Prognosticating acute symptomatic seizures using two different seizure outcomes.

PURPOSE

This study examined the profiles and prognosis of first acute symptomatic seizure (ASS). Because seizure recurrences may occur in the setting of a persisting or reemerging acute symptomatic cause or in the setting of an unprovoked seizure, we documented the prognosis of ASS in terms of acute symptomatic seizure (AS) or unprovoked seizure (US) recurrence.

METHODS

We conducted a prospective study of patients with suspected seizures between April 2004 and December 2005. Patients were classified according to medical history taking, routine clinical evaluation, and expert adjudication, and they were followed for a minimum of 2 years or until death. The Kaplan-Meier method and univariate/multivariate statistical analysis were used to determine prognosis.

RESULTS

One hundred five patients with first-ever ASS were identified. For many, first ASS was associated with status epilepticus (29.5%), multiple-onset (>1 seizure within 24 h on day of presentation) (35.2%), and multiple etiologies (22.9%), with a mortality of 30% at 2 years (Kaplan-Meier method). Using AS as outcome, the risk of recurrence following an ASS was 32% at 2 years [mean time to recurrence 20.5 days with epileptiform electroencephalography (EEG) being an independent predictor; p = 0.005, odds ratio (OR) 16, 95% confidence interval (CI) 4.09-62.7]. Using US as outcome, the risk of recurrence following an ASS was 12% at 2 years.

DISCUSSION

Although ASS did not associate with a high rate of US recurrence, we demonstrated that ASS was often followed by another AS. This may have implication for short- to medium-term antiepileptic agent therapy, especially when the acute symptomatic cause takes a long time to treat, is prone to reemergence, or is irreversible.