Epilepsy (54)
The facts
The name epilepsy comes from the Greek for "to be seized." Sudden, spontaneous seizure is the hallmark of this illness. It may involve falling to the ground and twitching spasmodically, but not always.
As the brain goes about its daily functions, millions of electrical and chemical signals pass from its nerve cells out to the body. These electrochemical messages are necessary for almost everything we do and feel.
Seizures are a sudden and abnormally high discharge of electrical activity among large numbers of nerve cells in the brain. This can result in involuntary and unusually large signals being sent to the muscles.
Epilepsy is one of the most common disorders of the central nervous system, affecting approximately 300,000 people in Canada. About a quarter of people with epilepsy in Canada will be diagnosed before the age of 10, and another third by the age of 19. The diagnosis of epilepsy is only made if there have been at least 2 episodes of unprovoked seizures on different days, or 1 episode of unprovoked seizure with a high chance of having another in the next 10 years. Having an "unprovoked" seizure means that there is no apparent trigger.
Causes
Epilepsy that first appears in adulthood is often due to some localized damage such as poor blood flow to the brain (including from a stroke), a brain tumour, or a previous head injury. Epilepsy in children can sometimes be brought on by meningitis during infancy or by abnormalities of brain development, but it is often inherited.
We know epilepsy can be passed on genetically, but we don't really understand what's different in the brain of a person with an inherited form of epilepsy. We also don't fully understand what happens to the brain during a seizure. Many people find that particular events tend to trigger seizures. These include:
- cocaine and some other drugs
- alcohol withdrawal
- exposure to flashing or strobe lights
- fever
- hormonal changes
- hyperventilation
- insufficient sleep
- intense exercise
- loud music
- skipping meals or poor nutrition
- starting or abruptly stopping some medications
- strong emotions
Catamenial epilepsy refers to seizures that are timed to the menstrual cycle. These seizures occur most during ovulation or just before menstruation. Seizures are apparently provoked by estrogen and prevented by progesterone. This explains why seizures begin around puberty for some people who menstruate, when estrogen dominates, and may improve after menopause.
Symptoms and Complications
Before a seizure, many people experience a warning sign called an aura, which may involve a particular smell, feeling, or visual effect. Most seizures will last no more than 1 to 2 minutes. After a seizure, a person may be confused, tired, or sleepy, may experience muscle aches or soreness, and may not remember what happened.
Many people believe that someone having an epileptic seizure is in danger of swallowing their tongue and choking. In reality, this almost never happens. If you try to prop the mouth open of someone who is experiencing a seizure, you can damage their teeth (or lose a finger). If the person is standing, you should usually do nothing; if they are unconscious, roll them on their side with something soft under their head and loosen the top button of their shirt.
An exception is in status epilepticus, when a seizure either keeps going for more than 5 minutes or recurs many times in a short period. It may be provoked after abruptly stopping antiseizure medication. You should call an ambulance if this happens.
Different types of seizures
Epileptic seizures are classified according to their particular characteristics. Classification takes into account where the seizure starts, the person's awareness, and other features of the seizure.
The seizure may be classified based on where it begins in the brain. For example, focal seizures start in one specific area, while generalized seizures can start on both sides of the brain.
The person's awareness during the seizure can also be used to describe and classify the seizure. People may be aware, meaning they don't lose consciousness or have impaired awareness. Other features used to classified seizures include the presence of movements during the seizure.
Epilepsy has a number of sexual and reproductive complications that we don't fully understand. Many epileptic people suffer from erectile dysfunction, dry vagina, painful contractions during sex, or low libido.
About 5% of babies born to people with epilepsy have a birth defect. This compares to about a 2% to 3% chance in the rest of the population. It's known that antiepileptic medications are responsible for at least some of the extra birth defects. The defects can be minor or corrected by surgery (malformed fingers, cleft lip, or palate), but occasionally more serious problems such as spina bifida can occur.
Making the Diagnosis
If you think you or your child may have had a seizure, see your doctor. You may be asked about your history of seizures, how long they last, when they occur, and how you feel afterwards. Family history may be relevant.
The primary test for epilepsy is the electroencephalogram (EEG). Wires are taped to the head and electrical activity is measured. It's completely painless and can even be performed while the person is asleep.
Computed tomography (CT) scans, positron emission tomography (PET), and magnetic resonance imaging (MRI) create detailed images of the brain. These are essential to check for trauma, tumours, abscesses, and infections such as meningitis that can cause epilepsy. Your doctor may draw your blood for electrolyte levels or other tests.
Treatment and Prevention
Anticonvulsant medications will eliminate or reduce seizures in most people. These medications will likely only be started after a second seizure occurs. There are several types, and not all of them work in every case. Examples of anticonvulsants include carbamazepine, lamotrigine, phenytoin, topiramate, and valproic acid. A doctor may need to try a few before finding the right one for a given person.
Unfortunately, many anticonvulsants can have side effects. Some can make a person mentally sluggish. Some can provoke facial hair growth and even blunt facial features. In children, they may cause learning or behaviour issues. They can also reduce the effectiveness of the oral contraceptive pill and cause birth defects.
If a person hasn't had a seizure while on medication for a long time (e.g. years), their doctor may discuss the possibility of slowly stopping the medication. Epilepsy is considered resolved if a person hasn't had a seizure in at least 10 years and has not used antiseizure medication for at least 5 of those years.
Epilepsy originating from a damaged part of the brain may require surgery when medications are not enough. This can sometimes cure the problem.
An implanted pacemaker-type device that stimulates the vagus nerve in the neck at regular intervals can sometimes improve seizures. A person wearing this device who feels a seizure coming can sometimes stop it by waving a small magnet over the implant to turn the stimulator on.
Anyone who is sexually active and could become pregnant, including those who have epilepsy, should talk to their doctor about folic acid supplements that reduce the risk of birth defects. There are also treatments for the various sexual problems that may accompany epilepsy.
Exercise is generally beneficial to those with epilepsy, and people rarely have seizures during exercise. People with epilepsy should take some common-sense precautions to avoid injury, such as avoiding swimming or bathing unsupervised, operating heavy machinery, or climbing ladders. Although some precautions are necessary, parents should try not to be overprotective. People with epilepsy can lead full, happy, and productive lives.
