Risk factors for a first epileptic seizure after stroke: A case control study

Introduction: The risk of seizures increases after stroke, but not all risk factors are known. We aimed to identify factors that increase the risk of a first seizure after a stroke. Methods: Multicenter case-control study of 161 patients with a first seizure after stroke (105 provoked/acute and 56 unprovoked/remote symptomatic) matched to 279 hospital stroke controls by center, gender, age and timing of stroke. Results: The risk of first seizure (odds ratio (OR), 95% confidence limits (CL)) was 3.6 (2.4-5.5) for cortical involvement, 2.5 (1.2-5.3) for multiple CT-scan lesions, 2.4 (1.5-3.9) for supratentorial lesions, 2.4 (1.6-3.7) for prior lesions on CT-scan, 2.1 (1.1-4.7) for family history of seizures, 2.0 (1.1-3.6) for use of epileptogenic drugs, 1.7 (1.0-2.9) for large lesions, 1.6 (1.0-2.8) for hemorrhagic lesions, and 1.4 (1.0-2.2) for cortical atrophy. After multivariate analysis, including all the factors significant in univariate analysis, the strongest independent predictor of a first seizure was cortical involvement (OR 3.3; 95% CL = 2.1-5.0), followed by prior lesions (2.2; 1.4-3.4) and hemorrhagic stroke (1.8, 1.0-3.2). The multivariate analysis model for remote symptomatic seizures included cortical involvement, large size, and prior lesions; the model for acute seizures included cortical involvement, alcohol consumption > 50 g/day, hemorrhagic stroke, and prior lesions on CT-scan. Discussion: Cortical involvement, the presence of prior lesions on CT-scan, and hemorrhagic lesion are the most important risk factors for a first-ever seizure after stroke.