Understanding Seizures After Stroke: Causes, Statistics, & Treatment

Seizures after a stroke occur because of changes in electrical activity within the brain. However, just because you’ve had a stroke does not mean you’ll experience a seizure. Many factors, including the severity and location of a stroke, can influence one’s likelihood of having a seizure.

To help you understand seizures after stroke, this article will discuss:

• What causes seizures after stroke?
• Are seizures common after a stroke?
• When do most seizures occur after a stroke?
• Types of post-stroke seizures
• Will a single seizure lead to post-stroke epilepsy?
• Can post-stroke epilepsy be treated?
• What to do when someone is having a seizure

What Causes Seizures After Stroke?

To understand the link between seizures and stroke, let’s discuss the definition of each.

A stroke is a neurological injury caused by either a blocked or ruptured artery in the brain. When a stroke occurs, an area of the brain is deprived of oxygen-rich blood, which can lead to tissue damage and other changes in the brain.

A seizure is caused by sudden disorganized electrical activity in the brain. When a stroke leaves behind scar tissue in the brain, it can disrupt the flow of electrical activity between nerve cells and cause a seizure.

Outwardly, seizures can look a variety of ways. Signs of a seizure occurring include changes in consciousness/awareness, cognitive or emotional changes (like confusion or anxiety), staring, and involuntary jerky movements of the arms and legs.

Other changes that occur in the brain following a stroke may make the brain more susceptible to seizures, including:

• Decreased blood flow
• Low cerebral metabolic rate for oxygen
• Increased blood-brain barrier permeability

While a stroke increases one’s risk of having a seizure, not all strokes are equal. The following section will discuss why some strokes are more likely to cause a seizure than others.

Are Seizures Common After a Stroke?

A recent meta-analysis of 102,008 stroke survivors suggests that about 7% of individuals experience seizures after stroke.  Therefore, it’s essential to understand the various factors that may contribute to increased seizure risk.

Some risk factors for post-stroke seizures include:

• Type of stroke. Seizures are more common following a hemorrhagic stroke (a stroke caused by a burst artery) than an ischemic stroke (a stroke caused by a blocked artery).
• Severity of stroke. The more severe the stroke, the greater the likelihood of having a seizure.
• Location of stroke. Seizures are more likely to occur when the stroke involves multiple lobes of the brain rather than a single location. Additionally, individuals who’ve had a stroke in the cerebral cortex are at greater risk for seizures.
• Age. This population-based cohort observed that seizures occurred within 24 hours of the stroke in 58% of children. Stroke is also the most common cause of seizures in the elderly. This supports the generalization that seizures are most common in children and individuals over the age of 65.

Additionally, seizures after stroke may not be related to stroke at all. For example, some individuals are genetically predisposed to seizures.

Up next, we’ll address when a seizure is most likely to occur after a stroke.

When Do Most Seizures Occur After Stroke?

Generally, a seizure is most likely to occur within the first 24 hours after the onset of stroke.  However, it is also common for seizures to occur within the first few weeks after stroke.

Every stroke is different, so seizure occurrence can vary greatly from person to person. For example, some of the stroke survivors in our support group have experienced their first seizure years after their stroke. This would be considered a very-late-onset seizure.

Often, there are two peaks in seizure occurrence after stroke. The first usually occurs within the first day while the second occurs sometime between 6-12 months.

The timing and type of seizure an individual experiences post-stroke has significant implications in regards to the occurrence of additional seizures. The following section will discuss how post-stroke seizures are classified and what they entail.

Types Of Post-Stroke Seizures

Seizures after stroke can be classified into early-onset and late-onset seizures. They are primarily differentiated by their underlying cause and their potential to cause additional seizures.

Generally, a seizure that occurs within the first week or two after a stroke is considered an early-onset seizure. Early-onset seizures are often provoked seizures, meaning that they usually occur immediately after a stroke but are caused by something else, such as a severe infection, high fever, or kidney failure.

In contrast, late-onset seizures occur at least 1-2 weeks after stroke. This type of post-stroke seizure is generally considered unprovoked, meaning that it is not caused by anything external, such as an infection. Unprovoked seizures imply more than a 60% risk of seizure recurrence.

Multiple, unprovoked seizures are the main criteria for a diagnosis of post-stroke epilepsy. Up next, we’ll discuss how seizures after stroke may develop into post-stroke epilepsy.  

Will a Seizure After Stroke Lead to Post-Stroke Epilepsy?

It’s reported that strokes account for about 11% of all adult epilepsy cases and 45% of epilepsy cases in individuals over 60 years of age.

Post-stroke epilepsy is a neurological disorder characterized by recurrent seizures that are not associated with a specific cause.

Having a single seizure does not necessarily mean that you will develop post-stroke epilepsy. However, if someone has two or more unprovoked seizures after a stroke, they are likely to be diagnosed with post-stroke epilepsy.

If you experience recurring seizures after stroke, be sure to seek emergency medical attention for an official diagnosis of post-stroke epilepsy.

Can Post-Stroke Epilepsy Be Treated?

Generally, treatment for post-stroke epilepsy consists of anti-epileptic drugs (AEDs, also called anticonvulsants), vagus nerve stimulation, or surgery.

There are several AEDs that can help reduce seizure frequency and severity and get your post-stroke epilepsy under control. They work by altering chemicals in the brain to reduce the excessive electrical activity that causes seizures to occur. However, they may not be ideal for all individuals as they have various side effects, including feelings of sedation.

Seizures after stroke may also be treated with the help of a vagus nerve stimulator. It uses electrical impulses to stimulate the nerves and prevent seizures.

If AEDs or vagus nerve stimulation prove ineffective, a surgical intervention called thermal ablation may help. Thermal ablation uses laser technology to remove the hyperactive brain cells that cause seizures to occur.   

Whichever treatment you choose, it’s always a good idea to set up a Seizure Response Plan with your family and friends. Being prepared with a response plan will help others care for you effectively if you have another seizure. The following section will provide more tips for this.

What To Do When Someone Is Having a Seizure

Watching someone experience a seizure can be a frightening experience. Individuals may suddenly become unresponsive, have uncontrollable body movements, and irregular eye movements. Therefore, knowing how to properly help someone who is having a seizure after stroke is critical for their health and safety.

If you are a stroke survivor, be sure to share this information with your friends and family so that they can be prepared to help you if a seizure occurs.

• Get them to the ground safely. If the person is on a bed or chair, move them to the floor gently. This will prevent them from falling and acquiring a serious injury.
• DO NOT hold the person down. When someone is having a seizure, stopping their movement will not stop the seizure. The seizure is happening in their brain, not their body. Holding them still will only hurt them and possibly yourself as well.
• Get them into a recovery position. Follow the steps from the Epilepsy Society to safely roll the person to their side and get them into a “recovery position.”
• Move nearby objects away. Since a person cannot control their body during a seizure, they are unaware of their environment and cannot avoid sharp objects around them. Keep them safe by moving anything dangerous away.
• DO NOT put anything in the person’s mouth. Because individuals cannot control their jaw movements during a seizure, putting something in their mouth is a major choking hazard and can cause serious damage to their mouth.
• Time the seizure. If a seizure lasts more than 5 minutes, call 911 immediately.
• Offer reassurance. After a seizure ends, the person is likely to be confused, anxious, and possibly embarrassed. Comfort them and let them know everything will be okay.

When to Call for Emergency Help

While seizures normally resolve on their own within 30 seconds to 2 minutes, it’s also important to know when a seizure requires emergency medical attention.

According to epilepsy.com, you should call for emergency help if the person…

• …has a seizure that lasts for longer than 5 minutes
• …experiences multiple seizures back-to-back
• …appears to be choking or has trouble breathing
• …is injured during the seizure
• …asks for medical help
• …is having a seizure for the first time

Seizures After Stroke: Key Points

Changes in the brain after a stroke (as well as the type, severity, and location of the stroke) can increase one’s risk of having a seizure.

Depending on how long after a stroke your seizure occurs, you may be at risk of having recurring seizures and developing post-stroke epilepsy. Fortunately, anti-epileptic drugs, vagus nerve stimulation, and surgery can help effectively treat epilepsy after stroke.

We hope this article helped you understand the implications of seizures after stroke and what to do if one occurs. It’s important for everyone to be knowledgeable about seizure management – so be sure to share this vital information with your loved ones!

featured images: iStock/LittleBee80/vadimguzhva/PIKSEL