Acute seizures are associated with a higher mortality at 30 days after stroke, according to the results of a population-based study reported online in the January 31 issue of Epilepsia and will appear in the June 2008 print issue.
“Cerebrovascular disease has long been recognized as a risk factor for the development of epilepsy and it is considered the most common identified antecedent condition that results in symptomatic epilepsy in the elderly,” write Jerzy P. Szaflarski, from the University of Cincinnati Academic Health Center in Ohio, and colleagues. “The incidence of seizures within 24 h of acute stroke has not been studied extensively. We aimed to establish the incidence of acute poststroke seizures in a biracial cohort and to determine whether acute seizure occurrence differs by race/ethnicity, stroke subtype, and/or stroke localization.”
The investigators identified all stroke cases occurring between July 1993 and June 1994 and in 1999 in the population of the greater Cincinnati metropolitan region, after excluding patients with a previous history of seizures or epilepsy.
Of 6044 patients who had a stroke and who had no previous history of seizure, 190 (3.1%) had seizures within the first 24 hours of stroke onset. Among patients with intracerebral hemorrhage or subarachnoid hemorrhage, 8.4% had a seizure within the first 24 hours of stroke onset (P ≤ .0001) compared with all other stroke subtypes. For ischemic stroke, incidence of seizures was higher for cardioembolic stroke compared with small or large vessel ischemic stroke (P = .02).
Although patients with seizures had higher mortality than did patients without seizures (P < .001), seizures were not an independent risk factor for mortality at 30 days after stroke. Hemorrhagic stroke, younger age, and prestroke Rankin score of 1 or more were independent risk factors for seizure development, whereas race/ethnicity or ischemic stroke localization were not associated with risk for seizure development.
Limitations of this study include biracial population not including patients of Hispanic, Native American, or Asian ethnicity; retrospective data collection; and possible overestimation or underestimation of the incidence of seizures.
“The overall incidence of acute seizures after stroke was 3.1%, with a higher incidence seen in hemorrhagic stroke, younger patients, and those presenting with higher prestroke Rankin scores,” the study authors write. “Acute seizures were associated with a higher mortality at 30 days after stroke.”
The authors have disclosed no relevant financial relationships.
Epilepsia. Published online January 31, 2008. 2008;00:000-000.
Clinical Context
Seizures occur in approximately 10% of patients after stroke, and half of these seizures occur during the first 1 to 2 weeks following stroke. The effect of these early seizures on the risk of mortality is controversial, as some research has demonstrated an increased risk of death associated with early seizures following stroke, and other studies have not. In a study by Kilpatrick and colleagues of 62 patients with stroke, published in the May 1992 issue of Archives of Neurology, patients with an early seizure after stroke experienced a 3-fold increase in the absolute risk of subsequent stroke compared with stroke patients without early seizure.
The current study focuses on the incidence of seizure within the first 24 hours after stroke, risk factors for seizure, and the prognosis after seizure.
Study Highlights
* Study data were drawn from 19 hospitals in the Cincinnati metropolitan area. Patients with a billing code for stroke between 1993 and 1994 and in 1999 were included in the study, and patients admitted for transient ischemic attack were also part of the study. Only patients with clinical evidence of a stroke were included in the study.
* A study nurse examined patient charts for the occurrence of seizures during the first 24 hours after the onset of stroke symptoms. Risk factors in the patient history for seizure were examined.
* Researchers also assigned stroke category and the mechanism of stroke.
* The main study outcomes were the incidence of seizure within the first 24 hours after stroke, risk factors for seizure, and the prognosis after seizure.
* 6044 stroke events met criteria for the current study; 88.1% of patients had an ischemic event, and 11.8% had a hemorrhagic stroke.
* The incidence of poststroke seizures within 24 hours was 3.1%.
* Patients with seizures were younger and had a lower initial Glasgow Coma Scale score and a higher National Institutes of Health Stroke Scale score.
* The incidence rates of acute seizures among patients with ischemic and hemorrhagic stroke were 2.4% and 8.4%, respectively.
* Patients with cardioembolic stroke experienced a higher rate of seizures compared with patients with small or large vessel ischemic disease.
* The absolute rates of all-cause mortality at 30 days were 32.1% and 13.3% among patients with and without seizures, respectively. The presence of poststroke seizure increased the risk of 30-day mortality 2-fold, although early seizure was not an independent risk factor for 30-day mortality.
* On fully adjusted analyses, younger age, hemorrhagic stroke, and a prestroke Rankin score of 1 or more were significant and independent predictors of seizure occurrence within the first 24 hours after stroke, but race/ethnicity and the anatomic location of stroke were not.
Pearls for Practice
* Seizures following stroke occur in approximately 10% of patients, with half of these seizures occurring during the first 2 weeks after stroke. Although early seizure after stroke may not independently predict an increased risk of mortality, early seizures do appear to predict an increased risk of subsequent seizures.
* In the current study, younger age, hemorrhagic stroke, and a prestroke Rankin score of 1 or more were significant and independent predictors of seizure occurrence within the first 24 hours after stroke, but race/ethnicity and the anatomic location of stroke were not.
Reviewed by Dr. Ramaz Mitaishvili
Glendale, CA
