Epilepsy (epilepsy): When nerve cells in the brain fire electrical impulses at a rate four times higher than normal, this causes a sort of storm in the brain known as a seizure. structure of repeated seizures is called epilepsy. Known causes include head injuries, brain tumors, lead poisoning, congenital malformations of the brain, genetic and infectious diseases. But fully half of cases no cause can be found. Drug control seizures for most patients.