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

Prevalence of Post-Stroke Seizures

The overall prevalence of post-stroke seizures is approximately 10% among stroke patients, with early seizures (within 7 days) occurring in 2-16% and late seizures (beyond 7 days) developing in 3-4% of stroke survivors. 1

Overall Prevalence Rates

• Post-stroke seizures affect roughly 10% of all stroke patients, making stroke the most common cause of seizures and epilepsy in elderly populations 1, 2
• The wide range of reported prevalence (2-23% for early seizures) reflects methodological differences across studies, including variations in population selection and stroke severity, with the true risk likely toward the lower end at 2-5% 1, 3

Early vs. Late Seizure Prevalence

• Early seizures (occurring within 24 hours to 7 days post-stroke) affect 2-16% of patients, with most occurring within the first day after stroke onset 1, 2
• Late seizures (occurring beyond 7 days) develop in 3-4% of stroke survivors and carry a higher recurrence risk exceeding 50% 1, 2
• During inpatient stroke rehabilitation specifically, seizure rates are approximately 1.5% 1

Stroke Type-Specific Prevalence

• Ischemic stroke: Seizures occur in approximately 3-7% of patients 4, 2
• Intracerebral hemorrhage (ICH): Clinical seizures occur in 6-16% of patients, with most occurring at or near onset 1, 4
• Subarachnoid hemorrhage: Seizures develop in approximately 9% of patients 4
• Lacunar strokes: Very low seizure risk due to deep location without cortical involvement 1
• Hemorrhagic strokes carry significantly higher seizure risk (25%) compared to ischemic strokes (7.1%) 5

Subclinical Seizure Burden

• Electrographic (subclinical) seizures detected on continuous EEG monitoring occur in 28-31% of select ICH cohorts, even with prophylactic antiseizure medications, highlighting a substantial burden of non-convulsive seizures 1

Critical Risk Factors Affecting Prevalence

• Cortical involvement is the most important risk factor, with 17% of patients with cortical lesions developing seizures compared to only 4.7% with subcortical lesions 1, 5
• Lesion size: Patients with lesions involving more than one lobe have 21.2% seizure risk versus 5.2% for smaller lesions 5
• Hemorrhagic transformation of ischemic stroke significantly increases seizure risk 1
• Pre-existing dementia is associated with increased risk of late seizures 1
• Stroke severity: Strong positive correlation exists between stroke severity and seizure risk, with very low risk in mild strokes 2

Long-Term Epilepsy Development

• Epilepsy (recurrent seizures) develops in 3-4% of all stroke patients overall 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

• Patients with recurrent stroke do not have higher seizure risk during hospitalization compared to first-ever stroke patients (5.1% vs. 4.5%) 6
• Seizure recurrence occurs in approximately 27% of patients who experience an initial post-stroke seizure 5
• The risk of seizure recurrence is lower (<50%) for early seizures compared to remote/late seizures (>50%) 4