Seizures Following Ischemic Stroke: Frequency of Occurrence and Impact on Outcome in a Long-Term Population-Based Study

Background and purpose: Seizures are a known complication of ischemic stroke (IS). This study assesses the long-term incidence and characteristics of poststroke seizures in a well-defined population.

Methods: Using the Rochester Epidemiology Project medical records-linkage system, we identified all incident cases of IS among Rochester, Minnesota, residents from 1990 to 1994 and followed the patients in the comprehensive medical record through March 2014. All patients with poststroke seizures were identified, and data regarding incident IS, seizures, and status at last follow-up were analyzed.

Results: We identified 489 patients with first IS. Mean follow-up was 6.5 (standard deviation 6.3) years. New onset seizures occurred in 35 patients (7.2%). Patients with poststroke seizure did not differ from those without in terms of IS etiologic subtype (P = .44) or IS risk factors (P > .05). Early seizures (within 14 days of index stroke) developed in 14 patients (40%), the majority within the first 24 hours (n = 9, 64.3%). The median time of seizure onset for the remaining 21 patients was 13.8 months. Functional outcome, as measured by modified Rankin Scale (mRS), was worse following development of poststroke seizures (mean mRS score 2.9 after IS, 3.3 following index seizure; P = .005), and mortality was higher as well, even after adjusting for IS etiologic subtype (HR 1.52, 95% confidence interval 1.07-2.16, P = .02).

Conclusion: Development of poststroke seizures is an infrequent but significant complication of IS, portending a worse short-term functional outcome and a higher long-term mortality rate. Seizure occurrence did not differ based on IS etiologic subtype or stroke risk factors.