Anti-NMDA Receptor Encephalitis Presented with Acute Psychotic Symptoms: A Case Report

Introduction: Anti-N-methyl-d-aspartic acid receptor (NMDAR) autoimmune encephalitis is one of the most challenging disorders with both psychiatric and neurologic presentations. Approximately three-fourth of patients with anti-NMDA receptor encephalitis (anti-NMDARE) first referred to psychiatrists. Case Presentation: A 15-year-old female adolescent was admitted to a psychiatric hospital. She presented a history of behavior changes, including aggression, the symptoms mimicking depression, and suicidal ideation, for one year. Then she showed more severe disinhibited behaviors, stupor, and generalized tonic-colonic seizure, so she was hospitalized in a general hospital. After neurological assessments, she was referred to a psychiatric hospital due to her uncontrollable aggressive behaviors in addition to sleep disturbance, rapid mood swings, restlessness, stereotypic behaviors, fluctuating attention and concentration, misidentification delusion, and perceptual changes. All lab tests and brain images were normal. Electroencephalograms showed generalized sharp and slow waves. The autoimmune panel tests were requested. When anti-glutamate receptor antibody was finally reported in her CSF, anti-NMDARE was finally diagnosed. Her symptoms improved by receiving five corticosteroid pulses. Conclusions: In patients with first and acute psychotic symptoms, especially in young individuals with seizures, the possibility of autoimmune disorders should be kept in mind, and complementary tests must be done for autoantibody detection.