Watershed infarctions are more prone than other cortical infarcts to cause early-onset seizures

Early-onset seizures(ESs) have been reported in 2% to 6% of strokes. Most previous studies have been retrospective and did not systematically perform cerebral magnetic resonance imaging (MRI).

To determine the prevalence and determinants of ESs in a prospective cohort.

Prospective cohort study.

Stroke unit in an academic hospital.

Six hundred sixty-one consecutive individuals admitted to our stroke unit during an 18-month period for suspected stroke.

Initial investigations systematically included cerebral MRI. Among patients with MRI-confirmed cerebral infarction, individuals with ES, defined as occurring within 14 days of stroke, were identified.

Three hundred twenty-eight patients had MRI-confirmed cerebral infarcts and 178 had cortical involvement. The ESs, all initially partial seizures, occurred in 14 patients (4.3%) and at stroke onset in 5 patients. The ESs occurred exclusively in patients with cortical involvement (P <.001). With infarcts involving the cerebral cortex, there was a higher risk of ESs in watershed infarctions than in territorial strokes (6 of 26 [23.1%] vs 8 of 152 [5.3%], P = .007). Logistic regression analysis showed an almost 4-fold increased risk of ES in patients with watershed infarctions compared with other cortical infarcts (odds ratio, 4.7; 95% confidence interval, 1.5- 15.4; P = .01). Age, sex, diabetes mellitus, hypertension, smoking, National Institutes of Health Stroke Scale score, and cardioembolic origin were not significant risk factors for ES.

The cortical hemispheric location of ischemic strokes is associated with a higher risk of ES. Among these patients, the watershed mechanism is a strong and independent determinant of stroke-related ES.