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Reviewed by Dr Anthony Marson, lecturer in neurology, University of Liverpool
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What is epilepsy?
Epilepsy is a condition in which people have epileptic attacks
(also known as seizures). It is one of the more common neurological conditions,
affecting 0.5-1 per cent of the population. Epilepsy is not a single condition,
but a group of conditions with differing causes, treatments and
prognoses.
Not all seizures are due to epilepsy. For example, drugs
prescribed by doctors for other conditions - as well as substances such as
alcohol - can sometimes cause seizures.
At present, most doctors would not diagnose a patient as
epileptic if they had only suffered a single seizure. This is because epilepsy
is defined as a condition in which patients have recurrent
seizures.
The brain is made up of a vast number of nerve cells (neurones)
which communicate with each other through electrical signals. The interplay
between these neurones has to be carefully regulated for the brain to function
properly.
Epileptic attacks
happen when an abnormal electrical discharge occurs in the brain, disturbing
its normal function. The type of seizure depends upon where this takes place,
and how much of the brain is affected. During an attack, these discharges may
cause:
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twitching of the muscles
-
abnormal sensations (eg tingling on one side of the body or
awareness of a strange taste or smell)
-
emotional symptoms such as fear or 'deja
vu'
-
loss of consciousness.
Epileptic attacks are usually brief, lasting from seconds to a
few minutes. Once the attack is over, the normal electrical activity of the
brain resumes.
Epilepsy can start at any age, although it tends to first occur
in children and the elderly.
What can cause epilepsy?
Epilepsy can be caused by a wide variety of conditions that
affect the brain. In over half of those with epilepsy, no structural
abnormality in the brain can be found. For a large proportion of these people
the cause is probably genetic (see idiopathic generalised epilepsies). This is
particularly the case when epilepsy starts in children and
teenagers.
A structural cause is most likely to be found when epileptic
attacks have a focal onset (meaning that they affect a particular area of the
brain), which is why it is important to have a brain scan if a focal epilepsy
is suspected.
Possible
causes of epilepsy
include:
-
abnormalities in the development of the brain (congenital
abnormalities)
-
lack of oxygen during birth
-
infections (meningitis or
encephalitis)
-
brain tumours
-
cerebral thrombosis or haemorrhage (stroke).
What are the prospects for people with epilepsy?
Fortunately, seizures will go into remission for 70-80 per cent
of patients diagnosed as epileptic. However, the outcome of the condition is
very much dependent upon the type of epilepsy and what causes it.
How does the doctor make a diagnosis?
Epilepsy is a clinical diagnosis. In other words, the diagnosis
is not based upon the results of tests, but upon an accurate description of the
attacks. As patients are often unconscious or unaware during seizures, it is
extremely important for the doctor to get an eye-witness description of attacks
from another person. The doctor will need to differentiate seizures from other
conditions such as
fainting fits or
heart problems. Making a correct diagnosis can be difficult, and patients need
to see a specialist with sufficient expertise, such as a neurologist. If a
diagnosis of epilepsy is made, the following two tests are likely to take
place:
-
An EEG (electroencephalogram): it is commonly believed that
this is a diagnostic test for epilepsy. This is not true, as the EEG cannot
tell us whether a patient has epilepsy. It can, however, help us to work out
what type of epilepsy the patient has, which in turn will guide the choice of
treatment and prognosis.
-
A
CT scan or
MRI scan may be
carried out, especially if the patient is thought to have a focal epilepsy.
These tests are used to look for brain abnormalities that may be causing the
epilepsy.
You can suffer from epilepsy even if both the scan and the EEG
are normal.
If there is any uncertainty about the diagnosis, it may be
helpful to have a prolonged EEG. This sometimes takes place over a number of
days using video recording equipment to record any attacks.
Treatment
Epilepsy is usually treated with
medication prescribed
by a specialist. In some cases, it can be treated surgically.
Epilepsy and pregnancy
The great majority of women with epilepsy go through pregnancy
without difficulty. However, it is best to see your doctor before you get
pregnant, particularly if you are taking tablets for your epilepsy.
What should you do if someone has a seizure?
If a person is having an epileptic seizure:
-
try to remove any objects on which the person could hurt
themselves.
-
try to put the patient into the recovery position (lying on
their side with their airway clear).
-
never put anything in the person's mouth during an
attack.
-
stay with the person until they regain consciousness, then try
to calm them.
-
if the fit lasts for more than 10 minutes an ambulance should
be called immediately. Otherwise, it is usually not necessary to seek medical
attention after a seizure.
Lifestyle restrictions
It is important for people with epilepsy to try to get over any
fear of seizures and live their lives as normally as possible. However, there
are a number of restrictions such as those outlined below.
-
To hold a civilian driving licence in the UK you need to have
been seizure-free for 12 months, or only had seizures at night while
asleep.
-
Activities such as climbing and diving are best avoided if you
are still having seizures.
-
If you decide to go swimming it is best to go with a friend who
can keep an eye on you, and help out if necessary. Inform the lifeguard when
swimming in a public pool.
-
Flickering lights, such as strobe lights in nightclubs, can
trigger seizures in some people. If this is the case, clubs with strobes are
best avoided. It is also sensible to avoid playing computer games for long
periods of time as the flickering screen has been associated with seizures in
some susceptible people with epilepsy.
-
Some people's seizures can be brought on by lack of sleep,
or by drinking alcohol the night before. This calls for a more moderate
lifestyle, which can be particularly difficult for teenagers for whom this is
more commonly a problem.
Rigid guidelines are impossible as each person's epilepsy
is different. For example, it makes a big difference whether the fits are
unpredictable or whether they always occur at the same time.
Always discuss your own particular circumstances with your
specialist.
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Based on a text by Dr Per Rochat and Dr Jørgen Alving, consultant
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Last updated 02.03.2005
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