The causes of epilepsy relate to various medical conditions, brain concussion, and in some cases, unknown factors. The disorder arises when these conditions disrupt the connections between neurons, an imbalance in the neurotransmitters that deliver signals between nerves, or a combination of the two.
Sometimes abnormalities develop early in life related to genetic factors, exposure to infections and injury. Some people acquire epilepsy later in life. Among the more common causes of epilepsy are:
- Infections of the brain such as meningitis, brain abscesses, and encephalitis
- Traumatic injuries to the head
- Brain injury occurring during or soon after birth
- Oxygen deprivation caused by reduced blood supply to brain cells
- Brain tumors
- Abnormally formed blood vessels in the brain (arteriovenous malformations)
- Genetic disorders
- Congenital metabolic conditions
- Neurological disorders such as Alzheimer’s disease
No underlying cause for epilepsy can be determined in about 66 percent of cases. It is idiopathic when related to inherited disorders, a cryptogenic if no known related factors are present.
A number of environmental and lifestyle factors can trigger epileptic seizures. These include exposure to lead, carbon monoxide and other poisons. Cigarette smoke, overdoses of medications such as antidepressants and amphetamines, and abuse of illicit drugs such as cocaine also bring about seizures. Lack of sleep is another of the high-risk causes of seizures, even in people with symptoms controlled by treatment.