Postinfarction seizures. A clinical study.

We retrospectively studied 90 patients with postinfarction seizures to determine the clinical features (onset, number, type), prognosis, and electroencephalographic and computed tomographic findings; we included infarctions of all etiologies. Thirty-three percent of the 90 seizures appeared early (within 2 weeks after the infarction), and 90% of the 30 early seizures appeared within 24 hours after the infarction. Seventy-three percent of the 90 seizures occurred within the first year, and only 2% occurred greater than 2 years after the infarction. Fifty-six percent of the 90 seizures were single, and status epilepticus was seen in only 8%. Early-onset seizures were more likely to be partial (57% of 30); late-onset seizures were more likely to be generalized (65% of 60). Thirty-nine percent of the 90 initial seizures recurred, and there was no significant difference in recurrence rate between early- or late-onset initial seizures. Twenty-two percent of the 90 initial seizures became multiple recurrent seizures, and we could identify a precipitating factor in 86% of the 35 recurrent seizures. The most common electroencephalographic abnormality in the 61 patients so examined was focal slowing (61%), but recurrent seizures occurred in 100% of the four patients with periodic lateralized epileptiform discharges and in 75% of the eight patients with diffuse slowing. Computed tomography in 61 patients showed that large infarctions were associated with early (p less than 0.021) and multiple (p less than 0.05) seizures. Deep infarctions on computed tomograms (cortical infarctions extending to subcortical structures) tended to cause recurrent seizures (p less than 0.057). Seizures in 88% of the 90 patients could be managed with monotherapy.