Duration of refractory status epilepticus and outcome: loss of prognostic utility after several hours

Outcome for patients with status epilepticus (SE) depends strongly on etiology. Duration of SE is also predictive, at least in the first 2 h, but beyond this it is unclear that duration of SE influences outcome significantly. We sought to determine the influence of duration of SE on outcome in patients with prolonged SE, and to compare this influence with that of other factors.

We reviewed the clinical course and outcome of 119 patients with SE, diagnosed by both clinical manifestations and electroencephalography (EEG) evidence. Using univariate and multivariate analyses, we sought predictors of outcome (survival vs. death or vegetative state) among age, etiology (epilepsy, anoxia or severe hypoxia, or other), presence of earlier epilepsy, multiple medical problems, presentation in coma, and type of SE (focal or generalized).

Median duration of SE was 48 h. Survival was greater with a shorter duration, especially when <10 h (69% vs. 31% for longer duration; p < 0.05). Epilepsy as the etiology, and an earlier diagnosis of epilepsy offered a favorable prognosis (p < 0.01), but only the former on multivariate analysis. Coma and SE caused by anoxia/hypoxia were unfavorable factors. Once corrected for etiology, presentation in coma, and type of SE (focal or generalized), duration of SE did not have a significant effect on outcome. Overall mortality was high, 65%, but 10 patients survived SE lasting over 3.5 days.

A duration of <10 h was associated with better outcome in SE, but this was not significant once etiology, presentation in coma, and type of SE were accounted for. Etiology of SE is still the primary determinant of outcome. Unless it follows anoxia, prolonged SE should not be considered a hopeless condition.