurrence of bleeding DLs. However, other authors have contested this causal association. No causal link has been established between alcohol or tobacco consumption and the occurrence of DLs. 6–9

DLs are primarily found in the stomach. Up to 80% of these lesions are located 6–10 cm from the gastro-oesophageal junction, along the lesser curvature of the stomach. Elsewhere, as reported in several studies, DLs can also occur in other locations, including the duodenum, the distal stomach and the oesophagus. 3 4 6 8 In our series, DLs were identified in both the stomach and the duodenum at similar rates (28% each).

Barbier et al 10 reported colonic DLs as an unusual cause of lower GI bleeding in 1985. Actually, this location is extremely rare, with fewer than 30 cases documented in the literature. Baxter and Aly 3 reported that colonic DLs accounted for 2% of their review of 45 case reports.

Ileal DLs represent an uncommon site for GI bleeding, comprising less than 1% of all DLs cases, 3 According to the literature review, approximately 10 cases of histologically proven ileal DLs have been reported. 11

Recent case reports have also described DLs occurrences in the cecum, appendix, jejunum and ano-rectum. 12–14 Nikolaidis et al 9 described that 43% of DLs cases were located at surgical anastomosis sites.

DLs are often asymptomatic. 15 The most common clinical presentation includes melena, followed by haematemesis or haematochezia. Haemoptysis or haemorrhagic shock has also been reported. The association of haematemesis and melena was found in almost 50% of patients. 6 In contrast, in our case series, 71% of patients presented with isolated melena, 14% presented only with haematemesis and 14% presented with both haematemesis and melena. Due to the severity and recurrence of GI bleeding, laboratory abnormalities were frequently observed. In our findings, 71% of our patients required transfusion of packed red blood cells, with a mean of 2.8 units.

According to the literature review, initial endoscopy has enabled a diagnosis in 65%–90% of cases. In the studies by Kasapidis et al 2 and Norton et al 16 an average of 1.9 or 1.3 endoscopic sessions were required for diagnosing DLs. In our study, DLs were diagnosed in 85% of patients during the initial endoscopy, with an average of 2.5 endoscopic sessions. The endoscopic criteria necessary for diagnosis included active arterial oozing, the presence of a bleeding point with no visible underlying ulceration, a protruding vessel, and visualisation of an adherent clot with attachment to a normal mucosal defect or through the surrounding normal mucosa. 6 8 In the current study, 28% of patients had an adherent clot, and approximately 71% of patients presented with active bleeding, either as spurting or oozing.

Indeed, in 33% of cases, establishing the diagnosis required more than one endoscopy. 8 In our study, approximately 20% of patients needed more than one endoscopy to confirm the diagnosis. Our findings were consistent with the literature.

Some unusual locations of bleeding DLs were challenging to diagnose. For instance, ileal DLs may be overlooked and inaccessible to conventional endoscopy. High volume bleeding may also be a factor that limits the sensitivity of endoscopy. Recently, single or double balloon enteroscopies identified DLs of the distal small bowel in 3.5% of patients. 5 Moreover, CT angiography may be useful to determine the site of bleeding. It can be shown as contrast extravasation from an eroded tortuous artery, 8 17 as in our case of ileal DL.

Pathological diagnosis, while may not be a routine practice, can become indispensable in diagnosis of DLs, especially in certain rare and challenging anatomical sites. Actually in our ileal case of DL, the diagnosis was exclusively established through histological examination.

Surgical wedge resection has been the standard treatment of DLs. Through emergent endoscopy, this option gradually replaced surgery and became first-line treatment for DLs. 18 However, no consensus is recommended for endoscopic management.

Actually, the majority of data collected on treatment approaches consist of small case series or limited retrospective reports. Three main endoscopic haemostatic techniques can be used 3 17 : thermal (heat probe coagulation or APC, regional injection (epinephrine or norepinephrine) and sclerotherapy, mechanical therapy (endoscopic band ligation (EBL) and haemoclipping).

Although the results of endoscopic haemostatic therapies were variable, the rate of permanent haemostasis was high, reaching 90%. In a retrospective study, APC was found to be very effective for management of bleeding DLs. 19 In our study, a re-bleeding was observed in one patient treated with APC, while permanent haemostasis was achieved in the other. Mechanical haemostasis provided by EBL or haemoclipping is the most effective option in the treatment of DLs with a high success rates (95%) and low risk of recurrence <10%. 20 21 Due to the risk of re-bleeding, epinephrine injection is considered as a suboptimal treatment and it is not recommended to be used alone. 8 These results are consistent with data achieved by this study. The use of combined therapy gave better results than monotherapy in terms of permanent haemostasis and low rate of re-bleeding. 8 22 By contrast, in this study, one patient treated by combined therapy including epinephrine and haemoclipping had a recurrent bleeding during the follow-up period.

Comparative results of endoscopic therapies from retrospective studies are summarised in table 2 .

Summary of findings from the literature on endoscopic therapy of patients with Dieulafoy’s lesions

Based on the current literature, the rate of re-bleeding is 9%–40% and increases with endoscopic monotherapy. 8 The overall risk of recurrence in the short-term (<72 hours) is around 10%. 23 In instances of recurrent and uncontrolled bleeding, two management options have been documented for DLs 6 8 : selective arterial embolisation through angiography or wedge resection as the preferred surgical procedure.

Thanks to emergent endoscopy, the mortality of DLs has significantly decreased from 80% to 8.6%. In the current study, one patient died from haemorrhagic shock (14%).

This study is subject to several inherent limitations. First, the relatively rare incidence of DLs has resulted in a limited sample size, which may compromise the ability to establish statistical significance for the findings. Furthermore, being a retrospective investigation, there is a potential for inaccuracies in the recorded medical histories and risk factors.

Notwithstanding these constraints, the study reveals a robust association between cardiovascular diseases and episodes of bleeding attributed to DLs. Additionally, the use of anticoagulants and antiplatelet agents emerges as significant risk factors in the development of DLs.

While uncommon, DL is unequivocally acknowledged as a potentially life-threatening source of acute GI haemorrhage, particularly among the elderly. Timely diagnosis and prompt endoscopic management, especially in elderly individuals with multiple risk factors, can be invaluable and lifesaving.

Haemoclipping and combined therapeutic modalities are emerging as the most efficacious approaches, demonstrating superior haemostasis rates when compared with injection therapy. Nevertheless, to establish the optimal endoscopic treatment for DLs, further comprehensive studies will be imperative in the future.

Ethics statements

Patient consent for publication.

Not applicable.

Ethics approval

This retrospective analysis was conducted according to the ethical principles of the Declaration of Helsinki and local legislation, informed consent was obtained from the seven participants for this retrospective study.

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Contributors BA: manuscript writing and analysis. GK: manuscript correction. AZ: verification of the overall reproducibility of the results. HK: evolution of the general aims and objectives of research. OE: methodology development. IZ: data visualisation and presentation. BA and IZ confirm and accept full responsibility for the overall content of the work as guarantors.

Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Competing interests None declared.

Provenance and peer review Not commissioned; externally peer reviewed.

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