An epileptic seizure is caused by a surge of electrical energy to the brain, which causes the messages passing between the brain cells to be mixed up or interrupted. Since everything that your body does is connected to the brain, a disruption to the brain function can have a great many different effects in the rest of the body. That's why there are so many different types of seizure.

In more than half of cases, it's not sure what actually causes the brain disturbance in the first place, though in other cases it's known to be the result of an accident, illness or stroke.

No cure for epilepsy exists at present, though research is still going on. However, it can be very successfully treated with drugs that make seizures less severe or frequent, or in some cases even stop them.

You can find a very full overview of the condition, with links to other useful sites, here.