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Serotonin syndrome — SCE Acute Medicine MCQ

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HardPsychiatrySerotonin syndromeSCE Acute Medicine

A 29-year-old woman taking sertraline is admitted after using MDMA at a party. She is agitated, sweating and febrile with diarrhoea. Examination shows inducible clonus, hyperreflexia and tremor. Creatine kinase is mildly raised. What is the most likely diagnosis?

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Correct answer: E — Serotonin syndrome

Serotonergic drug exposure with rapid onset agitation, autonomic instability, diarrhoea, hyperreflexia and clonus indicates serotonin syndrome. Neuroleptic malignant syndrome usually evolves more slowly with lead-pipe rigidity after dopamine antagonists. Anticholinergic poisoning causes dry skin and urinary retention rather than clonus and diarrhoea. The pearl is that clonus is a high-yield sign in serotonin toxicity.

Reference: TOXBASE; BNF serotonergic toxicity