(733) When Symptoms Deceive: A Case Report on the Diagnostic and Treatment Challenges of NMDA Encephalitis

Introduction: Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis is a rare autoimmune encephalitis affecting young females presenting with acute psychosis, motor impairment, seizures and autonomic instability , which could be mistaken for a primary psychiatric disorder. This condition is often associated with ovarian teratomas. Prompt detection and removal indicates favorable prognosis secondary to the removal of neural tissue in the teratoma.

Description: We present a 20-year-old previously healthy Korean female initially admitted to the psychiatric unit for erratic behavior with withdrawal, severe agitation and hemiballismus. Onset of seizure-like activity prompted electroencephalogram suspicious for extreme delta brush. Lumbar puncture confirmed NMDA receptor antibody positivity, hence she was started on intravenous immunoglobulin (IVIG) and methylprednisolone. CT pelvis showed a right ovarian complex hyperechoic mass (3.2x2.5x3.4 ) likely dermoid cyst, and right lower lobe pneumonia concerning for aspiration, for which she received broad spectrum antibiotics. She promptly underwent a right salpingo-oophorectomy with removal of the dermoid cyst. However, she continued to have recurrent episodic sinus tachycardia to 200 bpm, bradycardia to 40 bmp, high grade fevers, and apnea requiring mechanical ventilation and vasopressor support. Hyperthermia to 110°F ensued refractory to ice immersion and arctic sun. The patient went into cardiac arrest after an episode of arrhythmia with no return of spontaneous circulation despite resuscitative efforts. Post-mortem report revealed that the cause of death was septic shock due to acute left lower lobe pneumonia.

Discussion: In this case report, we describe an unfortunate case of a young woman who demonstrated profound autonomic dysfunction despite early detection and teratoma removal. As recommended, she was treated with high-dose steroids and IVIG given the high response rate when used in combination. In those who failed to improve within two weeks, Rituximab is the preferred next immunotherapy. NMDAR encephalitis complicated with significant autonomic disturbances requiring intensive care unit remains a predictor of poor prognosis.