Serotonin syndrome presents with which of the following symptom clusters?

• A. Agitation, hyperreflexia with clonus, fever, and diaphoresis
• B. Hyporeflexia, bradykinesia, hypotension
• C. Weight gain and edema
• D. Dry mucous membranes and constipation

Answer: (A)

Serotonin syndrome occurs when there is too much serotonin activity in the body, causing a mix of autonomic hyperactivity, neuromuscular excitement, and mental-status changes. The most telling neuromuscular sign is hyperreflexia with clonus, often accompanied by agitation, fever, and diaphoresis as part of an autonomic storm. That combination fits this option best because it captures both the autonomic symptoms (fever, diaphoresis) and the characteristic neuromuscular finding (hyperreflexia with clonus) along with agitation.

The other patterns don’t fit serotonin syndrome. Hyporeflexia with bradykinesia and hypotension points more toward neuroleptic malignant syndrome or other conditions with reduced reflexes and rigid features. Weight gain and edema are more chronic, not the acute autonomic surge seen with serotonin excess. Dry mucous membranes and constipation suggest anticholinergic toxicity, not excess serotonin. If this syndrome is suspected, stopping serotonergic agents and providing supportive care is essential, with antidotal therapy (like cyproheptadine) considered in certain cases.