Can stroke cause seizures?

Can Stroke Cause Seizures?

Yes, stroke definitively causes seizures in approximately 10% of patients, with hemorrhagic strokes carrying nearly double the risk compared to ischemic strokes. 1, 2

Epidemiology and Risk Magnitude

Seizures occur in 8.9% of all stroke patients overall, with significant variation by stroke type: 2

• Hemorrhagic stroke: 10.6-25% develop seizures 1, 3, 2
• Ischemic stroke: 7.1-8.6% develop seizures 3, 2
• Hemorrhagic stroke carries an 85% increased risk (hazard ratio 1.85) compared to ischemic stroke 2

The reported range of 2-23% in early studies reflects methodological differences, with the true risk toward the lower end at 2-5% for early seizures. 1, 4

Timing Classification: Critical for Management Decisions

Early seizures (within 24 hours to 7 days post-stroke):

• Occur in 2-16% of patients 5, 6
• Usually partial seizures with or without secondary generalization 1
• Most occur within the first 24 hours 1
• Typically self-limiting and due to acute metabolic disturbances 6
• Recurrence risk: 20-33% 1, 6

Late seizures (beyond 7 days):

• Occur in 3-4% of stroke survivors 5
• Indicate development of epileptogenic focus 6
• Carry >50% recurrence risk 6
• A single late seizure has 71.5% recurrence risk at 10 years, meeting criteria for post-stroke epilepsy 7

High-Risk Features That Increase Seizure Likelihood

Cortical involvement is the single most important risk factor:

• Cortical lesions: 17% seizure rate 3
• Subcortical lesions: 4.7% seizure rate 3
• Cortical location increases risk 2-fold for ischemic stroke (HR 2.09) and 3-fold for hemorrhagic stroke (HR 3.16) 2

Other significant risk factors:

• Lesions involving more than one lobe: 21.2% vs. 5.2% for smaller lesions 3
• Hemorrhagic transformation of ischemic stroke 1, 6
• Pre-existing dementia (increases late seizure risk) 1, 6
• Greater stroke severity and disability (HR 2.10) 2
• Lacunar strokes carry very low seizure risk 5, 6

Mechanism: Why Strokes Cause Seizures

Early seizures result from acute metabolic disturbances, ionic shifts, and cellular injury in the acute phase. 6 Late seizures develop from epileptogenic foci created by gliosis and cortical scarring in the chronic phase. 6 Status epilepticus is uncommon. 1

Critical Management Principles

For active seizures:

• First-line: Lorazepam 4 mg IV at 2 mg/min 5, 4
• Second-line: Levetiracetam 30 mg/kg IV over 5 minutes if seizures continue 5

For single early seizures (≤24 hours):

• Do NOT initiate long-term anticonvulsants 5, 4
• Monitor for recurrence during routine vital signs 5, 4

For recurrent seizures:

• Initiate long-term anticonvulsant therapy per standard seizure protocols 5, 4
• Levetiracetam is preferred due to better tolerability and lack of drug interactions 5
• Avoid phenytoin due to worse cognitive outcomes and significant drug interactions 5

Common Pitfalls to Avoid

Never use prophylactic anticonvulsants in stroke patients without documented seizures—this approach has no preventive benefit and is associated with poorer functional recovery, worse cognitive outcomes, and impaired neural plasticity mechanisms essential for stroke recovery. 1, 5, 6, 4

The distinction between early and late seizures is crucial because they carry vastly different recurrence risks and treatment implications. 6, 7 A single self-limiting early seizure requires observation only, while recurrent or late seizures mandate long-term treatment. 5, 4