Autoimmune encephalitis presenting as a psychiatric disorder: A diagnostic challenge

Introduction: Autoimmune encephalitis (AE) manifests with various neurologic and psychiatric symptoms. Case presentation: We present a case of a 39-year-old female, postpartum seven months, who presented with altered behaviour, visual hallucinations, and headache without any focal neurological signs. The electroencephalogram showed a focal seizure. However, the possibility of a primary psychiatric condition was considered as there was inadequate response to initial immunosuppressant therapy. Nevertheless, after referring the patient to the psychiatry team, her condition worsened with electroconvulsive therapy. Then the repeat electroencephalogram showed a secondary generalized seizure of temporal lobe origin supporting the diagnosis as AE. She improved after treatment with immune suppressants, intravenous immunoglobulin and plasmapheresis. This case emphasizes the diagnostic difficulty of autoimmune encephalitis, especially when it only presents with psychiatric symptoms.