A 25-year-old man with a history of depression, currently taking sertraline, presents to the emergency department with altered mental status, agitation, hyperthermia (103°F/39.4°C), diaphoresis, and hyperreflexia. His pupils are dilated. His family reports he recently started taking a new over-the-counter cough medication containing dextromethorphan. What is the most likely diagnosis?
✓ Correct Answer: Option C
The combination of SSRI (sertraline) and dextromethorphan (a weak serotonin reuptake inhibitor and NMDA receptor antagonist) can precipitate serotonin syndrome. Key features include altered mental status, autonomic instability (hyperthermia, diaphoresis), and neuromuscular hyperactivity (hyperreflexia, clonus).