Epilepsy

What is Epilepsy?
Epilepsy is a neurological condition, which affects the nervous system. Epilepsy is also known as a seizure disorder. It is usually diagnosed after a person has had at least two seizures that were not caused by some known medical condition like alcohol withdrawal or extremely low blood sugar. Sometimes, according to the International League Against Epilepsy, epilepsy can be diagnosed after one seizure, if a person has a condition that places them at high risk for having another.

The seizures in epilepsy may be related to a brain injury or a family tendency, but most of the time the cause is unknown. The word "epilepsy" does not indicate anything about the cause of the person's seizures, what type they are, or how severe they are.

Topic Editor: Carol Camfield, M.D. / Robert S. Fisher, M.D., Ph.D.

What Is a Seizure?
A seizure is a sudden surge of electrical activity in the brain that usually affects how a person feels or acts for a short time. Seizures are not a disease in themselves. Instead, they are a symptom of many different disorders that can affect the brain. Some seizures can hardly be noticed, while others are totally disabling.

The seizures in epilepsy may be related to a brain injury or a family tendency, but often the cause is completely unknown. The word "epilepsy" does not indicate anything about the cause or severity of the person's seizures.

If I have one seizure, does that mean I will get epilepsy?
About half of the people who have one seizure without a clear cause will have another one, usually within 6 months. You are twice as likely to have another seizure if you have a known brain injury or other type of brain abnormality. If you do have two seizures, there's about an 80% chance that you'll have more.

If your first seizure occurred at the time of an injury or infection in the brain, you are more likely to develop epilepsy than if you had not had a seizure in that situation.

More seizures are also likely if your doctor finds abnormalities on a neurological examination; a set of tests of the functioning of your nervous system that is performed in the doctor's office.

Another thing that can help your doctor predict whether you will have more seizures is an EEG, electroencephalogram (e-LEK-tro-en-SEF-uh-LOG-ram), a test in which wires attached to your scalp record your brain waves. Certain patterns on the EEG are typical of epilepsy. If your brain waves show patterns of that type, you are about twice as likely to develop epilepsy as someone who does not have those patterns.

Topic Editor: Steven C. Schachter, M.D.

What Causes Epilepsy?
There is a fine balance in the brain between factors that begin electrical activity and factors that restrict it, and there are also systems that limit the spread of electrical activity. During a seizure, these limits break down, and abnormal electrical discharges can occur and spread to whole groups of neighboring cells at once. This linkage of electrical discharges creates a "storm" of electrical activity in the brain. This is a seizure. When a person has had at least two of these seizures, that's called epilepsy.

How does epilepsy begin?
The reasons why epilepsy begins are different for people of different ages. But what's true for every age is that the cause is unknown for about half of everyone with epilepsy.

Children may be born with a defect in the structure of their brain, or they may suffer a head injury or infection that causes their epilepsy. Severe head injury is the most common known cause in young adults. In middle age, strokes, tumors, and injuries are more frequent. In people over 65, stroke is the most common known cause, followed by degenerative conditions such as Alzheimer's disease.

Why does it sometimes take years before someone with a brain injury experiences a seizure?

Often seizures do not begin immediately after a person has an injury to the brain. Instead, a seizure may happen many months later. We do not have a good explanation for this common observation, but scientists are actively researching this subject.

Topic Editor: Steven C. Schachter, M.D.

To read on the symptoms of epilepsy go to: http://www.epilepsy.com/101/ep101_symptom

http://www.epilepsy.com/101/ep101_epilepsy
http://www.epilepsy.com/101/ep101_seizure
http://www.epilepsy.com/101/ep101_cause

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