This article was last reviewed on
This article waslast modified on 17 February 2019.
What is it?

Epilepsy is a condition which causes seizures. Seizures happen when the normal electrical signals in the brain are over-run by uncontrolled and unorganised electrical interference. There are more than 40 different types of seizures from people becoming vacant or confused to odd rhythmic or repetitive movements, jerking or twitching of limbs, to convulsions that contract muscles throughout the entire body. Seizures can occur whilst people are awake or when sleeping and sometimes seizures begin with an aura. Auras are unusual feelings of sight, sound, smell, taste or touch that warn people of an on-coming seizure. For example, they may feel a cool breeze or a bright light and may include numbness or feeling sick. What happens during a seizure depends on which part of the brain is affected. Many people with epilepsy have similar symptoms with each seizure, but some may have a wide variety of symptoms. Rarely, less than 5% of people with epilepsy, the seizures are photosensitive meaning they can be triggered by flashing lights.

Most seizures last a few seconds to a few minutes. If a person’s consciousness is altered or lost, they may not remember what has happened. After a seizure some people feel normal, but others feel confused, may suffer from headaches, and can have weakness and tiredness for hours or even days afterwards. Most seizures do not have a lasting affect on the brain or body, but a loss of consciousness may lead to falls and injuries - especially if the affected person is driving, bathing, cooking, or doing other potentially dangerous activities. Seizures that last longer than 20 minutes are called status epilepticus. The longer a seizure lasts the more the risk of problems with breathing. Prolonged seizures, longer than 30 minutes, can increase the risk of permanent damage and can in some cases be fatal.

Not every seizure is epilepsy. Those that are due to other conditions such as a high fever in an infant, brain infections, pre-eclampsia or alcohol or drug withdrawal may not be called epilepsy. Some symptoms that look like a seizure are actually caused by problems in other parts of the body. Fainting, migraine headaches, narcolepsy, drug use, mental illness, heart conditions and many other medical problems can cause symptoms similar to a seizure.

Epilepsy is diagnosed when someone has two or more seizures, which are at least 24 hours apart, that cannot be explained by another diagnosis such as those mentioned previously. About 1 in 20 adults will experience a single seizure in their lifetime, but most will never have another one. There are about 600,000 people living with epilepsy in the UK affecting 1 in every 100 people according to leading epilepsy charities. While epilepsy can affect anyone, children (people < 20 years old) and adults over 65 are most likely to be affected. The majority of people with epilepsy will respond to treatment, but about 25-30% will continue to have seizures despite treatment. Any condition that affects the brain has the potential to cause epilepsy. This includes head injury, abnormal brain development, lack of oxygen during birth, brain tumours, strokes,  diseases of the heart and it’s blood supply, toxins such as lead poisoning, infections, diseases of the brain and nerves, and disorders of the body’s chemistry. Some forms of epilepsy run in families and are related to genetic problems. The cause of epilepsy in many cases is unknown and Doctors refer to this as idiopathic epilepsy.

Epileptic seizures can be described as either partial (focal) or generalized. Partial seizures originate from a single location in the brain, while generalized seizures involve both sides of the brain. A few seizures may start as partial seizures and then become generalised, and spread to involve the whole brain. About 60% of people with epilepsy have partial seizures. For more information about types of seizures, visit the Epilepsy Foundation website and read the article Seizures and Syndromes.


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About Epilepsy
  • Tests

    Laboratory and non-laboratory tests are used to diagnose and monitor epilepsy. They can help to determine what kind(s) of seizures the patient is having, identify causes such as toxins, infections, drug or alcohol withdrawal, fever (in a child), or diabetes that may be causing seizures, and to distinguish epilepsy from conditions such as fainting or a stroke that may cause some of the same symptoms.

    A medical history, input from the patient, and input from family members who have witnessed a patient’s seizures are important parts of the diagnostic process. The patient may remember a strange smell, an aura, and/or sensations that precede a seizure but may not remember what has happened during the seizure itself. Depending upon the signs and frequency of a person’s seizures, it may take some time to determine the proper diagnosis.

    Laboratory Tests
    Laboratory tests are usually used to monitor anti-epileptic drugs and to rule out other diseases such as diabetes, anaemia, infection, meningitis or encephalitis. Testing may include:

    Periodic therapeutic drug monitoring when a patient is taking a specific medication, such as Phenytoin.

    Other testing:

    Non-Laboratory Tests

    • Electroencephalogram (EEG) – a primary diagnostic tool for epilepsy; it is used to evaluate the brain’s electrical activity and identify changes in brain wave patterns.

    Imaging scans:

    • Computerised tomography (CT) – identify brain structure abnormalities and tumours
    • Magnetic resonance imaging (MRI) – also identify brain abnormalities
    • Positron emission tomography (PET) – radioactive material is used to look at active areas of the brain.
    • Single-photon emission computerized tomography (SPECT) – radioactive material is used to identify the region of the brain where seizures originate when it is not clear on other scans.


  • Treatments

    Epilepsy can be successfully treated in most people but may not be prevented or cured. The risk of epilepsy due to a head injury can be reduced by taking safety measures, such as by wearing a helmet while riding a bicycle or motorcycle and wearing a seat belt while in a car.

    In patients who have epilepsy, seizures can often be prevented or decreased in frequency by taking appropriate anti-epileptic drugs such as carbamazepine, phenytoin, lamotrigine, levetiracetam or valproate. The choice of drug depends on the patient and on the type of seizure. A person should work with their doctor to find the right medication(s) and dose.

    The number of seizures can also be decreased by avoiding seizure triggers such as being tired from lack of sleep, becoming very stressed, alcohol consumption, and use of illicit drugs such as cocaine. Treating underlying conditions can also reduce the frequency of seizures.

    Some types of seizures can respond to brain surgery or vagus nerve stimulation. Deep brain stimulation may be an alternative to brain surgery but is still being researched. For some types of epilepsy a ketogenic diet is the cure whilst it may help some others. A ketogenic diet is best undertaken with support from epilepsy and dietetics experts.