Unmasking Malignant Catatonia: A Diagnostic Challenge in a Febrile Patient With Altered Mental Status.

Malignant catatonia is a rare but life-threatening neuropsychiatric emergency characterized by catatonic features, autonomic instability, and fever. Prompt recognition is essential to avoid serious complications. We report a case of a 49-year-old Filipino male with schizoaffective disorder who presented with altered mental status and persistent fever. Initial investigations revealed severe hyponatremia, which was corrected, yet the patient remained encephalopathic. Despite an extensive workup, no infectious or structural cause was identified. He exhibited classic catatonic signs, including mutism, stupor, and echophenomena. A Bush-Francis Catatonia Rating Scale helps to support the diagnosis of malignant catatonia. Treatment with lorazepam led to rapid clinical improvement and resolution of fever. This case underscores the diagnostic complexity of malignant catatonia, particularly when presenting with fever and altered consciousness. Differentiation from neuroleptic malignant syndrome and encephalitis is critical due to differing management strategies.