Seizure Characteristics, Outcome, and Risk of Epilepsy in Pediatric Anti-N-Methyl-d-Aspartate Receptor Encephalitis

Abstract

BackgroundWe identified seizure characteristics, long-term outcome, and predictors of persistent seizures in children with anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis. MethodData were analyzed from patients with anti-NMDAR encephalitis who presented with seizures at our center between August 2012 and June 2018. ResultsSixty-two of 86 patients with anti-NMDAR encephalitis experienced seizures. Seizures occurred within two weeks of disease onset in 58 of 62 (93.6%) patients; 36 of 62 (58.1%) had seizures as the initial symptom. Males were more likely to exhibit seizures as the initial symptom (P = 0.039). More than a quarter of patients (17 of 62, 27.4%) manifested two or more seizure types. Focal seizures were the most common (46 of 62, 74.2%). Status epilepticus occurred in 27 of 62 (43.5%) patients, and nonconvulsive status epilepticus, in two of 62 (3.2%) patients. No patient developed refractory status epilepticus. No systemic tumors were found. Electroencephalographic abnormalities included background slowing (77.4%), absence of a posterior dominant rhythm (62.9%), interictal epileptic discharges (50.0%), and extreme delta brush (6.5%). In the acute phase, 45 patients (45 of 62, 72.6%) received antiepileptic drugs. Persistent seizures occurred in only five of 62 (8%) patients. On univariate analysis, status epilepticus and combination antiepileptic drug treatment were associated with persistent seizures, but neither independently predicted persistent seizures. ConclusionsMultiple seizure types may develop at any stage of anti-N-methyl-d-aspartate receptor encephalitis. Refractory status epilepticus, systemic tumors, and extreme delta brush in electroencephalography are rare in pediatric patients. Anti-NMDAR encephalitis–associated seizures appear to have good prognosis, without the need for long-term antiepileptic drug treatment.