Seizure outcomes in patients with anti-NMDAR encephalitis: A follow-up study

Abstract

Objective: To evaluate the long-term seizure outcome and potential factors associated with seizure outcome in patients with anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis.

Methods: In the setting of a prospective, single-center, longitudinal cohort study, 109 patients were evaluated with ongoing follow-up. Patients underwent clinical evaluation every 3 months. Seizure outcomes and the potential risk factors were assessed with a median follow-up of 24 months (6-60 months).

Results: Of 109 patients (47 men; 62 women) with anti-NMDAR encephalitis, 88 patients (80.7%) had reported seizures at acute phase, including single seizure (17/88, 19.3%), repetitive seizures (27/88, 30.7%), nonrefractory status epilepticus (22/88, 25%), refractory status epilepticus (SE; 13/88, 14.8%), and super refractory status epilepticus (9/88, 10.2%). Seizure was more likely to recur in patients with tumor presence, status epilepticus (SE) development, coma, or intensive care unit (ICU) admission in the acute phase (p < 0.05). Seizure freedom was achieved within 2 years in all patients. More than 80% of the whole cohort with acute seizures had their last seizure within 6 months of disease onset.

Significance: Seizure is a common feature in the acute stage of anti-NMDAR encephalitis but not thereafter. The presence of tumor, SE, coma, and/or ICU admission in the acute phase predicts early seizure occurrence after the acute phase. Seizure freedom was typically achieved in our follow-up, and long-term use of antiepileptic drugs may not be necessary.

Keywords: Anti-NMDAR encephalitis; Antiepileptic drugs; Epilepsy; Seizures.