The purpose of a case report is to describe a unique or extremely unusual patient case that has educational value to other physicians. Most commonly, case reports are written for 1 of 4 reasons:
To report a previously undescribed disease or syndrome;
To report the unexpected association of 2 or more diseases, disorders, or symptoms, especially if a common cause is likely;
To report a new and clinically relevant variation in a disease or syndrome (for example, the occurrence in an adult of a disease previously seen only in children; disease in a human caused by a pathogen previously believed to cause disease only in animals); or
To report unexpected events encountered while treating a patient (for example, new beneficial or adverse effect of a drug).
Some journals also publish case reports on the use of radiologic imaging, pathologic analysis, or new technology to resolve diagnostic dilemmas and on new uses for existing therapies.
An essential step in deciding whether to write a case report is to perform a thorough literature search to determine whether the case is in fact unique or extremely unusual. Learn more about literature searching.
You should also review the author instructions as well as recent issues of journals in which you would like to publish to find out what kinds of case reports, if any, those journals publish. Some journals publish cases as letters to the editor; others use the Introduction, Case Description, and Discussion format described below.
For most case reports, especially those that will include protected health information (PHI), you must obtain permission from the patient or his or her legally authorized representative to publish that information. In fact, obtaining permission is recommended even if the case report will not contain PHI because anyone familiar with a particular patient’s case will likely recognize who is being discussed in the case report. Furthermore, many journals require that the consent of the patient or his or her family be obtained before the report can be published. Additional permission is required to publish recognizable photographs or other images of a patient. Placing a black bar over a patient’s eyes in a photograph is no longer considered adequate to disguise the patient’s identity; the patient’s or authorized representative’s consent will still be needed in such circumstances. For more information about PHI, please contact the Institutional Compliance Office at (713) 745-6636.
The patient should be referred to throughout the article as “the patient” or as “he” or “she” and never as “the case.” (It is fine to say, “We report the case of a patient with . . . .”) The patient’s medical record number, name, or initials should never be mentioned (and such identifiers should be deleted from radiologic images or other figures used to illustrate the case).
The Introduction section of your case report should briefly establish the rationale for reporting the case, including its importance. For example, you might establish that a condition is unique or rare while relating it to conditions that other physicians might see more often in practice. At the end of the Introduction, you should include 1 or more sentences on the purpose of the case report. These sentences should indicate why the case is being reported and how it contributes to medical knowledge (in other words, what readers will gain by reading about it).
The following example does these things well:
Although peripheral arthritis is the most common extraintestinal manifestation of inflammatory bowel disease, it is very rarely addressed in the orthopaedic literature. The overwhelming majority of patients with inflammatory bowel disease present with gastrointestinal symptoms and do not have any joint involvement until much later. We present the case of a patient who had joint pain and swelling but lacked any sign of gastrointestinal involvement. After 5 months of workup, the patient was diagnosed with Crohn disease, and the joint symptoms improved with appropriate medical treatment. We believe that inflammatory bowel disease should be considered in the differential diagnosis of joint pain and swelling. (From Olszewski MA et al. Knee pain and swelling due to Crohn disease. J Bone Joint Surg Am 87:1844–1847, 2005.)
This Introduction begins by talking about conditions that are commonly seen in medical practice, indicates that the case described was extremely unusual (why it is being reported), and encourages physicians to consider Crohn disease in patients who present with joint swelling (how the case contributes to medical knowledge).
Sometimes references are needed to explain why a case is being reported. If appropriate, you can cite review articles instead of individual cases or studies to minimize the number of references. (Many journals have strict limits on the number of references permitted in case reports.)
The next section is a description of the case being reported. This section is typically labeled “Case Report,” “Case History,” or “Case Description” (depending on journal style).
The Case Description section should tell a story. You should include all relevant data to enable readers to understand the case and understand how you reached the diagnoses and treatment decisions, but you should omit details not directly relevant to the decisions or outcomes.
The case is usually presented in chronological order. It is important to keep the time frame clear for readers, especially if the case starts with referral to our institution and then requires a jump back in time to events that happened earlier. If the patient was treated at multiple institutions, you should make clear what was done at our institution.
The best sequence in which to present the details of the case will of course depend on the particular case, but a common order for a case report is:
Presenting signs, symptoms, and complaints;
Relevant medical history and relevant family medical history;
Other personal history relevant to the case (for example, tobacco use in a patient with lung cancer);
Medications being used;
Relevant results of physical examinations, laboratory tests (include normal range for unusual tests), and radiologic imaging;
Considerations during the differential diagnosis, preliminary diagnosis if different from final diagnosis, and any tests and treatments prompted by the preliminary diagnosis;
Final diagnosis and how it was determined;
Follow-up to present.
If the case requires reporting many data, a table may be an efficient way to present those data.
Cases that focus on histopathologic findings, results of specialized laboratory studies, and/or genetic findings may need separate sections for those findings (such sections typically appear after the Case Description section or as subsections of the Case Description section) or even separate Methods and Results sections if the tests are unusual or uncommon.
The Discussion section interprets the case for readers, supports the validity of your diagnoses and interpretations, and states the implications of the case. If you claim that your case is the first such case reported, you should also describe your literature search in this section (including what languages of publications you considered). [Note: It is always safest to add “to our knowledge” to any claim of being first.]
If other related cases have been reported, you should indicate in the Discussion how they are similar to and different from your case.
The Discussion is where you convince readers that your diagnosis or interpretations are correct and show that you considered other possibilities. If applicable, you should briefly discuss the differential diagnosis, including how you know your diagnosis is the correct one and why other possible diagnoses were rejected. You should always be sure to address any evidence that contradicts your diagnosis or interpretations.
The Discussion should also make clear your take-home message for readers. What should they consider doing differently as a result of reading this case (for example, when encountering a particular set of symptoms and test results in a particular patient setting, should they consider an additional diagnosis or a new treatment)? Or what shift in medical or scientific knowledge is suggested by this case, and what is the next step in advancing that knowledge?
Many journals require a brief abstract for each case report. The Abstract of a case report is usually unstructured (that is, contains no subheadings) and consists of 1 short paragraph. The Abstract should summarize the key points in the case, including the purpose (from the Introduction), unique features, final diagnosis, treatment, outcome (all from the Case Description), and take-home message of the case (from the Discussion). The Abstract should not include statements such as “X will be described” or “Y will be discussed”; these are not helpful to people reading your Abstract online.
Huth EJ. Writing and Publishing in Medicine, 3rd ed. (Philadelphia: Lippincot Williams & Wilkins, 1999).
Iles RL. Guidebook to Better Medical Writing. Olathe, KS, Island Press, 2004. Buckingham TA. Publication of case reports. Writing Medical and Scientific Papers 2(2):3–4, 2000 (electronic newsletter formerly available at http://www.lifescipub.com/vol2_no2.htm; accessed July 13, 2005).