Q: Is it ethical to publish two different outcomes from the same case as two separate case reports?
The results from our case report lead to two outcomes in different fields. It looks difficult to combine those results in one case report, so I am going to report them separately in two different articles. If I submit two separate case reports to journal(s) based on the two different outcomes, would that be regarded as a duplicate submission? In the first place, is it acceptable to report those results separately?
Your concern regarding duplicate submission is indeed justified. In the case of an empirical study, submitting two different outcomes as separate articles to journals might be possible if the focus of the two studies is completely different. However, for a case report, things are different. All the conditions in the patient are likely to be interlinked and therefore, they must all be presented together. Typically, the entire case history, treatment protocols, and outcomes are all presented in one case report. Submitting two different case reports based on the same case would be unethical, unless the two stories are so widely different that they are equivalent to writing two different case reports.
Since you have mentioned that the outcomes in your case are related to completely different fields, there is a possibility that they would warrant two separate case reports, but this would mean treading on dangerous territory. You have to evaluate this in an extremely objective manner and perhaps take the opinion of senior colleagues before arriving at a decision. Historically, case reports using the same case have led to retraction if detected after publication. Therefore, please be extremely cautious and think things through carefully before making two submissions. In case you do decide to write two separate reports, please ensure that the journal editors are aware of the other report that is being simultaneously written on the same case.