Abstracts

Rationale: EEG pattern in patients with anti-NMDA receptors encephalitis may have not been completely characterized. This report is a contribution to the description of clinical and electrographic features of seizures in patients with anti-NMDA receptors encephalitis.Methods: We identified four cases of anti-NMDA receptor encephalitis in our institution during the last 5 years and systematically described their clinical presentation and seizures as recorded by continuous video EEG monitoring.Results: Four patients were seen during the study period and all (100%) had a clinical seizure. Three patients had a partial onset seizure that all progressed to a generalized tonic and clonic seizure. One patient had a generalized tonic and clonic seizure with subsequent progression to non convulsive status epilepticus. Two patients had breakthrough seizures after the acute phase. Initial clinical presentation was subtle including insomia in three patients and non specific (gastro-intestinal symptoms) in one patient. Psychiatric manifestations (usually visual hallucinations) were present in all 4 participants at the early phase of the disease. Duration of continuous video EEG recording ranged from 3 to 92 days. Generalized delta slowing with or without extreme delta brush were the most common background EEG activities. Electrographic seizures were frequently focal with or without clinical manifestations of seizures. One patient did not recover from non convulsive status epilepticus and died.Conclusions: The clinical semiology of seizure in patients with anti-NMDA receptor encephalitis is ranging from partial onset to non convulsive status epilepticus with possible breakthrough seizures after the acute phase . The most common EEG background seems to be a generalized delta slowing with or without delta brush. Non convulsive status, especially when medically refractory, may signal an ominous outcome. Our study adds to the body of clinical and electrographic characterization of seizure in anti-NMDA receptor encephalitis patients.