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REVIEW ARTICLE
Year : 2022 | Volume
: 17
| Issue : 6 | Page : 306-313
Writing case reports and series: Tricks, traps, and triumphs!
Abraham Edgar Gracia-Ramos
Departamento de Medicina Interna, UMAE Hospital General “Dr. Gaudencio González Garza”, Centro Médico Nacional “La Raza”, Instituto Mexicano del Seguro Social; Sección de Estudios de Posgrado e Investigación, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Mexico City, Mexico
Correspondence Address:
Dr. Abraham Edgar Gracia-Ramos
Departamento de Medicina Interna, UMAE Hospital General “Dr. Gaudencio González Garza”, Centro Médico Nacional “La Raza”, Instituto Mexicano del Seguro Social. Av. Jacaranda S/N, Col. La Raza, Alcaldía Azcapotzalco, C.P. 02990, Mexico City; Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional. Plan de San Luis y Díaz Mirón S/N, Col. Casco de Santo Tomás, Alcaldía Miguel Hidalgo, C.P. 11340, Mexico City
Mexico
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/0973-3698.364677
The case reports and case series are the oldest genres of medical literature. They constitute uncontrolled study designs with different varieties that describe important scientific observations that are missed or undetectable in other research methods. The advantages of employing case reporting include the discovery of unusual clinical conditions or unrecognized diseases, the detection of beneficial or side effects of treatments, the exploration of alternatives in clinical practice, solving ethical limitations, formulation of hypotheses, teaching, and the opportunity to generate publications. On the other hand, they have several shortcomings that limit their credibility such as the impossibility to generalize their findings, selection and recall bias, information preferences, overinterpretation (“anecdotal fallacy”), and the distraction of readers toward the unusual. The journey toward publishing a case study begins with the choice of the case, followed by an in-depth literature review on the issue. Obtaining the signed consent of the patients or their representatives and the selection of the journal for the publication of the article are the next steps. Writing a structured report may vary, but it can generally be represented by the acronym SIPDiSC: Summary (abstract), Introduction, Presentation, Discussion, Summary of the case experience, and Conclusion. Finally, a careful choice of authors should be made. Writing high-quality case reports and case series provides valuable information for clinical research, clinical practice, and medical education.
Keywords: Case reports, guideline, medical writing, publishing
The case report (also called clinical vignette or case study) is defined by Taber's Cyclopedic Medical Dictionary as “a formal summary of a unique patient and his or her illness, including the presenting signs and symptoms, diagnostic studies, treatment course, and outcome.”[2] The case report is the oldest genre of medical literature. The Eduard Smith papyrus (16th–17th dynasty, circa 1600 BC) is probably the most ancient example of medical literature that contains clinical cases.[3] Influential medical texts and renowned authors such as the Chinese Yellow Emperor's Classic, the Hippocratic Corpus, the Galenic case reports, Freud's case studies, and Osler's Principles and Practice of Medicine, all expound medical knowledge based on personal cases by the authors.[3],[4],[5] Until the second half of the 20th century, the case report genre held a leading place in the medical literature.[6] Thirty-eight percent of the published articles between 1946 and 1976 in three top journals (The Journal of the American Medical Association, The Lancet, and The New England Journal of Medicine) were case reports.[7] However, between 1971 and 1991, they were sidelined by other research articles which carried more scientific credibility because of the movement toward evidence-based medicine, and due to the fact that case reports were less quoted.[6] An analysis of the number of quotes according to the study designs in a sample of 2646 articles published from 1991 to 2001, found that case reports received negligible citations.[8] Thus, they can lower a journal's impact factor, potentially making the journal less attractive. From the late 1990s, a new interest in this genre emerged and, in 2007, the first medical journal focusing on case reports was launched.[9] In 2016, the account of journals focused on clinical cases amounted to more than 160 and this number is increasing. Most are open access, and others are “supplements” or “companions” to established medical journals. Besides, the Case Database, a registry for case reports, was established in 2012.[10] This review article shows the particular advantages and disadvantages of employing this study design and presents a framework to write high-quality case reports and case series.
What is the Role of Case Reports in the Evidence-Based Healthcare Era?The clinical evidence is hierarchically ranked according to the probability of bias. The higher up the hierarchy, the better its reliability and acceptance. Hence, randomized clinical trials (RCTs) and systematic reviews are placed at the top, while case reports are at the bottom.[11] Nevertheless, case reports describe important scientific observations that are missed or undetected in other research designs and provide insightful information in a way that might not be available otherwise.[12] There are many examples of significant advances in knowledge derived from case studies. In a selection of the 51 articles published by the Journal of the American Medical Association that “significantly changed the science and practice of medicine” five case reports were included.[13] The recognized benefits of case reporting are the following [Figure 1]:[14],[15],[16]
Figure 1: Advantages and disadvantages of employing case studies and case series. Created with BioRender.comDiscovery
Case studies can be the first step in the recognition of new diseases, atypical findings, an unusual course of illness, complications of interventions, and an association of diseases. Landmark examples include the report on Kaposi's sarcoma in young homosexual men that lead to the discovery of acquired immune deficiency syndrome, or the recognition of a case with “shaking palsy” that represents the first report of Parkinson's disease.[17],[18]
Detection of beneficial or side effects of treatments
The information provided from case reports or case series might be a valuable source for the treatment of uncommon diseases for which more rigorous methodologies are not available. The European Commission agrees with this approach to improve health care for rare disorders.[19] One recent example is the case series that reported a significant improvement in patients with Escherichia coli-associated hemolytic-uremic syndrome after treatment with eculizumab.[20] The above led to the rapid adoption of this drug as a treatment option. In another vein, case studies are often the first evidence in the detection of drug side effects that occur in less than one out of one thousand patients. The classic example is the recognition of the teratogenicity of thalidomide in humans.[21]
Exploration of alternatives in clinical practice
Medical practice is very heterogeneous throughout the world, largely because the availability of resources is not the same, especially in developing countries. Case reporting can lead to finding treatment alternatives or procedures that are performed as an option to standard care in low-income and/or emergency contexts.
Solving ethical limitations
Since case reporting is all about “natural experiments,” they can be the only available alternative for leading medical practice in situations where ethical limits prohibit experimental research.[15]
Formulation of hypotheses
Case reports may generate clues to new hypotheses that explain the pathophysiology of diseases or clues for the development of new treatments.[22] The principle that observations can lead to scientific discoveries is based on deductive scientific reasoning promoted by Karl Popper.[14] These hypotheses can be tested with other research methods to refuse or confirm them. In this regard, almost 25% of 103 case studies published in The Lancet were followed by the registration or publication of RCTs after a period of 5 years.[23]
Medical education
Typical clinical vignettes are a wonderful way of case-based teaching. A study by Bonney showed that the case studies teaching method, compared to classroom discussions and textbook reading, is more effective to improve the learning of several skills.[24] Moreover, some authors consider that the main objective of publishing case reports is teaching, and many case reports are written because of their educational value.[4],[25],[26] A study found that 89% of 139 case reports published in a Danish general medical journal had an educational role.[27]
Publication
Case reports represent an excellent opportunity for publication for novice researchers at the beginning of their scientific careers. Through writing case reports, junior authors can obtain educational benefits that include improving writing, critical thinking, hypotheses development, “collaborative writing” with mentors, gaining experience in the production of high-quality publications and the peer review process, as well as an increased understanding of patient-centered care.[4]
On the other hand, case reports and case series have several shortcomings in the credibility of their results[28][Figure 1]. The findings from case studies cannot be generalized because they do not come from representative population samples and the observed results do not imply a cause-effect relationship. Therefore, the observations could be a mere coincidence.[15] The selection bias is often introduced by publishing selected cases.[22] An analysis of 64 case reports and 39 case series published by The Lancet found reported negative outcomes in only 5% and 10%, respectively.[23] Other methodological limitations are recall bias (due to the lack of all the relevant data in the medical records) and information bias (because the sensitivity of the observer can interfere with the interpretation of what is observed). Finally, the overinterpretation or “anecdotal fallacy,” which is a tendency to generalize when there is no justification for it, and the distraction of readers when focusing on the unusual instead of the common problems are also limitations of the genre.[15]
Types of Case StudiesThe case studies can be considered as an exploratory research approach.[29] The “traditional” or “classic” case report is descriptive, observational, naturalistic (i.e., explore an event or phenomenon in depth and its natural context), and retrospective.[15] However, there are examples of case studies prospectively designed, such as the first report of a patient with sickle cell disease or the prospective case series to evaluate a structured diagnostic protocol for fever of unknown origin.[30],[31] Other modifications to the “traditional format” of the case report include: (i) The “evidence-based case report” or “case-based review,” which provides a systematic literature review about the case issue;[32] (ii) the “interactive case report”, in which participation of readers is encouraged;[33] and (iii) the “integrated narrative and evidence-based case report,” which joins the patient's and doctor's narratives with the best evidence for a better comprehension of the case.[34]
Case studies can be classified according to the number of the same. A case report describes one or two cases (frequently only one). The case series usually includes three to ten cases.[1] Nevertheless, the number of cases found in articles with the title “case report” or “case series” is highly variable. One study reported that the mean number of cases included in an article with the title “case series” was 7 (range 1-6432) while the mean number of reports included in those articles with the title “case report” was 4 (range 1-178).[35]
In accordance with their purpose, there are three main types of case studies: intrinsic, instrumental, and collective. An intrinsic case report shows a unique phenomenon, which distinguishes it from the others. In contrast, the instrumental case report uses as an example a particular case to describe an issue or phenomenon. The collective case study includes the analysis of multiple cases sequentially or simultaneously with the aim to yield a broader assessment of a particular issue.[36]
The Journey Toward Publishing a Case StudyThe steps to developing a case report are listed in [Figure 2].
Select the case(s)
The first step in the journey to publishing a report is the selection of the most appropriate case. The most common reasons that make a case suitable for its publication are summarized in [Table 1]. The source of the cases is the clinical practice and, as Powell said, “almost all practicing physicians eventually will encounter a case worthy of being reported”.[37] Therefore, always “keep an eye” on unusual findings during your practice in the clinical setting.[29] Remember, the potential case must be compelling, pithy, and focused on one topic.[38] In an intrinsic case study, the report is chosen based on its uniqueness, which is of genuine interest to the researchers. For an instrumental case study, a “typical” case that is instructive, educational, and allows the analysis of one issue or phenomenon must be selected. In collective or multiple case reports, the cases are carefully selected to try the replication theory of the findings. It is recommended to include two or three literal replications (i.e., predicting similar outcomes) if the theory is straightforward and five or more if the theory is more subtle.[36]
Literature review
Once a potential case is selected, the following step is a broad literature review of the condition. A careful literature search with proper search keywords across large databases (PubMed, MEDLINE, Ovid, Scopus, Embase, Web of Science, and Google Scholar) is always advisable.[39] The reasons for this research are several. A thorough literature search helps in identifying if the case is really unusual, and the uniqueness or rarity of the findings. In addition, reading published case studies on the same issue will help in the preparation of the paper through the acquisition of enough knowledge to prove the point.[40]
Consent
The signed consent of the patient or their representatives for the publication of any personal information is a requirement according to the World Medical Association Declaration of Helsinki, the International Committee of Medical Journal Editors (ICMJE), and the Committee on Publication Ethics.[41],[42],[43] In view of this, it is imperative to obtain consent before writing the case and a statement indicating such must be clearly described in the manuscript.[44] If the patient is a child, the parents or legal guardian must consent instead, and in the case of the patient being a teenager, both the patient and the parents must consent. If the patient is deceased or incapacitated, consent should be obtained from the next-of-kin, which must be stated clearly in the document. In case of failure to obtain patient consent (because the patient is deceased or next-of-kin are not available), the report should state that.[29] However, publication without consent is permitted only in exceptional circumstances, and many journals do not take any risks in this respect.[45]
Choose the journal
The last step before writing the report is to choose the journal. For this, it is crucial to identify the target audience, ensuring that the case is revealing and sensitive for them.[25] Once the choice for an audience has been made, look for the journal that is most appropriate to access this audience. Consider if the report is of interest to a specialty or generalist audience, or if the case study is more relevant to physicians in a specific country or geographic region.[41] Examples of multidisciplinary and specialty medical journals that publish only case reports are shown in [Table 2]. In case of doubt, it's advisable to consult with the journal's editorial if the case can be of interest to it.[40]
Write the report
The structure
Elements to write a case report are shown in [Figure 3]. The structured presentation of a case report can be represented by the acronym SIPDiSC: Summary (abstract), Introduction to the case, Presentation of the case, Discussion of the case experience (which includes a detailed analysis and explanation in the light of the literature review), Summary of the case experience, and Conclusion that may be drawn from such an experience.[46] However, the precise format varies from one journal to another. A review of 249 journals shows that there is a wide variation in the instructions given to authors to report a case. The recommended length varied from 500 to 2000 words (mean 1000 words).[47] Therefore, instructions to authors for the journal should be consulted so the manuscript can be prepared in the appropriate style.[48] Remember, the case report can be rejected because it does not conform to the required format, no matter how good the content is.[39] Furthermore, in order to write an accurate, complete, and transparent case report, it is advisable to consult the CAse REport (CARE) Statement and Checklist. The CARE checklist is endorsed by many journals and has been translated into nine languages.[49]
Figure 3: Elements to write a case report. Created with BioRender.com. MeSH: Medical Subject Headings. *Include this section in a case-based reviewTitle
The title is the first and most read part of the article. Hence, it should be descriptive, accurate, and succinct about the subject. It should describe the core message of the case and attract the reader's attention.[29],[50] The words “case study,” “case report,” or “case series” and the main phenomenon of interest (e.g., symptoms, diagnoses, tests, and interventions) should appear in the title.[49] In another vein, ostentatious words (i.e., words such as “unique case,” or “first report of”), wordplay, double meaning, cute wording, or abbreviations should be avoided.[29],[50]
Abstract
The abstract should summarize the main information about the case concisely to give an overall idea about its content.[50] The abstract's format may vary depending on the journal's style. However, a structured abstract for a case study usually includes three sections: the introduction, case presentation, and conclusion. Its length varies from 100 to 250 words.[49] Remember, the abstract is one of the most crucial components of the manuscript because it allows researchers, reviewers, and editors to judge the level of interest in case report.[12],[51]
Keywords
Keywords that represent the core of the report should be selected using MeSH (Medical Subject Headings) terms.[49] Its number varies from three to ten words. The proper selection of keywords is important because they aid the indexers and allow the retrieval of the article during a search.[29],[51] Adding the word “case report” to the keywords to identify the type of publication is advisable.[49]
Introduction
The introduction provides context to emphasize the novelty of the case and the need for its publication.[52] It should present background information citing only highly relevant literature about the issue that helps authors to validate their claims.[12] On the other hand, an extensive review of the literature is not desirable.[41] Its length should not be more than three paragraphs.[12] The introduction should end with 1–3 phrases stating that the case has identified a gap in knowledge and its relevance as such.[49]
Case presentation
This section should provide a clear description of the patient with sufficient detail and explanation for the readers to establish their own conclusions about the case's validity.[12],[50] It is advisable to present patient information in a narrative form and in chronological order.[12],[53] Write the case in past tense and use descriptive terms that create pictures in the minds of the readers.[54] Remember, this part should read like an interesting story, which your readers should enjoy.[39] Describe the relevant demographic information of the patient such as age, height, weight, sex, race, and profession or occupation.[12] The patient's history should include all pertinent backgrounds including relevant family history, occupational and social history, treatment information, and allergy.[29] The current medical condition must include sufficient but not unnecessary information.[41] The physical examination starts with the vital signs, followed by the type of physical examination; also, abnormalities should be reported.[12],[16] The diagnostic test that supports the case and rules out a differential diagnosis should be described. Pertinent positive or negative laboratory results must be provided. Other relevant tests such as image studies, electrocardiograms, and pictures of histopathology may be provided if they are of interest to the report. Diagnostic or therapeutic procedures, the time in which they were made, and a summary of the result should be included. If applicable, add a detailed description of therapeutic interventions (medication's name, dose, frequency, and duration).[12] Describe the follow-up of the patient, the response to treatment without any ambiguity, and the conclusion of the case in a clear form.[51] Do not forget to block out any identifying information of the patient.[12]
It is advisable to show the relevant events of the report in chronological order through a timeline. These core elements should be carefully selected from the patient's history, case presentation, diagnostic tests, therapeutic intervention, follow-up, and outcomes. The objective is to provide a succinct and readily summary to the readers. Tables or figures may be used to depict the timeline.[41],[49]
Regarding the series of cases, some aspects must be considered to prepare a high-quality report. Whenever possible, the design of a case series should be longitudinal and prospective, with a predefined protocol.[23] The inclusion and exclusion criteria of the case series should be explicit.[22],[23] All patients from a department or institution fulfilling the criteria and giving their consent should be included.[23] If eligible patients refuse to be part of the study or for other reasons do not receive the intervention, or if patients are lost in follow-up, it should be documented.[22],[23] The patients' diagnosis must be well documented and open to scrutiny. The patient outcomes need to be clearly defined and as objective as possible.[23]
Methods section
In a case-based review, a methods section should be included, in a similar way to that described for systematic reviews.[48] The literature search should provide enough details for the readers to easily reproduce it.[12] A well-structured question should be formulated, followed by a description of terms used in the search strategy (preferably MeSH headings).[48] The search strategy should include the criteria for selecting studies from the literature and should be able to run in multiple databases (Medline, Embase, Scopus, and Web of Sciences). To maximize retrieving the studies, authors should search the references of the revised articles.[12] The addition of a flow chart is advisable to clarify the selection of retrieved papers. Furthermore, a valid assessment of the studies' quality should be performed and included.[55] There are many checklists available to assist in the evaluation of case reports or case series, such as the Joanna Briggs Institute's tool for assessing case series,[56] the Pearson 5 component scheme,[29] the instruments proposed by Crowe et al.,[36] Murad et al.,[57] Garg et al.[52] and Ramulu et al.[58] A table listing pertinent information about the included studies from the literature review is a good option to show data in an interpretable form.
Discussion
It is considered the most important section because it explains the accuracy, validity, and uniqueness of the case.[12] The discussion should summarize and explain the main findings of the case and contrast them with what is already known in the literature, with an explanation to justify their similarities and differences. In order to compare the new case with the previous knowledge, the authors should provide a brief summary of the published literature.[12],[50] The discussion is not designed to provide an extensive literature review and cite all the references. Therefore, the articles cited should be critically evaluated and selected.[50] The limitations of the case should be listed together with an explanation of their significance. The contribution that the report adds to the current knowledge and the lessons that may be learned should be highlighted.[12] When appropriate, the patient's perspective should be added.[49] It is advisable to avoid the claim “the first report” because this is difficult to prove.[51] In the last paragraph, a conclusion of the case based on the literature reviewed should be provided by the authors along with justifiable evidence-based recommendations – the take-home message: that physicians may be aware of new diseases or findings, new ideas for research, the applicability of the discovery into the clinical practice.[12],[50] It avoids making recommendations and judgments based on speculations.[12]
References
The number and style of the references (generally 5 to 30 references) vary according to the journal's instructions. In addition to providing support to specific points of the case report, the included quotes provide a source for readers interested in learning more about the issue. Because of this, they should be carefully chosen.[50]
Choose the authors
Authorship of the manuscript must be considered carefully, based on a substantial contribution to the study. According to the ICMJE, the criteria that should be fulfilled to be considered an author include the contribution to conceptual development, data acquisition or analysis, involvement in the drafting of the manuscript, and the approval of the final version of the paper. Those individuals that do not fulfill these criteria should be included in the acknowledgment section. In another vein, it is mandatory that the included authors disclose any conflict of interest.[42] Authors should also refrain from excessive authorship without the proper credit because this is an unethical publication practice.
ConclusionCase reports and case series remain a valuable resource in the medical literature due to their importance to the development of new knowledge as well as for their substantial educational benefits. Due to this, the publication of high-quality reporting is particularly important.
Acknowledgments
The author is thankful to Professor Vinod Ravindran for his invitation to collaborate on this special supplement.
Financial support and sponsorship
Nil.
Conflicts of interest
The author is an Associate Editor at Oxford Medical Case Reports journal. The view offered by the author in this article does not necessarily represent the view of that journal.
References
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