Analyze clinical and electrographic characteristics of patients with autoimmune epilepsy, and evaluate the effect of early diagnosis and treatment on reduction of seizure frequency.

Observational retrospective case series, conducted using electronic medical data from two teaching hospitals. Clinical data was collected from 2008 to 2013. Cases of new onset seizures were selected based on the presence of laboratory evidence of autoimmunity.

34 hospitalized patients who presented predominantly due to seizures with concern for autoimmune etiology were identified. Mean age of patients was 44.94 years and 64.7% were males. Autoimmune antibodies were detected in 76.5% (26) of patients as follows: VGKc (8); NMDA-R (7); anti-thyroid (5); GAD (4); GABA_B (2). 22 patients had unilateral temporal lobe onset and 4 had bilateral temporal lobe onset, while 8 had extra-temporal onset/multiple ictal foci. Median number of seizures during initial prolonged vEEG monitoring was 8 (range 0–48); median number of anti-seizure medications used was 2 (range 1–5). 9 patients had an underlying malignancy. 94.1% (32) patients received immunomodulation, as follows: high dose corticosteroids (96.8%), plasmapheresis (62.5%), IVIG (34.4%), rituximab (21.8%), mycophenolate (15.6%), cyclophosphamide (12.5%). 63.3% (19) participants achieved ≥50% seizure reduction (Responder Rate) at first clinic visit. Patients without malignancy had better seizure control (p < 0.05). Time from symptom onset to diagnosis (p < 0.005) and symptom onset to immunomodulation (p < 0.005) was significantly lower among patients who achieved responder rate (RR).

This study highlights certain important clinical and electrographic aspects of autoimmune epilepsy, and the significance of early diagnosis and initiation of immunomodulatory therapy.