Finding the Cause of Psychosis: A Challenging Case of Anti-NMDAR Encephalitis.

An autoimmune response causing inflammation in the brain tissue is called autoimmune encephalitis. Autoantibodies directed against N-methyl-D-aspartate (NMDA) receptors cause a type of autoimmune encephalitis resulting in memory loss, confusion, and psychosis. A 28-year-old male with a history of schizophrenia, seizure disorder, and stroke presented with a 2-day history of bizarre behavior, restlessness, insomnia, agitation, and hallucinations. He was initially managed for acute psychosis without any improvement. Further workup for organic causes revealed positive NMDAR antibodies in both the cerebrospinal fluid and serum, confirming a diagnosis of autoimmune encephalitis. His condition later improved with steroids and intravenous immunoglobulins. This case signifies the importance of ruling out organic causes in patients with unexplained neuropsychiatric symptoms. NMDA encephalitis is more common in young females with underlying malignancies, especially ovarian teratomas. This case is unique, given the extremely rare occurrence of NMDA encephalitis in male patients without any malignancies.