Neuroleptic malignant syndrome (NMS) is a life- threatening neurological disorder most often caused by an adverse reaction to neuroleptic or antipsychotic drugs. It generally presents with muscle rigidity, fever, autonomic instability and cognitive changes such as delirium, and is associated with elevated creatine phosphokinase (CPK). Incidence of the disease has declined since its discovery (due to proactive prescription habits), but it is still dangerous to patients being treated with antipsychotics. Because of its unpredictability, there is no one set course of action to treat the syndrome, but generally, removal of the antipsychotic drug treatment, along with medical management, lead to a positive outcome.
Signs and symptoms
The first symptom to develop is usually muscular cramps, fever, symptoms of instability of the autonomic nervous system such as unstable blood pressure, and changes in cognition, including agitation, delirium and coma. Other symptoms may include muscle tremors. Once symptoms do appear, they rapidly progress and can reach peak intensity in as little as three days. These symptoms can last anywhere from eight hours to forty days. The muscular symptoms are most likely caused by the blockade of D2 which cause problems in the basal ganglia motor loop of the brain similar to that which exists in Parkinson's disease.
A raised white blood cell count and creatine phosphokinase (CPK) plasma concentration will be reported due to increased muscular activity and rhabdomyolysis (destruction of muscle tissue). The patient may suffer hypertensive crisis and metabolic acidosis. A non-generalized slowing on an EEG is reported in around 50% of cases.
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