A 27-year-old man is brought to the emergency department after becoming agitated in a grocery store and screaming that voices are tormenting him and telling him to kill himself. The patient has a history of bipolar disorder currently treated with lithium and fluoxetine. In the emergency department, he becomes combative when approached by staff and receives several doses of intramuscular haloperidol and lorazepam. Urine toxicology is negative. The patient is admitted to the inpatient psychiatry unit, where he is placed in seclusion and restraints due to continued agitation. The following day he is calm but appears confused. He is disoriented to time and place and unable to respond to questions.
Temperature is 39.9 C (103.8 F), blood pressure is 180/90 mm Hg, pulse is 112/min, and respirations are 16/min. On examination, the patient is diaphoretic. He has tremors and severe, generalized muscle stiffness but no hyperreflexia or myoclonus. His examination is otherwise normal. Laboratory tests have been ordered but are still pending.
Which of the following is the most likely diagnosis in this patient?

Question

A 27-year-old man is brought to the emergency department after becoming agitated in a grocery store and screaming that voices are tormenting him and telling him to kill himself.  The patient has a history of bipolar disorder currently treated with lithium and fluoxetine.  In the emergency department, he becomes combative when approached by staff and receives several doses of intramuscular haloperidol and lorazepam.  Urine toxicology is negative.  The patient is admitted to the inpatient psychiatry unit, where he is placed in seclusion and restraints due to continued agitation.  The following day he is calm but appears confused.  He is disoriented to time and place and unable to respond to questions.
Temperature is 39.9 C (103.8 F), blood pressure is 180/90 mm Hg, pulse is 112/min, and respirations are 16/min.  On examination, the patient is diaphoretic.  He has tremors and severe, generalized muscle stiffness but no hyperreflexia or myoclonus.  His examination is otherwise normal.  Laboratory tests have been ordered but are still pending.
Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec193a_9696_90b8_853d_45923089fb7e_MD0002_00 The patient's acute onset of confusion, high fever, muscle rigidity, and diaphoresis after receiving multiple doses of intramuscular haloperidol is suggestive of neuroleptic malignant syndrome (NMS). NMS is an idiosyncratic drug reaction to dopamine antagonist medications that typically begins within days of drug initiation or dose escalation. It is characterized by a tetrad of mental status change, lead-pipe rigidity, fever, and autonomic dysregulation. Although most often seen with high-potency first-generation antipsychotics (eg, haloperidol), the syndrome can occur with second-generation antipsychotics. Key laboratory findings in NMS include elevated creatine kinase due to muscle necrosis and leukocytosis. In severe cases, myoglobinuria and acute renal failure can result. Treatment involves cessation of the offending agent and aggressive supportive measures. (Choice A) Drug-induced parkinsonism is a type of extrapyramidal symptom characterized by tremor, rigidity, bradykinesia, and gait abnormalities. It would not explain this patient's high fever and autonomic instability. (Choice B) Lithium intoxication presents with coarse tremors, ataxia, altered mental status, and gastrointestinal symptoms. It would not cause generalized muscle rigidity and hyperthermia as seen in this patient and can be ruled out by obtaining a lithium level. (Choice C) Malignant hyperthermia is a rare genetic disorder that presents with muscle rigidity and hyperthermia in the setting of exposure to volatile anesthetics or succinylcholine. (Choice E) Serotonin syndrome (typically caused by multiple serotonergic drugs or drug interactions) can be difficult to distinguish from NMS as both can present with fever, mental status change, and autonomic instability. Serotonin syndrome is characterized by neuromuscular irritability rather than the lead-pipe rigidity seen in NMS. Hyperreflexia and myoclonus are typical in serotonin syndrome and are not found in this patient. In addition, fever in serotonin syndrome is usually not as high as it is in NMS, and gastrointestinal symptoms (nausea, vomiting, and diarrhea) are more common. Educational objective: Neuroleptic malignant syndrome is a life-threatening, idiosyncratic drug reaction to dopamine antagonists. It typically occurs within days of antipsychotic initiation or dose escalation and presents with high fever, generalized muscle rigidity, autonomic instability, and mental status change. __________ References: Neuroleptic malignant syndrome: an easily overlooked neurologic emergency. (http://www.ncbi.nlm.nih.gov/pubmed/28144147) Neuroleptic malignant syndrome: a review for neurohospitalists. (http://www.ncbi.nlm.nih.gov/pubmed/23983836)

A 27-Year-Old Man Is Brought to the Emergency Department After