Details such as whether there was any warning, what the person was doing before the attack, what happened during the attack and how long it lasted can all provide useful information. This information needs to be obtained from both the person having the episode and a witness to the events.
There are a number of tests that may also help to confirm a diagnosis. Blood tests are often carried out to exclude a metabolic cause for the attacks; an electro-cardiogram (ECG) may also be performed to look for problems with the heart that may have caused the episodes. An electro-encephalogram (EEG), that records the electrical activity within the brain, is carried out to look for patterns characteristic of epilepsy. However a negative EEG does not exclude a diagnosis of epilepsy.
A magnetic resonance imaging (MRI) brain scan may also be carried out, this is not a diagnostic test but instead looks at the structure of the brain to see if there is a structural cause for the condition. If a MRI scan cannot be carried out, an X-Ray CT scan may be performed, which give lower definition images of the brain. Epilepsy sometimes arises as a result of a structural abnormality in the brain. This may have been present since birth or may have occurred later in life. There are a number of factors that may be involved, including head injury, brain infection, tumours or stroke. In many cases, however, no cause of epilepsy can be found, and it is believed that genetic factors play a role
.
The most common underlying causes of epilepsy vary with age; for example stroke is a frequent cause of epilepsy in people developing the condition over the age of 65, whereas in children other causes such as genetic factors and brain malformations are more common.
It is important to remember that the tests alone do not make a diagnosis of epilepsy; this remains a clinical decision based on what has happened to the person.
Q. A significant number of people are misdiagnosed with epilepsy every year. Why is this and what telltale signs should raise suspicion?
A. There are a number of events which can look like epileptic seizures but which have a different cause. They may be due to cardiac, metabolic, psychological or other factors. Sometimes these episodes are confused with epilepsy. It is important that people with possible epilepsy are investigated carefully and other possible causes ruled out. If a person has been diagnosed with epilepsy but the seizures have not been controlled with anti-epileptic medication, it is helpful for the diagnosis to be reviewed by a neurologist who specialises in epilepsy.
Q. What's the long-term outlook for someone with epilepsy? There's obviously much individual variation but, as a rough rule of thumb, does the condition become easier to manage or more difficult to manage with time, and do seizures cause any long term brain damage?
A. Epilepsy is a very individual condition and it is often not possible to predict its course. Some people's seizures are quickly brought under complete control with anti-epileptic medication. In others it may take more time to try different drugs or combinations of drugs in order to find what helps most. Overall up to 75% of people with epilepsy will be able to gain full control of their seizures with medication. Brain surgery may be an option for some people whose seizures cannot be controlled with medication, however many factors are involved and surgery will only be suitable for some people. In some specific childhood syndromes, the seizures will often stop in adolescence.
Prolonged seizures, particularly those that are convulsive, can cause some damage and therefore prompt medical treatment is important if a convulsive seizure is continuing for longer than 5 minutes. Repeated seizures in which there is loss of awareness for some minutes may cause damage. It is thought, at present, that seizures that are very brief or which do not cause loss of awareness do not cause damage to the brain.
Q. People often talk about trigger factors - things that trigger seizures in some people. What are the most common ones and could you briefly explain how they are linked to epilepsy?
A. As epilepsy is such an individual condition, different people are affected by different triggers, and many people are unable to identify any specific trigger for their seizures. However for a number of people, sleep deprivation or stress may bring about a seizure. Drinking a large amount of alcohol may trigger a seizure in the 'hangover' period. About 3-5% of people with epilepsy are photosensitive, meaning that their seizures are triggered by flashing or flickering lights or certain geometric patterns. They are usually sensitive to a particular frequency of flashes; computer monitors tend to flash at a frequency that is unlikely to cause problems. Photosensitive epilepsy can be diagnosed in an EEG and can often be well controlled with anti-epileptic medication.
Q. What are the long-term side effects of the most commonly used forms of medication for epilepsy? And are the latest drugs better in this respect?
A. Anti-epileptic medication affects people in different ways. Some people do not experience any side effects, whereas others may experience some adverse effects. In some people who have taken anti-epileptic drugs for many years, there may be effects such as overgrowth of gums, hirsutism, acne, weight change or visual field defects. The newer drugs have not yet been used for long enough to determine all the possible long-term side effects.
Q. If someone has been very well controlled (i.e. seizure free) at what stage would you consider stopping or reducing medication, and what is the likely outcome in a typical case?
A. Cessation of medication would not usually be contemplated until the person had been free of seizures for 2-3 years. The decision as to whether to withdraw medication is a complicated one. The risks of seizures recurring are different for each individual. The consequences and impact of a further seizure on their lifestyle also needs to be considered. If a person has been free of seizures for a few years, they may consider, in consultation with their doctor, gradually reducing and then stopping medication. However for some people, the risk of seizures recurring, with the consequent effects on driving licence, employment and other areas of life, is too great and they choose to continue taking medication. Medication should never be stopped abruptly or without advice from a doctor. Some specific syndromes such as juvenile myoclonic epilepsy are likely to require very long-term use of medication to prevent seizures recurring.
Q. Febrile convulsions are very common in young children and a lot of parents are concerned that their child will go on to have epilepsy in later life. Is there any evidence to support such concerns?
A. One child in 30 has a febrile convulsion. The great majority of children who have had febrile convulsions do not continue to have seizures or other problems. This applies even if there have been recurring febrile convulsions. However a small number of children do go on to develop epilepsy, and so overall there is a slightly increased risk that children who have had febrile convulsions will develop epilepsy.
Q. Are there any exciting developments in the pipeline that will lead to a significant improvement in the way we manage epilepsy?
A. New drugs are constantly under development by the pharmaceutical industry, with a view both to improving levels of control and reducing side effects. Many research programmes are also being undertaken by various teams throughout the world to learn more about the complex processes that cause epileptic seizures in order that they may be prevented.
The possibility is also being explored of administering the drugs directly to the part of brain that gives rise to the seizures, rather than giving the drug to the whole person.
Imaging of the brain with MRI has developed over the last 15 years is now recognised as an essential tool for diagnosing the causes of epilepsy. At present, conventional MRI scans can detect the cause of epilepsy in up to 80 per cent of patients whose seizures continue despite antiepileptic drug treatment. With the development of new MRI and other brain scanning techniques it is hoped that it will be possible to pin down the causes of more epilepsies, which will increase the potential for successful surgical treatment.
Q. Are there any alternative or complementary approaches that have been shown to be of any benefit?
A. Currently, the most effective treatment for epilepsy is anti-epileptic medication, and any other treatment should be seen as complementary, rather than an alternative, to conventional medication. As yet there is little evidence of the effectiveness of most complementary therapies, although those that encourage relaxation may help to reduce the frequency or severity of seizures.
Recent research has involved the use of aromatherapy to help control seizures; some people have learnt to associate the smell of an essential oil with a state of relaxation, helping to prevent seizures. Some essential oils should be avoided by people with epilepsy, and it is therefore important to consult a qualified practitioner.
There is a diet called the ketogenic diet, which can sometimes help to control seizures in some children with severe epilepsy. It has a high fat content and it is quite unpalatable; some people find it difficult to maintain in the long term. It is therefore only followed in consultation with the patient's doctor and a dietician.
About the Author
Professor John Duncan is a consultant neurologist specialising in epilepsy. He practices both at the National Hospital for Neurology and Neurosurgery at Queen Square, London, and at the National Society for Epilepsy in Chalfont St Peter, Buckinghamshire, where he is also Medical Director.
He was appointed Professor in Neurology at the Institute of Neurology (part of University College London) in 1998 and is now Head of the Department of Clinical and Experimental Epilepsy.
His particular current research interests include advanced techniques of imaging the brain using MRI (magnetic resonance imaging) and PET (positron emission tomography) scans, the genetic basis of the epilepsies and the surgical treatment of epilepsy.
Extramural appointments include Chairmanship of the International League Against Epilepsy Sub-Commission on Neuroimaging. He is also on the Editorial Board of several respected neurology journals.
We are indebited to the National Society for Epilepsy for their help in compiling this section.
