NCLEX Review Guide: Neuroleptic Malignant Syndrome

Definition & Mechanism

• Neuroleptic Malignant Syndrome (NMS) is a rare but potentially fatal reaction to antipsychotic medications characterized by severe muscle rigidity, hyperthermia, and autonomic dysfunction.
• Results from dopamine receptor blockade in the hypothalamus and basal ganglia, leading to disrupted thermoregulation and motor control.

Cardinal Signs - "FEVER"

• Hyperthermia often exceeds 104°F (40°C) and is associated with profuse diaphoresis and dehydration.
• Lead-pipe rigidity affects all muscle groups, making movement extremely difficult and contributing to hyperthermia.
• Autonomic instability includes tachycardia, labile blood pressure, tachypnea, and cardiac arrhythmias.
• Mental status changes range from confusion and agitation to stupor and coma.

High-Risk Medications

• Typical antipsychotics: Haloperidol, fluphenazine, chlorpromazine (higher risk than atypicals)
• Atypical antipsychotics: Risperidone, olanzapine, quetiapine, aripiprazole
• Antiemetics with dopamine-blocking properties: Metoclopramide, prochlorperazine

Laboratory Findings

• Creatine kinase (CK) markedly elevated (>1000 U/L), indicating muscle breakdown from rigidity.
• Elevated liver enzymes (AST, ALT, LDH) and myoglobinuria may indicate rhabdomyolysis.
• Leukocytosis with left shift, metabolic acidosis, and electrolyte imbalances common.

Emergency Interventions

1. Immediately discontinue the offending antipsychotic medication
2. Provide aggressive cooling measures (cooling blankets, ice packs, cool IV fluids)
3. Administer IV fluids for hydration and to prevent renal failure from myoglobinuria
4. Monitor vital signs continuously and cardiac rhythm
5. Prepare for potential intubation if respiratory compromise occurs

Pharmacological Treatment

• Dantrolene sodium (muscle relaxant): 1-3 mg/kg IV, reduces muscle rigidity and heat production.
• Bromocriptine (dopamine agonist): 2.5-10 mg PO/NG TID, helps restore dopamine activity.
• Supportive care with antipyretics (avoid aspirin due to bleeding risk) and benzodiazepines for agitation.

Priority Nursing Diagnoses

• Hyperthermia related to muscle rigidity and impaired thermoregulation
• Risk for injury related to altered mental status and muscle rigidity
• Fluid volume deficit related to diaphoresis and decreased oral intake