Can Seizures Cause Stroke?
No, seizures (convulsions) do not cause strokes—rather, strokes can cause seizures. The relationship is unidirectional: stroke is a well-established cause of seizures, but there is no evidence that seizures themselves trigger cerebrovascular events 1.
Understanding the Stroke-Seizure Relationship
Stroke as a Cause of Seizures
Strokes are among the most common causes of epilepsy in adults, particularly in the elderly, accounting for 30-40% of all epilepsy cases in older populations 2.
Seizures occur in approximately 5-10% of stroke patients, with some studies reporting rates as low as 2.3% for seizures at stroke onset 2, 3.
The timing matters significantly: Seizures are classified as "early" (within 24 hours to 4 weeks post-stroke) or "late" (beyond 4 weeks post-stroke) 1.
Why Seizures Don't Cause Strokes
Seizures represent abnormal electrical activity in the brain, not vascular occlusion or hemorrhage that defines stroke 4.
The pathophysiology is fundamentally different: Strokes result from interrupted blood flow (ischemic) or bleeding (hemorrhagic), while seizures result from neuronal hyperexcitability 5, 4.
Critical Clinical Distinction: Seizures at Stroke Onset
The Diagnostic Challenge
Seizures can occur at the immediate onset of stroke in approximately 40% of early seizure cases, creating a diagnostic dilemma where the seizure may be mistaken for the primary problem rather than recognizing the underlying stroke 5, 3.
Seizures at onset are associated with more severe strokes (higher NIHSS scores) and hemorrhagic strokes, but they do not preclude acute stroke treatment 3.
The presence of seizure activity should prompt immediate stroke evaluation, including brain imaging with non-contrast CT or MRI, not delay it 1.
Management Priorities
Assessment in the acute phase must include evaluation for both seizure activity AND stroke, as these can coexist 1.
New-onset seizures at the time of suspected stroke should be treated with short-acting medications (e.g., lorazepam IV) if not self-limiting, but this should not delay stroke imaging or treatment decisions 1.
Brain imaging is essential to differentiate between postictal deficits and actual stroke, as seizures with postictal symptoms can mimic stroke presentation in up to 20% of suspected stroke cases 4.
Post-Stroke Seizure Management
Immediate Post-Stroke Seizures (Within 24 Hours)
A single, self-limiting seizure occurring within 24 hours of stroke onset should NOT be treated with long-term anticonvulsant medications 1.
Patients should be monitored for recurrent seizure activity during routine vital sign monitoring 1.
Prophylactic anticonvulsant use is not recommended and may cause harm with negative effects on neurological recovery 1.
Recurrent or Late Seizures
Recurrent seizures or seizures occurring beyond the immediate post-stroke period should be treated according to standard seizure management protocols 1.
EEG monitoring and investigation for other precipitating factors (infections, metabolic derangements) may be warranted 1.
Key Clinical Pitfalls to Avoid
Do not assume a seizure rules out stroke—seizures can be the presenting symptom of acute stroke and should trigger immediate stroke evaluation 5, 3, 4.
Do not delay thrombolysis or thrombectomy for seizure evaluation—seizure treatment and stroke treatment should proceed in parallel when both are present 1, 3.
Do not start prophylactic anticonvulsants after stroke—there is no evidence of benefit and some evidence of harm 1.
Do not confuse postictal deficits with stroke recurrence—neuroimaging is essential to differentiate these conditions 4.