Severe relapse of anti-NMDA receptor encephalitis 5 years after initial symptom onset

Abstract Anti-NMDAR encephalitis is characterized by abnormal behavior, cognitive dysfunction, seizures, disturbance of consciousness, central hypoventilation, and movement disorders, with a tendency to occur in younger women. Immunotherapy and tumor removal, where applicable, are effective for this disorder. However, previous papers have shown neurological relapse in 12–24% of cases. We present a case of anti-NMDAR encephalitis relapse 5 years after the initial episode. Although the relapse was much more severe than the initial episode, she recovered with aggressive therapy using first- and second-line immunotherapies. Anti- NMDAR encephalitis could relapse with a more severe clinical course after several years. Aggressive immunotherapy including cyclophosphamide must be necessary even for recurrent cases of anti-NMDAR encephalitis.