Clinical Manifestations of the Serotonin Syndrome

Cognitive and behavioral features:
confusion/disorientation, agitation/irritability, coma/unresponsiveness, anxiety,
hallucinations (visual and auditory)
Autonomic features:
hyperthermia, diaphoresis, sinus tachycardia, hypertension, dilated pupils, nausea,
flushing
Neuromuscular:
myoclonus (legs especially), hyperreflexia, muscle rigidity, restlessness/hyperactivity,
tremor, ataxia, extensor plantar responses

Clinical Features of Neuroleptic Malignant Syndrome

Administration of neuroleptics (especially high-potency conventional agents)
Hyperthermia >38.0C
Muscle rigidity (may have cogwheel rigidity)
Tremor, myoclonus
Stupor, mutism, delirium
Autonomic instability – tachycardia, labile BP
Tachypnea, dyspnea
Sweating, sialorrhea, incontinent
Dysarthria, dysphagia
Raised CPK & WCC, metabolic acidosis, hypoxia, low serum iron, raised
catecholamines, theta or delta waves on EEG
Complications: rhabdomyolysis, ARF, aspiration pneumonia, pulmonary embolus,
cardiac arrest, DIC, limb contractures, ischemic brain injury
Exclude other central or systemic or toxic causes of hyperthermia