Malignant Catatonia Versus Neuroleptic Malignant Syndrome.

The clinical presentations of neuroleptic malignant syndrome (NMS) and malignant catatonia (MC) are similar, posing a diagnostic challenge. Here, we present a 58-year-old Caucasian male who presented to the emergency department with an altered mental state, fever, tachycardia, and rigidity. Labs were remarkable for elevated creatine phosphokinase (CPK) and leukocytosis. The patient was on a regimen of clozapine and cariprazine to manage schizophrenia, lorazepam to treat catatonia, and mirtazapine to treat insomnia and appetite stimulation. The patient was initially diagnosed with NMS after common metabolic, infectious, and substance-induced etiologies were ruled out. Within 72 hours of receiving dantrolene and lorazepam, the patient's fever, tachycardia, and other laboratory abnormalities resolved. However, when the patient's rigidity, waxy flexibility, mutism, and stupor persisted, the diagnosis was reconsidered and changed to MC. Our case discusses the overlapping clinical presentations of NMS and MC, demonstrating a diagnostic challenge.