Epilepsy: Causes and Diagnosis

by Food and Drug Administration (FDA)

George Thomas was 21 years old when his life changed: As he stood in his girlfriend's yard, he was hit by a car. After spending a week in the hospital, he was released. But over the next five years, the athletic Thomas began experiencing dizzy spells. At first he shrugged them off as a result of over-exercise or bad diet.

"Then one day I crashed right out of the shower," Thomas recalls. "After that I had frequent grand mal seizures."

The diagnosis was epilepsy, a disease with myriad causes, one of which is the kind of head injury Thomas experienced. The seizures totally changed his active, athletic lifestyle.

"I couldn't ride my bike, I was too dizzy," says Thomas, a cross-country cyclist. "My vision stunk. I had my driver's license taken away; when I had to write a check, people would ask why a guy in his mid-20s didn't have a license. The word epilepsy was a stigma."

Thomas tried a variety of anticonvulsant medications, taking up to 16 pills a day at one point. One day, as his wife drove the newly married Thomas to a doctor's appointment, he had a terrible seizure. He couldn't move, and he threw up all over himself.

"My doctor said we'd try to look at something else," he says.

"Something else" was Thomas' decision to become part of clinical trials for a new drug called Lamictal (lamotrigine) in 1989, which was subsequently approved by the Food and Drug Administration in 1994. He has not had a seizure since. Today the 35-year-old Thomas is the father of a 7-year-old daughter, a professional speaker, and an "ultra distance" bicycle racing champion who races bikes cross country.

Thomas has plenty of company when it comes to battling epilepsy. Over 2 million people in America have the disorder, and the worldwide numbers-50 million estimated cases-are even more staggering. On a global basis, nearly three-quarters of those with epilepsy receive no treatment for their seizures. Shrouded in mystery since ancient times, epilepsy remains a complex and challenging condition that continues to baffle both doctors and researchers.

Although special diets and even surgery are used to prevent seizures, the most common treatment for epilepsy is daily use of anticonvulsant drugs. People with epilepsy may take medicine up to four times a day to prevent seizures; response to the various medicines depends on the individual and the type of seizures being treated.

The oldest drugs used in epilepsy treatment include phenobarbital, introduced in 1912, and Dilantin (phenytoin), in use since 1938. Altogether there are nearly two dozen different drugs approved for epilepsy treatment. The most recent drugs FDA has approved include Felbatol (felbamate) and Neurontin (gabapentin), approved in 1993; Lamictal (lamotrigine), approved in 1994; Topamax (topiramate), approved in 1996; and Gabitril (tiagabine), approved in 1997.

In 1997, FDA also approved Diastat, the first at-home alternative for the intravenous form of the drug diazepam, already used by emergency rooms to break a chain of seizures. Diastat is a gel form that can be administered rectally. Designed specifically for patients affected by multiple, frequent seizures, Diastat reaches the bloodstream in about two minutes. If not halted, such seizures can be fatal.

Diastat gel has helped Eric Warner, 13, of Forest Lake, Minn., tremendously, says his mother Linda.

Following a brain infection when he was 2 months old, Eric suffered with repeated episodes of long-lasting seizures. "[Eric] started using Diastat in October 1997," Warner says. "With Diastat, you wait three minutes into the seizure, and if [it continues], you give it to him and it only takes a few minutes to work."

Warner says Diastat has cut down on trips to the emergency room with Eric. He also takes Vigabatrin, still under investigational study here, that is imported from Europe (with FDA approval, she notes) as well as Tegretol (carbamazepine).

With the help of these drugs, Warner is convinced Eric will be a writer someday.

"His strength is writing," she explains. "I look at what treatment is like now since he was first diagnosed there is so much research going on that I am very encouraged."

"There had not been a new chemical entity approved for epilepsy since 1978 the early 1990s began a new era in anticonvulsant drug approvals," says Russell Katz, M.D., deputy director of FDA's division of neuropharmacological drug products. "The research, of course, started years before that. Part of [FDA's approval of these drugs] has to do with the progress of understanding and evaluating clinical trials to evaluate these drugs. FDA has been actively working with [drug] companies to improve the science of evaluating anticonvulsant drugs." Katz adds that the National Institutes of Health also have been active in this pursuit as well.

Causes and Diagnosis

"There are at least 150 underlying causes of epilepsy," says Peter Van Hazerbeke, public relations director for The Epilepsy Foundation. In 70 percent of cases, however, no known cause of epilepsy is ever found. Some of the known causes include brain injuries, infections that damage the brain, tumors, disturbances in blood circulation to the brain (such as stroke), high fevers, lead or other poisoning, and maternal injury.

Seizures and epilepsy are not the same: Seizures are a symptom of epilepsy. Epilepsy is a neurological condition that can produce brief disturbances in the brain's electrical functions. Normally, brain cells communicate with each other via electrical impulses working together to control body movements and keep organs functioning properly. When someone has epilepsy, this normal pattern may be interrupted by thousands to millions of electrical impulses that occur at the same time and are more intense than usual, producing abnormal brain electrical activity and resulting in a seizure. These bursts of electrical impulses can affect body movements, sensations or consciousness.

Epilepsy is diagnosed mainly via interpretation of a patient's medical history; the patient describes what the seizures were like and, when a patient can't recall the seizures, witnesses also may be asked to describe what they saw.

About the Author

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