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(Medicine 2000;79:201; N Engl J Med 2005;352:1112)
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- Central & peripheral serotonin (5-HT) receptors responsible for SS → excess stimulation caused by excess serotonin precursors or agonists, ↑ serotonin release, ↓ serotonin reuptake, ↓ serotonin metabolism
- Pharmacologic treatment → control signs/symptoms & ↓ 5-HT receptor activation if symptoms are severe
- ∼60% of SS cases occur ≤6h after change in dose or addition of medication (The ICU book. 3rd ed. 2007; N Engl J Med 2005;352:1112) 25% of cases present after 24h (Med Clin North Am 2005;89:1277); just as likely to develop with therapeutic doses as with overdoses (Crit Care Clin 1997;13:763)
- Left untreated → seizures, coma, rhabdomyolysis, metabolic acidosis, renal failure, cardiac failure, DIC; ↑ death in environments with ↑ ambient temp (Med Clin North Am 2005;89:1277)
- Most cases resolve within 24h after appropriate management (supportive care, stop serotonergic meds) (The ICU book. 3rd ed. 2007; N Engl J Med 2005;352:1112)
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Diagnosis & Evaluation
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(N Engl J Med 2005;352:1112; Med Clin North Am 2005;89:1277)
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- Neurologic changes: AMS, agitation, confusion, ataxia, akathisia; neuromuscular abnormalities (greater in lower extremities): tremor, muscle rigidity, hyperreflexia, clonus (most sensitive physical finding; most obvious in patellar deep tendon reflexes)
- Autonomic hyperactivity: diaphoresis, tachycardia, hypertension, tachypnea, ...