Canadian Medical Association Journal 1996; 154: 43-45
Paper reprints of the full text may be obtained from: Dr. Patricia Huston, CMAJ, PO Box 8650, Ottawa ON K1G 0G8; fax 613 523-0937; cmaweb@hpb.hwc.ca
Abstract
Identifying a case to report
Components of the case report
Peer review
Conclusion
References
Table 1: Criteria used to evaluate case reports submitted to CMAJ
The goal of a case report is to make an original contribution to medical knowledge by presenting a phenomenon that is new or clinically instructive. Thus, it is difficult to plan to write a case report. However, when a unique experience presents itself an author has a straightforward format in which to describe it: a nonstructured summary, an introduction, a description of the case and a commentary or discussion.
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Identifying a case to report
Good cases to report are those that involve a new disease or give insight into the pathogenesis of a disease, a possible relation between two diseases that had previously gone unnoticed, a new complication of a treatment or a new and practical approach to the diagnosis or management of a disease.
There are a couple of exceptions to this general rule of "something new." Occasionally cases that are not unique may be appropriate if, for example, they illustrate a problem that is not yet widely recognized and may have important public health implications. Conversely, not all unique cases merit publication. For example, a complex case involving an unusual combination of diseases, albeit unique, may not reveal any useful clinical insights.
Authors may try to affirm the uniqueness of their case by noting that it is the first reported case of its kind in Canada. This assertion is compelling when it refers to an infectious disease that hitherto had been unknown in Canada. It is less compelling when it refers to a well-documented but uncommon drug reaction, as responses to a medication rarely change across geopolitical boundaries.
Other types of case reports that used to be found in medical journals are now rarely considered for publication. Among those types identified by Huth(3) are:
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Components of the case report
A literature search is implicit in this process: similar cases should be presented briefly to inform the reader of the state of knowledge on the topic. If a large body of literature exists, the author needs to question whether one more case report will add anything to it. In such a situation it may be more appropriate to do a critical review of the literature.(4)
The results of all relevant tests and diagnostic procedures should be described. Normal values need be given only for less common laboratory tests, but exact drug doses and schedules must be described. The clinical reasoning that guided the clinician in ruling out other possible diagnoses should also be explained.
Occasionally it is reasonable to describe two or three similar cases in one report. Usually the first case is described fully, and only the important differences in physical findings or laboratory results are noted for the remaining cases. A small table can provide a useful summary of findings when several cases are presented.
Case reports are sometimes accompanied by photographs of the patient. If there is any possibility that the patient could be identified, permission to publish such photographs must be sought from the patient, or, if the patient is incompetent, from the patient's family. It is wise to obtain permission to publish the case report even when photographs are not used.(5)
It is all too common for authors to note that physicians should "maintain a high index of suspicion" in order to identify a rare disease. Most readers will prefer that authors refrain from making this trite admonition. Authors can rest assured that by perusing the findings and implications of the case, readers will spontaneously gain a heightened awareness of the condition in question.
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Peer review
All case reports are sent to peer review to assess their appropriateness for publication. Reviewers are asked to respond to a series of questions to determine whether all the elements of a good case report are present. The criteria used in evaluating case reports are listed in Table 1.
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Conclusion
The role of case reports in medical journals has changed. They used to have a general role in teaching as case studies. The role of case reports is narrower now, but it is still an important one: an "early warning system" to alert clinicians to possible new conditions, associations or adverse reactions.