When mania is not primary: A case report on anti-NMDA receptor encephalitis presenting during early pregnancy

Anti-NMDA receptor encephalitis is the most common subtype of autoimmune encephalitis, predominantly affecting young females and often presenting with psychiatric symptoms, leading to diagnostic challenges. We report a 27-year-old pregnant female presenting with first-episode mania and recurrent seizures. During hospitalisation, she developed drowsiness, orofacial dyskinesia and emerging catatonia, raising suspicion of autoimmune encephalitis. Initial EEG, MRI brain and CSF studies were normal, but CSF testing later confirmed anti-NMDA receptor antibodies. She was treated with intravenous methylprednisolone followed by mycophenolate mofetil resulting in significant recovery. This case highlights the need to consider autoimmune encephalitis in new-onset psychiatric presentations with neurological features.