Acute psychosis as a harbinger of a tumor: A case of anti-N-methyl-D-aspartate receptor encephalitis

Abstract

An obese but otherwise healthy 22-year-old female presented to the hospital with an episode of acute psychosis. On exam the patient was febrile and had labile systolic blood pressure. Urine drug screen and infectious workup were negative. A CSF Anti-N-methyl-D-aspartate (Anti-NMDA) receptor antibody was positive. Brain magnetic resonance imaging (MRI) showed hyperintensity in the left hippocampus on diffusion weighted imaging (DWI). The patient was started on prednisone, intravenous immunoglobulins, and rituximab. Hospital course was complicated by seizures and autonomic instability, requiring prolonged stay in the ICU. Cognitive, motor, and autonomic function gradually improved with therapy. Magnetic resonance imaging of the pelvis revealed a 3 cm × 3 cm left ovarian teratoma that was removed with oophorectomy. The patient was discharged to rehab hospital for continued treatment and physical therapy.