Epilepsy

What is epilepsy?

Epilepsy is a condition in which a person has repeated seizures. A seizure is caused by abnormal electrical impulses between the nerve cells (neurones) of the brain. Anyone can have a seizure if the brain is exposed to a strong enough stimulus – one in every 20 people will have a single seizure at some time during their lives. However, in people with epilepsy, these seizures recur.

The type and effect of seizures can vary from person to person and for most, epilepsy will only affect them for a short period in their lives. For others however, the consequences can be more lasting. Up to 40,000 people in Ireland are estimated to have epilepsy.

What are the different types of epilepsy?

The type of epilepsy experienced depends on where in the brain the seizure takes place. There are two main categories: generalised seizures, in which the whole brain is affected and the person falls unconscious, and partial seizures, which affect a distinct part of the brain.

Types of generalised seizure include:

  • Tonic-clonic seizures: these were previously known as ‘grand mal’ and can be considered the most dramatic type of seizure. The person may cry out, fall to the ground and lose consciousness. The person may twitch and jerk their arms and limbs around.
  • Tonic seizures – the muscles will stiffen and the person may fall heavily to the floor. There is no jerking however.
  • Atonic seizures – muscle tone is suddenly lost, causing the person to flop and fall.
  • Clonic seizures – the muscles contract and relax causing repeated twitching and jerking.
  • Myoclonic seizures – the muscles jerk as if the person has had an electric shock.
  • Absence seizures – normally occurring in children, these occur suddenly and provoke a trance-like state, where the child fails to respond to anyone talking to them.

Partial seizures include:

  • Simple partial seizures – may affect motor neurones, causing movement of the limbs, head or neck; or sensory neurones, causing physical sensations such as tingling or unnatural warmth.
  • Complex partial seizures – produce impaired or altered consciousness – they may cause the person to become disorientated, smack their lips or wander about aimlessly.

What is status epilepticus?

If a seizure is prolonged, or if there is a series of seizures over a period of time during which the person does not regain consciousness, this is referred to as status epilepticus.

This is a medical emergency requiring immediate treatment. When a seizure is prolonged, there is always a danger of a complication, such as brain damage caused by a lack of oxygen.

People with different types of epilepsy can develop status epilepticus. Only a small percentage of people with epilepsy will develop status epilepticus, however it is more common among young children. Treatment consists of the person being given diazepam as quickly as possible.

What can I do if someone is having a seizure?

This depends on what type of seizure it is. You cannot prevent someone from having a seizure. However, you can protect someone who is having a convulsive seizure from injury by putting something soft under their head and removing anything nearby on which they may injure themselves.

If it is an absence seizure or a partial seizure where they remain conscious, you can simply wait for it to pass.

You only need to call for an ambulance if the seizure lasts longer than 5 minutes, if the person starts having repeated seizures or the person injures themselves. Find out more about what to do if someone has an epileptic seizure in the irishhealth.com first aid section.

What causes epilepsy?

In more than half of all cases of epilepsy, no cause can be found (this is known as idiopathic epilepsy). The seizures are caused by a lack of chemical substances in the brain that normally regulate electrical impulses. The person with idiopathic epilepsy is apparently healthy in every other respect and there is no underlying disease or damage causing them to have seizures.

In some cases a cause is found and there may be several reasons why epilepsy is triggered:

  • Damage to the brain with or without scarring as a result of injury to the head, infection of the brain (encephalitis) or brain linings (meningitis)
  • Malformation of the brain
  • Degeneration of the brain
  • Metabolic (biochemical) disorder as a result of low blood glucose, low calcium or drugs, particularly alcohol
  • Brain tumours
  • Blood clots and brain haemorrhages.
  • There may also be genetic factors, but for the majority of people, inheritance plays only a limited role.

What are seizure triggers?

Most people with epilepsy don’t have a single thing that triggers a seizure; however, they can occur if the person gets very tired, hungry or forgets their medication. Stress, alcohol and illegal drugs can also sometimes bring on a seizure, and about 3-5% of people with epilepsy are photosensitive (may have seizures in response to flickering lights).

How is epilepsy diagnosed?

Your GP will refer you to a specialist if they suspect you have epilepsy – usually a consultant neurologist or a consultant physician with a specialist interest in epilepsy.

The first appointment will generally consist of a discussion about symptoms. It can be useful to bring along a relative or friend who has seen you having a seizure. You will have the opportunity to explain in detail what has been happening and specifically what happened around the time of the seizure. A physical examination will also take place.

The diagnosis is usually based on what you and your relative or friend tell the doctor. There is no actual test for epilepsy. Blood tests may be carried out to rule out possible causes of the seizure. An Electroencephalogram (EEG) may also be carried out in hospital to help doctors identify what type of epilepsy you have. Some people may also have a CT or MRI brain scan, to help identify structural causes of the problem.

It is difficult to say how many seizures you must have before a diagnosis of epilepsy can be definitely made. A classical tonic-clonic seizure that included tongue biting and passing urine during the seizure and was observed by a reliable witness would probably lead to a diagnosis of epilepsy after one incident. However, in other situations diagnosis is more difficult and involves detailed history taking and brain investigations.

How is epilepsy treated?

While there is no cure for epilepsy, it can be controlled with a range of anti-epileptic drugs (AEDs), which act on the brain to prevent or reduce seizures. There are many different AEDs available and the choice of drug will depend on the type of epilepsy you have. Your doctor will normally start you on the smallest dose possible, and then the dosage will be adjusted if the drug is not effective. In certain cases where symptom control is proving difficult, more than one medicine may be prescribed.

Another treatment option is a technique called vagus nerve stimulation, in which an electronic stimulator is inserted under the skin of the chest wall or under the arm to deliver electrical stimulation to the brain, in order to reduce seizures. However, there is no way of knowing if the stimulator will work prior to insertion.

Surgery on the brain may also be considered in certain circumstances, e.g., if there is a specific structural problem causing the epilepsy or if drug treatment has proved unsuccessful. However, only a few people are suitable for surgery, and it is generally considered as a last resort.

What is the outlook?

For many people with epilepsy, treatment will stop seizures. However, the outcome of the condition is dependent on the type and cause of epilepsy. Some people who develop epilepsy as a child 'grow out' of it and experience no long-term effects.

Many people with epilepsy lead normal lives and have no symptoms between seizures. However, practical issues, such as driving restrictions, may have a significant impact on the day-to-day lives of people with epilepsy.

Brainwave, the Irish Epilepsy Association, works to improve the quality of life of people with epilepsy in Ireland. Contact Brainwave on Tel: 01-4557500, Email: info@epilepsy.ie, Website: www.epilepsy.ie

 

Visit the irishhealth.com Epilepsy Clinic for detailed information all about epilepsy.

 

Reviewed: November 29, 2006