Neuroleptic malignant syndrome: risk factors, pathophysiology, and treatment.

Neuroleptic malignant syndrome (NMS) is associated with the administration of antipsychotic agents and other drugs such as l-dopa, antidepressants, and antihistaminic agents. Unexpected changes in mental status, new-onset catatonia, episodic tachycardia, tachypnea, hypertension, dysarthria, dysphagia, diaphoresis, sialorrhea, incontinence, low-grade temperature elevations, and rigidity should arouse suspicion. Several lines of evidence provide support for the involvement of dopamine. Most of the drugs implicated in NMS are D2 dopamine receptor antagonists. Central noradrenergic activity is also possibly related to the disorder, as sympathetic hyperactivity is associated with the active phase of NMS. Currently, the definitive role of GABA deficiency in NMS is yet to be established. Differential diagnosis should include malignant hyperthermia, lethal catatonia, lithium toxicity, serotonin syndrome, and heat stroke. A high degree of suspicion and the discontinuation of antipsychotic agents even if the diagnosis is not established are essential for the safety of the patient. Treatment of NMS should be individualized and be based empirically on the character, duration, and severity of the clinical signs and symptoms noted. The initial step in the treatment of NMS is the removal of the offending agent. Full-blown NMS is a serious condition and requires immediate supportive, nutritive, and electrolyte therapies. The administration of drugs that can improve NMS, such as IV dantrolene and/or oral bromocriptine, may also be taken into consideration, based on the severity and nature of the NMS.