A 67-year-old man with a first episode of major depression is started on citalopram. Two weeks later he presents to the emergency department with confusion, agitation, diaphoresis, tremor, and fever of 38.8°C. His family reveals he was recently prescribed tramadol for back pain by his general practitioner. What is the most likely diagnosis?
- A Serotonin syndrome ✓
- B Neuroleptic malignant syndrome
- C Anticholinergic toxidrome
- D Lithium toxicity
Correct answer: A. Serotonin syndrome
Explanation
Serotonin syndrome results from excess serotonergic activity and classically presents with the triad of mental status changes, autonomic instability, and neuromuscular abnormalities (tremor, clonus, hyperreflexia). Tramadol inhibits serotonin reuptake and, when combined with an SSRI like citalopram, can precipitate this potentially life-threatening interaction. Neuroleptic malignant syndrome is associated with dopamine antagonist use and tends to develop more slowly with lead-pipe rigidity rather than tremor.
Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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