Case Report on Autoimmune Encephalitis Manifesting as Psychosis

Autoimmune encephalitis comprises a collection of diseases pathophysiologically differing in varying degrees, with etiology of autoantibodies against neuronal cell surface or synaptic antigens. Anti-NMDA receptor encephalitis is one among the family of autoimmune encephalitis, which is most frequent in children and young adults. The psychiatric symptoms usually seen are psychosis, aggression, compulsion, and fearfulness. Memory disturbances and psychiatric symptoms are not uncommon. The combination of psychotic symptoms with cognitive impairment should also be a concern for autoimmune encephalitis. Altering pattern of neuropsychiatric presentations makes it difficult to diagnose, thereby increasing the disease burden. The current case report is of a 43-year-old male who presented with isolated psychiatric symptoms to the psychiatric outpatient department. Due to the rapid onset of symptoms, neurology referral and magnetic resonance imaging brain were done, which showed no significant abnormality. With altered laboratory parameters and psychiatric symptoms, the patient was started with intravenous (IV) antibiotics, antivirals, antipsychotics, and other supportive care. Since there was no improvement in symptoms, cerebrospinal fluid analysis for encephalitis mosaic panel was done, which demonstrated antibodies against N-methyl-D-aspartate receptor. Active management with IV immunoglobulin and steroids showed pronounced improvement in the patient’s condition.