Which of the following is a potential life-threatening reaction to antipsychotic medications?

• A. Serotonin syndrome
• B. Neuroleptic malignant syndrome
• C. Serotonin withdrawal
• D. NMS is not possible

Answer: (B)

Neuroleptic malignant syndrome is a rare but potentially life-threatening reaction to antipsychotic drugs caused by abrupt dopamine D2 receptor blockade in the CNS. It usually follows starting or increasing a high-potency antipsychotic and presents with a rapid onset of high fever, severe muscle rigidity (often described as lead-pipe rigidity), autonomic instability (including tachycardia and blood pressure fluctuations), and altered mental status. Lab findings often show markedly elevated creatine kinase from rhabdomyolysis, leukocytosis, and sometimes acute kidney injury.

Immediate management is crucial: stop the antipsychotic, provide aggressive supportive care (cooling, IV fluids, careful monitoring and correction of electrolytes), and consider specific treatments such as dantrolene or bromocriptine. Serotonin syndrome is a different toxicity linked to excess serotonergic activity and presents with hyperreflexia, clonus, agitation, and typically a quicker onset; it is not the classic reaction associated with antipsychotics, which is why the neuroleptic malignant syndrome choice best fits the scenario.