A seizure is a sudden, uncontrolled electrical disturbance in the brain, leading to changes in movement, behavior, sensation, or awareness. A stroke occurs when blood flow to the brain is interrupted, depriving brain cells of oxygen and nutrients, causing them to die. Their relationship is often misunderstood. This article clarifies whether seizures can cause strokes and explains the nuances of their connection.
When Seizures Mimic Stroke
After seizures, individuals may experience temporary neurological deficits that resemble stroke symptoms. This phenomenon is known as Todd’s paralysis, or postictal paralysis. It involves temporary weakness, numbness, or paralysis, typically on one side of the body, and can affect speech and vision.
Todd’s paralysis is a post-seizure effect, not a true stroke. It usually resolves within minutes to hours, though it can rarely last up to 36 hours. Distinguishing it from a stroke is important due to different medical management.
How Seizures Can Lead to Stroke
While rare, a severe or prolonged seizure can lead to a stroke or stroke-like brain injury. This is primarily observed in status epilepticus, defined as a seizure lasting over 5 minutes, or multiple seizures without full recovery. Sustained seizure activity places a high metabolic demand on the brain.
The brain’s increased need for oxygen and glucose during a prolonged seizure can outstrip supply, leading to anoxic-ischemic brain injury. This involves a lack of oxygen (anoxia) and reduced blood flow (ischemia), causing brain cell death similar to a stroke. In rare instances, severe seizures might also trigger cardiac arrhythmias that can lead to blood clot formation. If these clots travel to the brain, they can cause an embolic stroke.
How Strokes Can Cause Seizures
The reverse relationship, where a stroke causes seizures, is more common than seizures causing strokes. Brain damage from a stroke, whether ischemic (due to a clot) or hemorrhagic (due to bleeding), can disrupt the normal electrical activity of brain cells, leading to seizures.
Seizures within the first week after a stroke are termed acute symptomatic seizures. If recurrent, unprovoked seizures develop months or years after a stroke, it is diagnosed as post-stroke epilepsy. This delayed onset is often due to scar tissue formation or persistent brain damage, which alters neuronal networks and increases neuronal excitability. Post-stroke epilepsy is a significant cause of newly diagnosed epilepsy in adults, especially those over 60.
Key Differences Between Seizure and Stroke Symptoms
Recognizing seizure versus stroke symptoms is important for seeking appropriate medical attention. Both are medical emergencies, and prompt action is necessary. Seizure symptoms often include short-lived confusion, staring spells, uncontrollable jerking movements of the limbs, or a temporary loss of consciousness or awareness. Other signs can involve unusual sensations, altered emotions, or repetitive behaviors like lip smacking.
Stroke symptoms appear suddenly and can be remembered using the FAST mnemonic. F stands for face drooping. A is for arm weakness, often with one arm drifting downward when both are raised. S signifies speech difficulty, such as slurred words or trouble understanding speech. T emphasizes time to call emergency services.
Additional stroke symptoms include sudden numbness or weakness on one side of the body, sudden trouble seeing, or a sudden, severe headache. If any of these symptoms appear suddenly, immediate medical attention is necessary.