Neuroleptic Malignant Syndrome

A catatonia-like state manifested by

• Extrapyramidal signs

• Blood pressure changes

• Altered consciousness

• Hyperpyrexia

Uncommon complication of antipsychotic treatment

Comorbid affective disorder as well as concomitant lithium use may increase risk

In most cases, occurs within 2 weeks of starting antipsychotic agent

Muscle rigidity, involuntary movements, confusion, dysarthria, dysphagia

Pallor, cardiovascular instability, pulmonary congestion, diaphoresis

Can result in stupor, coma, death

Differential diagnosis

• Malignant catatonia

• Malignant hyperthermia

• Neurotoxic syndromes (including AIDS)

• Various other conditions such as viral encephalitis, Wilson disease, central anticholinergic syndrome, and hypertonic states (eg, tetany, strychnine poisoning)

Elevated creatine kinase and leukocytosis with left shift in 50% of cases

Control of fever and intravenous fluid support

Bromocriptine, 2.5–10.0 mg three times daily orally, and amantadine, 100–200 mg twice daily orally, can be tried

Dantrolene, 50 mg intravenously as needed to maximum of 10 mg/kg/day, can alleviate rigidity

Efficacy of these three agents as well as the use of calcium channel blockers and benzodiazepines remains controversial

Electroconvulsive therapy has been used in resistant cases

Clozapine has been used safely in patients with a history of neuroleptic malignant syndrome