Neuroleptic Malignant Syndrome

  • Neuroleptic Malignant Syndrome (NMS) is a potentially fatal reaction to antipsychotic medications that is characterized clinically by muscle rigidity, fever, autonomic instability, and altered level of consciousness.
  • Most accepted explanation for development of NMS is that of reduced
    dopaminergic activity secondary to neuroleptic-induced dopamine blockade.
  • It is found in various epidemiological studies that 0.02 to 3.2% of patients treated with antipsychotics to be affected with NMS.
Risk factors include:
  • Preexisting medical problems assciated with agitation or dehydration.
  • Neurological conditions
  • Human immunodefi ciency virus (HIV) infection
  • Rapid neuroleptization
  • High doses of antipsychotics
  • Coadministration of lithium with an antipsychotic
  • Male gender than female
  • Younger age
  • A previous diagnosis of a mood disorder
Clinical fetaures include:
  • Severe muscle rigidity
  • Hypepyrexia
  • Labile vital signs (tachycardia, unstable or elevated blood pressure)
  • Laboratory evidence of muscle injury (elevation of creatine kinase)
  • Leukocytosis.
  • Diaphoresis
  • Dysphagia
  • Tremor
  • Incontinence
  • Mutism
Differential diagnosis
  • CNS infection
  • Status epilepticus
  • Subcortical brain lesions
  • Porphyria
  • Tetanus
  • Lethal catatonia
  • Heat stroke

  • Warm, humid climates
  • Discontinue the antipsychotic
  • Supportive care in medical ICU
  • Monitor vital signs
  • Cooling blankets for fever
  • Administer antipyretics
  • Cardiac monitoring for arrhythmias
  • Parenteral hydration for dehydration
  • Monitoring for urine output and renal function
  • Hemodialysis in acute renal failure associated with myoglobinuria
  • Bromocriptine- dopamine agonist (5 to 10 mg orally three times a day)
  • Dantrolene- muscle relaxant
  • Administer intravenous dantrolene 1–3 mg/kg body weight/day, divided q.i.d.
  • Treatment of NMS should be individualized for each patient based on clinical signs and symptoms.
  • Electroconvulsive therapy (ECT) is another treatment option in NMS
  1. Miyamoto S, Merrill DB, Lieberman JA, Fleischacker WW, Marder SR. Antipsychotic Drugs. In Psychiatry, Third Edition. Edrs. Allan Tasman, Jerald Kay, Jeffrey A. Lieberman, Michael B. First and Mario Maj.John Wiley & Sons, Ltd, 2008.
  2. Daniel DG, Igan MF, Wolf SS. Neuropsychiatric Aspects of Movement Disorders. In Comprehensive Textbook of Psychiatry , Vol 7 , Kaplan HI and Saddock BJ (eds). Williams & Wilkins , Baltimore, MD, USA .


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