What is the prevalence of post-stroke seizures among stroke patients?

Prevalence of Post-Stroke Seizures

The prevalence of post-stroke seizures is approximately 10% overall, with early seizures (within the first week) occurring in 2-16% of patients and late seizures developing in 3-4% of stroke survivors. 1, 2

Early vs. Late Seizure Prevalence

Early Seizures (Within First Week)

• Early seizures occur in 2-23% of stroke patients, with the true risk toward the lower end of this range (2-5%). 1
• The majority of early seizures occur within the first 24 hours after stroke onset. 1, 3
• During inpatient stroke rehabilitation specifically, seizure rates are approximately 1.5%. 1
• For intracerebral hemorrhage (ICH) specifically, early clinical seizures occur in up to 16% of patients, with most occurring at or near onset. 1

Late Seizures (Beyond First Week)

• Late seizures develop in 3-4% of stroke patients overall. 2
• Estimates for late seizure incidence vary widely in the literature from 3% to 67%, reflecting differences in study populations and follow-up duration. 1
• Late seizures carry a higher recurrence risk (>50%) compared to early seizures (<50%). 3, 4

Stroke Type-Specific Prevalence

Hemorrhagic Stroke

• Hemorrhagic stroke carries significantly higher seizure risk at 6-25% compared to ischemic stroke. 2, 4, 5
• Intracerebral hemorrhage patients show clinical seizures in up to 16% of cases. 1
• Electrographic (subclinical) seizures detected on continuous EEG occur in 28-31% of select ICH cohorts, even with prophylactic antiseizure medications. 1

Ischemic Stroke

• Ischemic stroke carries approximately 3-7% risk of developing seizures. 2, 4, 5
• Lacunar strokes have very low seizure risk. 1

Critical Risk Factors Affecting Prevalence

Cortical Involvement

• Cortical involvement dramatically increases seizure risk to 17% compared to 4.7% for subcortical lesions. 5
• Cortical involvement is the most important risk factor for early seizures in ICH. 1

Lesion Size

• Large lesions involving more than one lobe carry 21.2% seizure risk versus 5.2% for smaller lesions. 5
• Stroke severity shows strong positive correlation with seizure risk; mild strokes have very low risk. 2

Other Risk Factors

• Pre-existing dementia increases the probability of late seizures. 1, 3
• Hemorrhagic transformation of ischemic stroke increases seizure risk. 3

Long-Term Epilepsy Development

• Epilepsy (recurrent seizures) develops in 3-4% of all stroke patients. 2
• Approximately one-third of patients with early-onset seizures develop epilepsy. 2
• Approximately one-half of patients with late-onset seizures develop epilepsy. 2
• In young ICH patients (18-50 years), epilepsy occurs in up to 10%; the risk may be lower in older patients. 1
• Status epilepticus develops in less than 1% of stroke patients. 4

Important Clinical Context

The wide range of reported prevalence (2-23% for early seizures, 3-67% for late seizures) reflects methodological differences across studies, including: 1

• Population selection (hospital-based vs. community-based studies)
• Inclusion of subclinical seizures detected only on EEG monitoring
• Stroke severity and type distribution in study cohorts
• Duration and completeness of follow-up

Common pitfall: Do not assume all stroke patients need seizure prophylaxis based on these prevalence figures—prophylactic antiseizure drugs are not recommended and may worsen outcomes. 1, 6, 7