Neuroleptic Malignant Syndrome (NMS)

Homepage: EMNote.org ■ 🚩Membership: https://tinyurl.com/joinemnote 🚩ACLS Lecture: https://tinyurl.com/emnoteacls Neuroleptic Malignant Syndrome Neuroleptic Malignant Syndrome Neuroleptic Malignant Syndrome (NMS) is a rare but life-threatening reaction to dopamine-blocking agents Key features: Hyperthermia, muscle rigidity, altered mental status, autonomic dysfunction Incidence: 0.1% to 3.2% in patients on neuroleptics Early recognition and treatment are essential to reduce morbidity and mortality Case Presentation 45-year-old female with schizophrenia treated with haloperidol and lorazepam Developed fever, rigidity, altered consciousness, autonomic instability Laboratory findings: Leukocytosis (14,000/mm³) Elevated CPK (5919 IU/L) – sign of muscle breakdown Acute kidney injury (Creatinine 1.6 mg/dL) Diagnosis: Neuroleptic Malignant Syndrome Management and Outcome Immediate discontinuation of neuroleptics Supportive care: Fluids, cooling, oxygen therapy Pharmacologic treatment: Bromocriptine (dopamine agonist) Benzodiazepines (for agitation and muscle rigidity) Recovery: Neurological improvement by Day 5, discharged from ICU on Day 9 Pathophysiology & Risk Factors Cause: Dopamine blockade → impaired thermoregulation, muscle rigidity, and autonomic dysfunction High-risk medications: Typical antipsychotics (haloperidol, fluphenazine) Atypical antipsychotics (olanzapine, risperidone) Other dopamine antagonists (metoclopramide, TCAs) Risk factors: High-dose or rapid escalation of antipsychotics Parenteral administration Dehydration Underlying psychiatric illness Clinical Presentation Onset: Within 24 hours to 1 week of exposure Cardinal Symptoms: Hyperthermia (above 38°C) Lead-pipe rigidity Altered mental status Autonomic instability (tachycardia, diaphoresis) Lab findings: Elevated CPK (above 1000 IU/L) → Rhabdomyolysis Leukocytosis, AKI Differential Diagnosis Serotonin Syndrome – Hyperreflexia, clonus, mydriasis Malignant Hyperthermia – Post-anesthetic exposure Malignant Catatonia – Psychiatric disorder-related Toxic/Metabolic Encephalopathy CNS infections Treatment Approaches 1. Stop offending agent immediately 2. Supportive care IV hydration, electrolyte correction Cooling measures Oxygen therapy 3. Pharmacologic therapy (if severe): Dopamine agonists (Bromocriptine 2.5 mg TID, max 45 mg/day) Muscle relaxants (Dantrolene 1-2.5 mg/kg IV, max 10 mg/kg/day) Benzodiazepines Prognosis and Prevention Mortality reduced from 40% to 10-20% with ICU management High recurrence risk if reintroducing neuroleptics Prevention: Use low-dose, gradual titration if restarting neuroleptics Avoid high-potency agents if possible Conclusion NMS is a medical emergency requiring rapid recognition and ICU management Dopaminergic blockade is the core mechanism Early discontinuation of neuroleptics & supportive care are crucial Emergency physicians must stay vigilant, especially with IM haloperidol