A 44-year-old man is brought to the emergency department after he was found talking to himself in a park. When authorities asked him to leave, he became agitated and combative, saying he was "destined to lead" and has to "wait in the park for the sign." The patient admits to not sleeping for the past week. His thoughts jump from topic to topic, and he appears distractible, disorganized, and unable to care for himself. The patient is admitted to the hospital and prescribed daily haloperidol and valproate. Over the next week, he becomes significantly calmer. Although he continues to believe that he will "lead a spiritual revolution," he sleeps 6 hours a night and is better able to focus. Ten days after admission, nursing staff members find him lying in bed, confused, sweating, and stiff. Temperature is 39.2 C (102.6 F), blood pressure is 164/98 mm Hg, pulse is 122/min, and respirations are 28/min. As a precaution, all medications are stopped. If the patient's condition fails to improve with supportive measures, which of the following medications would be most appropriate to administer at this time?
Neuroleptic malignant syndrome | |
Causative |
|
Pathophysiology |
|
Signs/symptoms |
|
Treatment |
|
This patient has neuroleptic malignant syndrome (NMS), a rare but potentially lethal adverse reaction to antipsychotic medications (neuroleptics). Its cardinal features include severe hyperthermia, autonomic dysregulation, lead-pipe rigidity, and altered mental status.
Treatment of NMS includes the following:
Prompt discontinuation of the offending agent (the antipsychotic). Both first-generation (eg, haloperidol) and second-generation antipsychotics can cause NMS. It may occur at any time but usually develops within the first 2 weeks of treatment.
Supportive care (ie, aggressive cooling, intravenous fluids, and electrolyte repletion).
Benzodiazepines, which can improve agitation and decrease muscle contraction
Bromocriptine or amantadine, dopaminergic medications that can be considered in a patient whose condition does not respond to supportive care and withdrawal of medication.
Dantrolene, a direct-acting muscle relaxant with a rapid onset of action that can reduce heat production and muscle rigidity.
(Choice A) The anticholinergic medication benztropine can be used to treat antipsychotic-induced extrapyramidal symptoms (eg, dystonia). Although extrapyramidal symptoms can present as stiffness in a patient taking antipsychotics, they would not be expected to cause hyperthermia, hypertension, altered mental status, and tachycardia.
(Choice C) Cyproheptadine, a serotonin antagonist, is used to treat severe cases of serotonin syndrome (SS). Although this patient has symptoms that overlap with SS (eg, autonomic instability, altered mental status), his exposure to an antipsychotic rather than a serotonergic medication and his lead-pipe rigidity, as opposed to hyperreflexia, are consistent with NMS.
(Choice D) Physostigmine is a cholinesterase inhibitor used to reverse the toxic CNS effects caused by anticholinergic drugs. Patients with anticholinergic toxicity would have dry skin, not diaphoresis.
(Choice E) The beta blocker propranolol can be used to control hypertension and tachycardia associated with NMS, but it would not address the underlying cause of these symptoms.
(Choice F) Succinylcholine is a very short-acting, depolarizing muscle relaxant used to induce brief paralysis during anesthesia. It can cause malignant hyperthermia, a clinical syndrome similar to NMS known to occur immediately following exposure to halogenated inhalational anesthetic agents. Succinylcholine is not a treatment for NMS.
Educational objective:
Neuroleptic malignant syndrome is a rare but potentially life-threatening emergency associated with the use of antipsychotics (neuroleptics). A patient whose condition does not improve with cessation of the antipsychotic and intensive supportive care can be treated with benzodiazepines, dopamine agonists, and/or dantrolene.