Emergency treatment delay and underdosing are associated with poor outcome in non-convulsive status epilepticus.

Nonconvulsive status epilepticus (NCSE) is difficult to recognize in the emergency department (ED), where onset is often unknown and treatment may be delayed. To what extent treatment timing and dose adequacy are associated with outcome in NCSE remains debated. In this single-center electroencephalography (EEG)-based study, adults with NCSE diagnosed in the ED were included. Timing was measured using ED arrival as a temporal anchor. Outcomes were failure to return to baseline at discharge and in-hospital mortality. Among 74 patients (mean age 66.8), 38 (51.4%) failed to return to baseline and 14 (18.9%) died. ED benzodiazepines (BDZs) were administered in 43 patients (58.1%) and anti-seizure medications (ASMs) in 71 (95.9%). Median times to BDZ and ASM administration were 184 and 223 min, respectively. After adjustment for Status Epilepticus Severity Score (STESS), potentially fatal etiology, and premorbid modified Rankin Scale score, time to ASM (odds ratio [OR]: 1.11 per hour; 95% confidence interval [CI]: 1.01-1.22; p = .037) and ASM underdosing (OR: 3.43; 95% CI: 1.10-10.68; p = .034) were independently associated with failure to return to baseline, with time to BDZ showing a non-significant trend. BDZ underdosing was not associated with functional outcome, and no treatment variable was associated with mortality. These findings support early EEG-based recognition and rapid, adequately dosed ASM treatment as key targets in ED-NCSE management.