Neuroleptic Malignant Syndrome

Neuroleptic Malignan Syndrome ( NMS )


Neuroleptic malignant syndrome is the rarest of the neuroleptic induced movement disorders. It is the most serious and represents a neurologic emergency in most cases. It has now been reported to occur with all drugs  that effect the central dopaminergic system (including dopamine agonists and levodopa). There's an isolated report of neuroleptic malignant syndrome in a patient on a trycyclic medication. It is likely an idiosyncratic reaction and  patients can, if needed, be given the same agent again without recurrence.

It is estimated that 0.5-1% of patients exposed to neuroleptics will develop  this syndrome. Most patients will develop it shortly after initial exposure and 90% within two weeks of starting the neuroleptic. It can occur with all the neuroleptics but haldol and trifluperazine are the most common. It has also  been seen with clozapine and metoclopramide.

The classic triad involves the autonomic nervous system (fever in 100%), the extrapyramidal system (rigidity), and cognitive changes. The two  characteristic laboratory findings reported in 75% of cases are a high CPK and leukocytosis. 95% of patients are iron deficient. The CSF is usually normal. The EEG can show diffuse slowing. Other features include tachypnea (78%),  diaphoresis (60%), and labile blood pressure (54%). The temperature does not usually exceed 41


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