A seizure is usually triggered by a burst of abnormal electrical activity in your brain. It can affect movements, emotions, behaviour and consciousness.

By Wallace Health I Medically reviewed by Adrian Roberts.
Page last reviewed: October 2018 I Next review due: October 2021

Summary

A seizure, which is sometimes known as a fit, can last from a few seconds to several minutes. Possible seizure symptoms, which can vary in severity, include:

  • Confusion, fear, anxiety
  • Loss of awareness and, in some cases, consciousness
  • Tingling sensations
  • Uncontrollable jerking movements or shaking

A seizure can happen to anyone at any age. One in 20 people have a seizure at some point in their life.

If you've had two or more seizures, you may have epilepsy — a condition affecting about one in every 100 people. Epilepsy is more likely to develop in childhood or over the age of 60. There are different types of epileptic seizures and you may have more than one type.

Although epilepsy can’t be cured, it can usually be managed. In most cases, seizures can be controlled with medication.

What causes a seizure?

Often, the exact reason for a seizure isn’t known, especially if it’s a one-off or if it occurs in young children.

Epilepsy is a common cause of seizures but a range of other health conditions that affect your body can consequently have an impact on your brain, resulting in a seizure. Other causes include: 

  • Brain trauma — perhaps as a result of a brain tumour, drug or alcohol misuse, fatigue, head injury, meningitis or a stroke 
  • Cancer
  • Fever or high temperature
  • Flickering lights
  • Imbalances in your electrolytes (salts and minerals that your body needs to function properly)
  • Low blood sugar (hypoglycaemia)

Your risk of a seizure is also increased if you: 

  • Are infected with COVID-19
  • Have family members with a history of epilepsy or other seizures
  • Take certain painkillers, antidepressants or smoking cessation medications

Not all seizures are caused by abnormal bursts of electrical activity in the brain. Dissociative seizures, which are also known as non-epileptic seizures, can be caused by a range of factors. Possible causes of dissociative seizures include: 

  • Anxiety and panic attacks
  • Diabetes 
  • Heart problems 

Dissociative seizures require diagnosis and treatment from a consultant.

Types of seizure

Seizures caused by abnormal brain activity can be divided into two groups, focal seizures and generalised seizures.

Focal seizures

These seizures are caused by abnormal brain activity in one area of your brain and may or may not involve a loss of consciousness. 

In cases where you do experience a change or loss of consciousness, you may stare into space, respond abnormally to your environment or perform repetitive movements, such as chewing, hand rubbing, swallowing or walking in circles.

In cases where you do not lose consciousness, you may experience a change in your emotions, senses (sight, smell, hearing, taste or touch) or ability to control your body movements eg involuntary jerking of a body part. You may also feel dizzy or tingly, or see flashing lights.

Generalised seizures 

These seizures are caused by abnormal activity across your entire brain; they include: 

Absence seizures

Formerly known as petit mal seizures, these seizures tend to affect children. They involve slipping into a trance-like state for up to 15 seconds with a loss of awareness and subtle repetitive body movements, such as eye blinking and lip-smacking. They can occur in clusters. 

Atonic seizures

Atonic seizures cause all of your muscles to suddenly relax. You may therefore lose your balance and collapse but as these seizures are very brief, you will usually be able to get straight back up after falling.

Complex partial seizure

Complex partial seizures cause you to lose awareness and have random, erratic body movements.

Clonic seizures

Clonic seizures cause repetitive or rhythmic jerking of your body parts, usually affecting your arms, face and neck. 

Myoclonic seizures

Myoclonic seizures cause the sudden and brief jerking or twitching of your arms and legs. 

Simple partial seizure (aura) 

You remain conscious but with a strange out-of-body experience which may include feelings of déjà vu.

Tonic seizures

Tonic seizures cause all of your muscles to suddenly stiffen. You may therefore lose your balance and collapse. 

Tonic-clonic seizures

Formerly known as grand mal seizures and often referred to as an epileptic fit, these seizures cause you to lose consciousness and collapse, with your body stiffening and legs and arms jerking. You may also bite your tongue and urinate. 

Talk to your doctor if you’re concerned about symptoms

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Seizures in your sleep

If you have epilepsy, you may experience asleep seizures, also called nocturnal seizures, which occur while you are sleeping, as you are falling asleep or as you are waking up. Asleep seizures are not limited to nighttime but can happen any time of day when you are sleeping. The seizures can be generalised or focal. 

Asleep seizures are particularly common if you have frontal lobe epilepsy, where seizures often occur when you are awake and when you are asleep, specifically during the first phase of sleep (non-rapid eye movement sleep) ie as soon as you fall asleep. 

Frontal lobe seizures often occur in clusters but are usually short-lived. Symptoms include: 

  • Loud cries or screams 
  • Sudden jerking movements
  • Unusual postures or movements of your arms or legs
  • Wandering around while asleep

Getting a diagnosis for seizures

Whether you’ve had one seizure or repeated seizures, see your GP as soon as possible. Other conditions, such as fainting, migraines and panic attacks, can cause symptoms similar to a seizure so your GP will ask about your seizure symptoms and medical history to rule out these conditions. 

They will also ask you when your seizure happened, what you were doing when it happened and how you felt during and after your seizure. If you’re unsure, take someone with you who witnessed what happened or bring a video recording of your seizure. 

Your GP may recommend a range of investigations to help determine the cause of your seizure and the likelihood of you having another seizure. These tests may include:

  • A neurological examination — this involves assessing your behaviour, body movements and mental ability; this will help determine if you have a problem with your brain or nervous system
  • An electroencephalogram (EEG) to record your brain’s electrical activity
  • Blood tests to check your overall health
  • Lumbar puncture — collection of fluid from your spine (cerebrospinal fluid) to check for an infection, which can cause seizures

They may also recommend imaging tests to look for any brain abnormalities or injuries. These imaging tests include:  

  • CT scan 
  • MRI scan
  • Positron emission tomography (PET) scan — a safe, low dose of a radioactive substance will be injected directly into a vein to help create images of your brain during your scan
  • Single-photon emission computerized tomography (SPECT) — a safe, low dose of a radioactive substance will be injected directly into a vein to help create a 3D map of blood flow in your brain during your seizure and then again 24 hours later; this is done while you are admitted in hospital to monitor your seizures
  • Subtraction ictal SPECT coregistered to MRI (SISCOM) scan — a type of SPECT scan that produces more detailed images of the blood flow in your brain; this is usually done alongside an overnight EEG recording while you are admitted in hospital to monitor your seizures

In some cases, your GP may refer you to a consultant for further assessment, diagnosis and treatment. Getting a diagnosis is often not possible until you have had more than one seizure.

If you have epilepsy, your doctor will provide you with advice and information about living with this condition.

Treatments for seizures

If you know what triggers your seizures, avoiding these triggers may be enough to prevent any future seizures. Common triggers include drinking alcohol, a lack of sleep and stress. 

If it isn't clear what is triggering your seizures, keep a seizure diary. Record when you have seizures and what you were doing when you had them to see if you notice any patterns ie potential triggers. 

For some people, seizures may go away over time. However, you may need to be treated for epilepsy for the rest of your life. Treatments include:  

Medication

Anti-epileptic drugs can usually prevent or reduce the severity and/or frequency of seizure symptoms. Your doctor will recommend treatment after considering your type of seizure, overall health, age and any pregnancy plans. You may need to try several different types of anti-epileptic drugs to find the one that works best for you as they often cause side effects.

It is important to take your medication every day as directed by your doctor to ensure that your epilepsy is well-controlled.

Lifestyle changes

Your doctor may recommend following a ketogenic diet to reduce the risk of seizures. This involves eating a diet low in carbohydrates and rich in fats and proteins.  

It is also important to sleep well and for long enough each night. Poor sleep or lack of sleep can trigger seizures. 

Brain or nerve stimulation

Vagus nerve stimulation

Your vagus nerve runs from your brain to your stomach. Stimulating this nerve can reduce the frequency of your seizures. Vagus nerve stimulation involves inserting a device under the skin of your chest that will send electrical signals to your brain via your vagus nerve. You may still need to take anti-epileptic drugs.

Responsive nerve stimulation

This involves implanting a device into your brain which detects and stops seizures by sending electrical signals. 

Deep brain stimulation

This involves implanting several devices into different areas of your brain and a machine similar to a pacemaker into your chest. The pacemaker-like device will send electrical signals to the devices in your brain to prevent or stop seizures. 

Surgery

Very rarely, your doctor may recommend surgery to remove a small part of your brain which is causing the seizures or surgery to implant a special device to control electrical impulses in the brain.

Regular reviews

Once you have been diagnosed and treated for epilepsy, it is important to attend regular reviews with your GP or epilepsy care team. Reviews should occur at least once a year or more if your epilepsy is not well-controlled. 

Alternative therapies

There is no clear evidence to show that alternative therapies, such as herbal remedies or aromatherapy, help prevent seizures. 

If you want to try a herbal remedy, speak to your GP first as some of the ingredients in herbal remedies can interfere with your anti-epilepsy medication — eg St John's Wort is known to affect the levels of anti-epilepsy medication in the blood and may stop it working properly. 

Strong-smelling aromatherapy treatments are not recommended as several, including hyssop, rosemary and sweet fennel, have been shown to trigger seizures in some people.

As stress can sometimes trigger epilepsy in some people, relaxation techniques may help, such as exercise, meditation and yoga.

How to stay safe if you have seizures

Seizures can put you and others at risk, depending on what you are doing at the time eg cooking, driving or swimming. If your seizures aren't well-controlled, you can take steps to reduce the risk of injury. 

At home

  • Cover any sharp edges or corners on furniture
  • Do not lock the bathroom door and have showers not baths
  • Install guards on your heaters and radiators to avoid falling directly onto them
  • Install smoke detectors — if you have a seizure when cooking, which causes you to lose awareness, your smoke detector will let you know that food is burning
  • When cooking, place pans on the back burners with handles turned away from the edge of the cooker

Driving

If you have had even one seizure, you must stop driving and tell the DVLA. Your driver's licence may be taken away until your seizures are well-controlled. When you can reapply for your driver's licence will depend on your type of seizure. If you had seizures that caused a loss of consciousness, you can't reapply until you have not had a seizure for at least one year. 

Sports and leisure

  • Avoid swimming or doing water sports on your own
  • If going to a gym, ask the staff which equipment is safe for you to use in case you have a seizure
  • Wear a helmet while cycling or horse riding

What to do if someone has a seizure

Someone with epilepsy may not need to go to the hospital every time they have a seizure. However, you should call 999 if: 

  • It is the first seizure someone has had
  • Someone’s had a seizure for over five minutes
  • They’ve failed to regain consciousness following a seizure or have had several seizures and failed to regain consciousness 
  • They’ve seriously injured themselves during the seizure

If someone is having a seizure only move them if they are in danger of hurting themselves eg if they are near a busy road or hot cooker. Check if they have a bracelet or card that tells people they have epilepsy. 

Make sure you do

  • Cushion their head if they are on the ground — if they are in a wheelchair, put the brakes on and leave any harness on; cushion their head but do not move them
  • Loosen any tight clothing around their neck to help them breathe
  • Place them into the recovery position after the seizure stops
  • Stay with them and calmly talk to them until they recover
  • Record what time the seizure started and how long it lasted

Make sure you do not

  • Give them anything to eat or drink until they've fully recovered

Frequently asked questions

Can a seizure kill?

Death from an epileptic seizure is very rare. It may occur due to serious injury during a seizure or, in extremely rare cases, due to sudden unexpected death in epilepsy (SUDEP) — there is just over one incidence of SUDEP for every 1,000 people with epilepsy each year.

What does a seizure look like?

Seizures look different according to the type of seizure. Some seizures cause the muscles to stiffen while others cause them to relax. Your body parts may jerk or shake, or you may be still.

How serious is a seizure?

Although most seizures don’t cause serious problems, if you have seizures, you will need treatment to help prevent them or reduce their frequency. This is because every seizure puts you at risk of injury during your seizure.

Are seizures painful?

Seizures are not usually painful — although you may injure yourself during a seizure and on recovering from your seizure be in pain from the injury.

How long can a seizure last?

A seizure can last from several seconds to several minutes. If a seizure lasts more than five minutes, someone should call 999. 

Can seizures be cured?

This depends on the type of seizures you have. Seizures can usually be well-controlled, but not cured, with medication. In some cases, brain stimulation with a medical device can prevent or reduce the frequency of seizures. In rare cases, where seizures are caused by abnormal activity in one specific brain area, surgery to remove this part of the brain can stop the seizures. 

What is the best treatment for seizures?

Seizures are most commonly treated with anti-epileptic drugs, which you will have to take every day as directed by your doctor. You may need to try several different types to find the one that works best for you as they often have side effects. If your seizures are not well-controlled by avoiding triggers and taking medication, your doctor may recommend other treatments, such as brain stimulation with a medical device or, in rare cases, surgery.

What is the first aid treatment for seizures?

If you notice someone is having a seizure, check if they have a bracelet or card that tells people they have epilepsy. Only move them if they are in danger of hurting themselves eg if they are near a busy road or hot cooker. Then cushion their head if they are on the ground, loosen any tight clothing around their neck to help them breathe, and record what time the seizure started and how long it lasts. Once the seizure is over, place them into the recovery position, stay with them and calmly talk to them until they recover. Do not give them anything to eat or drink until they've fully recovered and do not put anything in their mouth, including your fingers.

How do you stop a seizure permanently?

If you know what triggers your seizures, avoiding these triggers can prevent you from having further seizures. In some cases, seizures disappear by themselves over time. Medication and different types of brain stimulation by a medical device can both help prevent or reduce the frequency of seizures. In some rare cases, surgery is used to prevent or reduce the frequency of seizures.

What is the main cause of a seizure?

It isn't always possible to identify the exact cause of a seizure, especially in young children or if it is a one-off seizure. A common cause is epilepsy, a condition that causes abnormal brain activity. However, abnormal brain activity that leads to seizures can also be caused by brain trauma (eg brain tumour, drug or alcohol abuse, head injury, meningitis or stroke), cancer, fever or low blood sugar. Flickering lights and certain medications can also trigger seizures. Dissociative seizures are not caused by abnormal brain activity and may be triggered by anxiety and panic attacks, diabetes or heart problems.

How are seizures diagnosed?

Your doctor will ask you about your seizure symptoms, what you were doing when you had your seizure and how long it lasted, as well as your medical history and whether you have a family history of seizures. This will help rule out other conditions with similar symptoms, such as panic attacks or fainting. They will also perform a neurological examination to help determine if you have a problem with your brain or nervous system. They may recommend blood tests, an electroencephalogram to record your brain’s electrical activity or, if they suspect an infection, a lumbar puncture. There is also a range of imaging tests that can be performed to investigate any potential abnormal brain activity.

What are the first signs of a seizure?

Warning signs of a seizure vary depending on the type of seizure you have. However, common warning signs, some of which may also be part of the seizure itself, include: 

  • Confusion, daydreaming, forgetfulness and sleepiness
  • Experiencing unusual feelings, smells or tastes
  • Headaches
  • Out-of-body sensations
  • Tingling, numbness or feelings of electricity in part of your body

Can a doctor tell if you've had a seizure?

The speed at which you recover from a seizure varies from person to person and is also dependent on the type of seizure you’ve had. In some cases, recovery is very quick, within minutes, and you will not show any outward signs of having had a seizure that a doctor can detect by physically examining you. However, in some cases, recovery from a seizure may take several days. You may feel confused, sleepy, thirsty or tired, or have headaches — symptoms which your doctor will ask you about. 

How are seizures diagnosed in adults?

Seizures are diagnosed by your doctor assessing your symptoms and asking questions about what you were doing when you had your seizure and how long it lasted. If you have a video recording of your seizure, it is helpful to bring this along to your GP appointment. Your doctor will also perform a neurological examination to check your ability to move, behaviour and mental capacity — this will help determine if you have a problem with your brain or nervous system. 

They may recommend blood tests, an electroencephalogram to record your brain’s electrical activity or a lumbar puncture if they suspect an infection. You may also need to have a brain scan, which can be performed using different imaging methods, such as a CT scan, MRI scan, PET scan, SPECT scan or SISCOM scan.