Case histories are not research projects. It is therefore difficult to define who should write them.
Photo: Einar Nilsen
Case reports form the core of medical science and medical disciplines. The stories of the patients we learn from constitute the human factor in diagnoses – including in the medical literature. These reports have several functions, the most important of which is to describe the unknown, unexpected or unusual: a new disease, possible reactions or adverse effects of a treatment or intervention, or possible unknown manifestations of a disease (1) . In all cases, the intention is for the reader to learn something. And doctors are like everyone else in that we remember things better if the knowledge is presented anecdotally (2) .
A case report is also a scientific article, where the information presented must be as complete as possible, and where co-authorship can boost careers and enhance reputations. So, who should write such reports, and what factors should be taken into account?
The International Committee of Medical Journal Editors (ICMJE, formerly known as the Vancouver Group) recommends that all co-authors meet four criteria (3, 4) . The first criterion is related to the preparatory work (substantial contributions to the conception or design of the work; or the acquisition, analysis, or interpretation of data for the work), while the other three relate to contributing significant intellectual content to the manuscript, approving the final version and agreeing to be accountable for all aspects of the work (3) . Those who meet the first criterion should be invited to take part (but should decline if they cannot meet the remaining criteria) (4) . Thus, there are no formal limits to how many co-authors an article can have.
Dozens of healthcare professionals are often involved in assessing and treating a single patient
However, while a research project is planned and executed, and the outcome is uncertain, the idea to write a case report will often arise when the result is already known. The data will typically be collected retrospectively and be limited to the efforts to assess and treat the patient. Who meets the first authorship criterion depends on who forms the idea and takes the initiative (and has the energy and time) to write, and which parts of the medical history should be focussed on in order to give readers the greatest learning value. The other criteria, however, apply as normal: all co-authors must contribute significant intellectual content, approve the manuscript before submission, and know and understand the medical history well enough to defend all aspects of the work.
Can anyone write a case report if they have the time, desire, patient permission and access to medical records? The answer is 'no', according to Akanksha Agrawal et al. in an article in the European Journal of Case Reports in Internal Medicine from 2019 (5) . They were unable to find any mention of authorship in the CARE (CAse REport) guidelines from 2013 (6) , and formed a consensus group to study which criteria should be applied. The CARE guidelines focus on the ability of case reports to form the basis for more systematic analyses. A case history must not therefore be published more than once. This can easily happen if a patient undergoes a lengthy assessment with many parties involved, and where several of these consider writing a case report without coordinating with each other. Agrawal et al. therefore recommended that the person who makes the diagnosis should 'own' the case report. If that person is not interested in publishing, their peers can then go ahead and do so. They also recommended that the final author should always be an experienced clinician, that the number of authors should be limited to three to five (5) , and that other contributors should be mentioned in the acknowledgements.
The editor of the European Journal of Case Reports in Internal Medicine endorsed the recommendations (5) , but such strict criteria for authorship do not appear to be common for case reports. However, most major academic journals have restrictions on the number of co-authors in a case report (7-9) . Modern medicine is complex, and dozens of healthcare professionals are often involved in assessing and treating a single patient, but not all of these can be co-authors according to the rules in many journals.
In the Journal of the Norwegian Medical Association, we have not yet considered it necessary to limit the number of authors in case reports. We have three types of articles in which medical history is central (10) . In order to write a good article under Educational case report , the first author may need to invite authors from several disciplines if it is clear from the nature of the article that they could make a substantial contribution to the text and meet the other authorship criteria. In Images in Medicine , on the other hand, it is the pictures that are the focus; the text is short and the case history is therefore also limited, while articles under Short case report are somewhere between the other two types of articles. The number of authors that will be necessary – and sufficient – to write a good case report for the Journal will therefore vary.