13 Research methods, statistics, critical review and evidence-based practice13.2 Epidemiological studies
13.2.2.1 Case reports
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Written by Resident Doctor Committee · Published
New in the 2027 syllabus
The College added this topic for exams from January 2027.
What a case report is
A case report describes one person's presentation, investigation, treatment and course. It is usually written because something about the case is unusual or informative.
A case series describes several people who share a feature. Neither design gives you a suitable comparison group on its own.
Their main value is as a signal. A report can suggest an unexpected adverse effect or a new clinical pattern, which gives later research a question to test.
Appraising a case report
Feature | What to check |
|---|---|
Timeline | Exposure, symptoms, investigations and recovery are clearly dated |
Diagnosis | The findings are reported, along with reasonable alternative explanations |
Intervention | Dose, duration, other treatments given at the same time, and adherence are stated |
Follow-up | Benefits, harms and remaining uncertainty are described |
Selection | The authors say clearly why they chose this case |
Dechallenge means the person improves after the exposure stops. This supports a possible link, but the improvement may be natural recovery or the effect of another treatment.
Rechallenge means the problem comes back on re-exposure. This can strengthen suspicion, but re-exposing someone just to prove an adverse effect is not ethically justified.
Publication bias favours unusual or favourable outcomes, so published cases may not reflect typical experience.
Limits and consent
You cannot estimate incidence or compare risk without a defined population at risk and a suitable comparison group.
Cause stays uncertain, because spontaneous change, other treatments given at the same time and confounding are not controlled.
Get the person's consent to publication and protect details that could identify them, even when the report leaves out their name.