A stroke, where blood flow to a part of the brain is interrupted, can cause seizures. This is a concern for stroke survivors, as it can complicate their recovery. Understanding this connection is important for survivors and their caregivers.
The Connection Between Stroke and Seizures
A stroke leads to brain damage, disrupting the brain’s normal electrical activity. Affected brain tissue may die, triggering inflammation. Scar tissue can then form in the damaged area, further altering electrical pathways. This disruption creates an environment where abnormal electrical discharges are more likely, leading to seizures.
Both ischemic strokes, caused by a blood clot, and hemorrhagic strokes, involving bleeding, can lead to seizures. Hemorrhagic strokes, in particular, have a higher likelihood of resulting in seizures than ischemic strokes. The severity of the stroke and its location, especially if it affects the cerebral cortex, also influence the risk of seizures.
Recognizing Post-Stroke Seizures
Post-stroke seizures can present in various ways, not all involving dramatic convulsions. They are often focal (partial) seizures, originating in a specific brain area. These can cause localized symptoms, such as involuntary twitching in a single limb or unusual sensations like strange smells or tastes. Individuals can also experience confusion, altered emotions, or changes in awareness without losing consciousness.
Generalized seizures involve both sides of the brain. These can include loss of consciousness, widespread muscle spasms, or rhythmic jerking movements of the arms and legs. A non-motor generalized seizure might appear as a brief period of blank staring or unresponsiveness. Seizure symptoms vary widely, so prompt medical consultation is important if any unusual behaviors occur.
When Seizures Occur After Stroke
Seizures after a stroke can occur at different times, categorized as “early” or “late” onset. Early post-stroke seizures typically happen within the first week, with many occurring within the initial 24 hours. These early seizures are often related to acute brain injury, such as hypoxia, ischemia, or swelling. The incidence of early seizures ranges from 5% to 15% of stroke patients, with a higher rate in children than adults.
Late post-stroke seizures occur more than one week after the stroke, often peaking around 6 to 12 months later. These are usually associated with longer-term brain changes, such as scar tissue formation or persistent inflammation. While early seizures may not always lead to recurrent seizures, a single late-onset seizure carries a high risk of future seizures, with a 10-year recurrence risk up to 71.5%.
Addressing Seizures After Stroke
Diagnosis of post-stroke seizures typically involves neurological examination, brain imaging, and electroencephalography (EEG). MRI and CT scans show the extent and location of stroke-induced brain damage. An EEG is a diagnostic tool that records the brain’s electrical activity, helping to identify abnormal patterns associated with seizures.
Treatment for post-stroke seizures often involves anti-seizure medications to control or prevent future episodes. Levetiracetam and lamotrigine are frequently preferred as first-line options due to their favorable safety profiles and fewer drug interactions. Other medications, such as carbamazepine, valproic acid, and oxcarbazepine, may also be used, though some older medications might have more side effects or higher discontinuation rates. The decision to discontinue medication is individualized, usually considered after at least two years without seizures, and requires careful medical supervision due to the risk of recurrence. If a seizure is suspected, immediate medical attention is important.