Copyright © 2008 Mosby, An Imprint of Elsevier
NEUROLEPTIC MALIGNANT SYNDROME
Neuroleptic malignant syndrome (NMS) is a rare, potentially lethal complication of neuroleptic treatment characterized by hyperthermia, rigidity, confusion, diaphoresis, autonomic instability, elevated creatinephosphokinase (CPK), and leukocytosis ( Table 42-8 ). The symptoms of NMS may evolve gradually over time, usually starting with mental status changes and culminating in fever and elevated CPK. NMS probably occurs in fewer than 1% of patients receiving conventional antipsychotic agents, although subsyndromal cases may be much more common.   Parallels have been drawn between NMS andmalignant hyperthermia (resulting from general anesthesia), largely on the basis of common clinical characteristics. Patients with a history of either NMS or malignant hyperthermia, however, appear to be at no increased risk for developing the other syndrome, and analysis of muscle biopsy specimens has not consistently demonstrated a physiological link between the two conditions. Lethalcatatonia is a spontaneously occurring syndrome that may be indistinguishable from NMS and has been described in the absence of neuroleptic treatment. In addition, antipsychotic agents may impair temperature regulation and so may produce low-grade fever in the absence of other symptoms of NMS. The clinician's immediate response to NMS should be to discontinue medication andhospitalize the patient to provide IV fluids and cooling. Whether bromocriptine or dantrolene facilitates recovery remains the subject of debate.   It is important that reinstitution of antipsychotic medication be delayed at least 2 weeks until after the episode of NMS has resolved. NMS has been associated with clozapine and other atypical antipsychotics, but the incidence isprobably substantially lower than with conventional agents. It has been suggested that a variant of NMS without rigidity may result from use of atypical antipsychotics, although if such a syndrome occurs, it is probably quite rare.
Table 42-8 -- Neuroleptic Malignant Syndrome
|Presentation (may gradually evolve, usually in the following order):|
|Confusion and fluctuating levels of consciousness|
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