Some stroke survivors can experience seizures. These are most likely to happen within the first few days following a stroke, but your first seizure could occur two or more years later.
Some people will have repeated seizures, and be diagnosed with epilepsy. But if you have a seizure after a stroke, it doesn’t necessarily mean you have epilepsy or will go on to develop it. Overall, your risk of having a seizure reduces over time after a stroke.
What is a seizure?
Cells in the brain send electrical signals to one another. The electrical signals pass along your nerves to all parts of the body. A sudden abnormal burst of electrical activity in the brain can lead to the signals to the nerves being disrupted, causing a seizure. This electrical disturbance can happen because of stroke damage in the brain.
A seizure can affect you in many different ways such as changes to vision, smell and taste, loss of consciousness and jerking movements. For more information see Types of seizure.
Seizures after stroke
You’re more likely to have a seizure if you had a haemorrhagic stroke (bleed on the brain). Seizures can also be more likely if you had a severe stroke, or a stroke in the cerebral cortex, the large outer layer of the brain where vital functions like movement, thinking, vision and emotion take place.
Seizures and epilepsy
Epilepsy is a condition which causes repeated seizures. People can develop epilepsy at any age, and in around half of all cases, there is no obvious reason for it to happen. Epilepsy can be due to a brain injury or other condition such as stroke, an infection or a growth in the brain. Overall, stroke is the cause in around 10% of adults newly diagnosed with epilepsy.
Types of seizure
Seizures can vary, ranging from tingling sensations or ‘going blank’ for a few seconds, to shaking and losing consciousness. Some people have only one type of seizure, and some have more than one type.
There are three main types of seizure:
Focal onset seizures
Some seizures only occur in part of the brain, known as focal onset seizures. There are two kinds of focal seizures, motor (physical signs like moving arms or falling), and non-motor (affects senses, awareness and emotions).
Generalised onset seizures
A generalised seizure involves the whole brain and affects the whole body. Motor (physical) signs can include losing consciousness and muscle spasms. A non-motor seizure could be a brief period of absence or blankness, where the person stops moving and looks as if they are staring into space.
Unknown onset seizure
If it’s not possible to tell where the seizure began in the brain, doctors may describe your seizure as motor or non-motor. Motor (physical) signs might include losing consciousness and having jerking movements, and non-motor signs can affect emotions and sensations.
How is epilepsy diagnosed?
A seizure may take place very soon after the stroke. If you are in hospital at the time you should have help from the medical team on the ward. If you have already left hospital and think you have had a seizure, contact your GP.
You should be referred to see a specialist within two weeks. The specialist is usually a neurologist, an expert in the brain and nervous system. While you're waiting for the appointment, it's best to avoid any activities that could put you, or others, in danger if you have another seizure. For example, don’t go swimming, and have showers rather than a bath. You must not drive if you have had a seizure.
You may not be able to remember the seizure, so if someone else witnessed it, they could visit the specialist with you. Or they could send a written account or, if possible, a video of the seizure. It may help to keep a seizure diary recording the date and time of your seizures, what happened and any possible triggers such as stress or drinking alcohol.
The specialist will ask you questions about what happened. This may be enough to make a diagnosis. Further tests may be needed, particularly if the seizure did not involve convulsions. These tests don’t prove whether you have epilepsy, but they can give information about the possible cause, and the type of epilepsy you have.
Tests used in diagnosing epilepsy
A common test for epilepsy is an EEG. It is a painless test which involves placing electrodes on your scalp. These measure electrical activity in your brain, and can identify any unusual patterns. The test only shows what is happening in your brain at that time, so a normal EEG doesn’t necessarily mean that you do not have epilepsy. An EEG usually takes about one hour and can be done at an outpatient clinic.
Magnetic resonance imaging (MRI)
An MRI scan can find problems inside the brain which might cause epilepsy, including the damage left by a stroke.
Treatments for epilepsy
Anti-epileptic drugs (AEDs)
Medication can usually reduce seizures and allow you to lead a normal life. The treatment you have will depend on:
- What type of seizures you have.
- Your age and sex.
- How frequent your attacks are.
- Other effects of your stroke, like swallowing problems.
- Other medication you are taking.
Anti-epileptic drugs or AEDs usually work by changing the levels of chemicals in the brain. In some cases the normal activity of the brain may also be affected, leading to drowsiness, dizziness, confusion and other side effects. Once your body is used to the medication, these side effects may go away. Your doctor might start you on a low dose and increase it gradually to reduce the chances of you having side effects. If they are severe or last a long time, your doctor may change the dose or try a different medication.
Everyone is different, and some people experience side effects from a particular medication even at a low dose. However, you can usually try a different type if this happens, as there are many safe and reliable AEDs available.
You might be given a single drug or a combination of two or more. The type you are given depends on the type of seizures, and any side-effects you have from a particular drug or combination.
If you have symptoms like feeling unsteady, having poor concentration or vomiting, your dose could be too high and you should contact your GP or specialist.
Surgery may be an option if anti-epileptic drugs do not help you, and if your epilepsy is due to a physical cause in your brain, such as scarring or stroke damage. Whether you can have surgery depends partly on where the problem lies inside your brain, and whether a surgeon can reach it safely. Having surgery in your brain can be very risky. You can work with your doctor to understand the risks and possible benefits to you before choosing to go ahead.
Vagus nerve stimulation therapy
A small electrical device is implanted in the neck and connects to the left vagus nerve. The device sends regular electric signals to the brain via the vagus nerve, which can help regulate electrical activity in the brain that causes epilepsy.
This treatment is used for children (and occasionally adults) who don’t respond to AEDs. It involves a high-fat, low carbohydrate diet. This changes the way the brain uses energy, which may reduce seizures. It should only be used with the help of a specialist doctor and dietician.
First aid for seizures
These tips can help you help someone who is unconscious and making jerking movements.
- Protect the person from injury by removing any harmful objects nearby and cushioning their head.
- Loosen any tight clothing from around their neck.
- Look for any identity card or jewellery that might give you advice on what to do.
- Do not attempt to restrain the person or bring them round.
- Do not move them, unless they are in danger.
- Do not put anything into their mouth.
- After the seizure has finished, turn them on their side to help them breathe more easily.
- Do not give them anything to eat or drink.
- Be calm and reassuring, stay with them until they have completely recovered.
- Make a note of how long the seizure lasted.
Call 999 if:
- One seizure follows another without the person recovering in between.
- The seizure continues for more than five minutes.
- The person is injured or seems to need urgent medical attention.
- You think it is the person’s first seizure.