A 33-year-old man is hospitalized for depression with psychotic features. The patient had been on outpatient phenelzine therapy for major depressive disorder but stopped taking the medication 3 weeks ago because he did not feel that it was helping. Two days ago, he was brought to the emergency department due to worsening depressive symptoms and new auditory hallucinations. He was started on citalopram and risperidone and admitted to the inpatient psychiatric unit. He has not been receiving any other medications. This morning, he was found to have acute-onset confusion and high fever. Temperature is 39.4 C (102.9 F), blood pressure is 160/80 mm Hg, pulse is 118/min, and respirations are 16/min. On examination, the patient is disoriented and unable to attend to the interview. He has severe muscle stiffness but no hyperreflexia. The remainder of the examination is within normal limits. Laboratory tests are ordered, but results are not yet available. Which of the following is the most likely provisional diagnosis in this patient?

Question

A 33-year-old man is hospitalized for depression with psychotic features.  The patient had been on outpatient phenelzine therapy for major depressive disorder but stopped taking the medication 3 weeks ago because he did not feel that it was helping.  Two days ago, he was brought to the emergency department due to worsening depressive symptoms and new auditory hallucinations.  He was started on citalopram and risperidone and admitted to the inpatient psychiatric unit.  He has not been receiving any other medications.  This morning, he was found to have acute-onset confusion and high fever.  Temperature is 39.4 C (102.9 F), blood pressure is 160/80 mm Hg, pulse is 118/min, and respirations are 16/min.  On examination, the patient is disoriented and unable to attend to the interview.  He has severe muscle stiffness but no hyperreflexia.  The remainder of the examination is within normal limits.  Laboratory tests are ordered, but results are not yet available.  Which of the following is the most likely provisional diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d7d5_e9ad_bc81_bdd1aada11af_MD0003_00 This patient's development of confusion, fever, and severe rigidity in the setting of recent initiation of the antipsychotic risperidone is suggestive of neuroleptic malignant syndrome (NMS). NMS is characterized by autonomic instability (with notably high fevers), delirium, generalized rigidity (often severe), rhabdomyolysis (with increased serum creatine kinase), and leukocytosis. It is a potentially life-threatening medical condition that can occur any time after treatment with an antipsychotic. Although most often seen with high-potency first-generation antipsychotics (eg, haloperidol), the syndrome can occur with all antipsychotics. It can develop over 1-3 days, with delirium often being the first manifestation. NMS Serotonin syndrome (SS) can be difficult to distinguish from NMS. SS is characterized by neuromuscular hyperactivity (eg, tremor, hyperreflexia, myoclonus), rather than the severe, generalized rigidity seen in this patient (Choice E). SS is typically due to a combination of serotonergic medications or the interaction of serotonergic medications (eg, citalopram) and monoamine oxidase inhibitors (MAOIs) (eg, switching from an MAOI to an SSRI with less than the required 2-week washout period). This patient had an adequate washout period given that he stopped the MAOI phenelzine 3 weeks ago before starting citalopram. (Choice A) Although malignant catatonia may share some features of NMS, it has an insidious onset and usually presents with a prodrome of motor agitation. NMS is more likely given the rapid onset of symptoms following initiation of an antipsychotic. (Choice B) Malignant hyperthermia may occur in genetically susceptible patients, leading to hypercarbia, muscle rigidity, and hyperthermia in the setting of perioperative exposure to volatile anesthetics or succinylcholine. Onset of malignant hyperthermia is much more rapid than that of NMS. (Choice C) Abrupt discontinuation of any antidepressant may result in both medical and neurological symptoms. However, if present, symptoms occur in the first few days after discontinuation and often subside after 2-3 weeks. Educational objective: Neuroleptic malignant syndrome is a life-threatening condition associated with the use of antipsychotics. It is characterized by delirium, high fever, autonomic instability, severe rigidity, elevated creatine kinase, and leukocytosis. References: Neuroleptic malignant syndrome: a review from a clinically oriented perspective. (http://www.ncbi.nlm.nih.gov/pubmed/26411967)

A 33-Year-Old Man Is Hospitalized for Depression with Psychotic Features