A case report is a detailed description of a single patient, although some may describe a small number of patients. It typically documents an unusual condition, unexpected outcome, new treatment response, or other noteworthy clinical observation.
Case reports are most commonly used in medicine and healthcare, where they help researchers and clinicians share observations that may be rare, novel, or not yet well understood.
How do case reports work?
Researchers or clinicians describe the clinical course of a patient, including their history, diagnosis, treatment, and outcome, often alongside relevant test results or follow-up information.
A case report may involve:
Describing a rare or unusual condition
Documenting an unexpected response to a treatment
Reporting a previously unknown side effect or complication
Highlighting an unusual diagnostic or clinical presentation
Following the progression and outcome of a patient over time
For example, a clinician might report an unexpected adverse reaction to a medication, describe a rare presentation of a disease, or document an unusual response to a new treatment.
Strengths of case reports
Case reports can:
Identify rare or previously unrecognized conditions or outcomes
Highlight unusual treatment responses or side effects
Provide detailed clinical information about an individual case
Raise early signals about potential treatment benefits, harms, or safety concerns
Generate new hypotheses or research questions
Draw attention to observations that may warrant further study
Case reports can be especially useful for identifying new or uncommon phenomena before they have been studied in larger groups.
Limitations of case reports
Because a case report focuses on a single case or a very small number of cases, its findings cannot usually be generalized to a broader population.
Case reports also do not typically include a comparison group, making it difficult to determine whether a treatment or exposure caused the observed outcome.
They may also be more vulnerable to bias because cases are often selected for publication precisely because they are unusual or noteworthy.
The findings may be influenced by the unique characteristics of the case, so additional research is usually needed to determine whether similar results occur in other patients or settings.