Abstracts

Rationale: We report a patient with anti-NMDA receptor encephalitis associated with a silent ovarian teratoma presenting with nonconvulsive status epilepticus (NCSE) characterized electrographically by highly atypical ictal paroxysmal fast activity (PFA). Methods: We describe the clinical history and EEG findings of a unique patient admitted to the University of Maryland Medical Center with NCSE and anti-NMDA receptor encephalitis. Relevant laboratory, pathologic, and imaging data collected are examined. In addition, this case is considered in the broader context and literature regarding anti-NMDA encephalitis due to ovarian teratoma and its association with NCSE.Results: A previously healthy 19 year old African-American woman presented with several days of psychosis and seizures to an outside hospital. She was transferred for further management and workup of suspected refractory status epilepticus. Electroencephalographic seizures captured during continuous video EEG monitoring were manifested electrographically by highly atypical generalized paroxysmal fast activity evolving sometimes into generalized high voltage spike activity and spike and wave activity. She was diagnosed with NCSE and aggressively treated with antiepileptic drugs (AEDs). MRI of the brain showed mild FLAIR hyperintensity within the heads of the bilateral caudate nuclei and in portions of the bilateral cerebral cortex. Based on concern for autoimmune mediated encephalitis, an abdominal ultrasound was performed and demonstrated an apparent ovarian teratoma. Eleven days after presentation to our institution the patient had a right salpingo-oopherectomy for the lesion; pathology was consistent with a cystic mature teratoma. NMDA receptor antibody testing was positive. In addition to treatment by resection of the teratoma, she continued to be treated with AEDs, and was also treated with steroids, plasmapheresis, and intravenous immunoglobulin. The status epilepticus resolved, and she began to recover, however, now four weeks following presentation some cognitive impairment persists.Conclusions: Anti-NMDA receptor encephalitis associated with an ovarian teratoma can present as nonconvulsive status epilepticus with atypical ictal paroxysmal fast activity. Even with such atypical EEG findings, an anti-NMDA mediated type of NCSE should be suspected and identified promptly to assure that treatment with AEDs, removal of the teratoma, and appropriate immune therapy is instituted as early as possible to maximize the probability of a favorable outcome.