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Serotonin Syndrome — MRCPsych Paper B MCQ

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HardLiaison PsychiatrySerotonin SyndromeMRCPsych Paper B

A 38-year-old man presents with features of serotonin syndrome. He takes venlafaxine 375mg daily and recently started tramadol for back pain. Which combination of clinical features is most consistent with serotonin syndrome?

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Correct answer: A — Agitation, clonus, diaphoresis, and hyperthermia

Serotonin syndrome is characterised by the triad of neuromuscular excitation (clonus, hyperreflexia, myoclonus), autonomic dysfunction (diaphoresis, tachycardia, hyperthermia), and altered mental state (agitation, confusion). It differs from NMS which presents with lead-pipe rigidity and develops over days rather than hours. Tramadol has serotonergic properties and can precipitate serotonin syndrome when combined with SNRIs.

Reference: Maudsley Prescribing Guidelines 15th Edition 2024; BNF 2025