Causes of Epilepsy & Seizures
Epilepsy is not associated with any particular disease. Many abnormalities of the nervous system can result in seizure activity. Seizures can also occur in the normal nervous system when its metabolic balance is disturbed. The etiology (cause) of epilepsy may be idiopathic (not clearly known) or related to a particular disease state. About 35 percent of all cases of epilepsy have no clearly definable cause.
Genetic factors: It is now accepted that some persons may have a genetic predisposition to the development of seizures. There is also an increased incidence of epilepsy in relatives of those with a seizure disorder.
Head injury: Seizures may develop at or around the time of injury or years after (usually not more than two years later). They may occur with either an "open" or "closed" head injury.
Stroke/cerebrovascular disorders: Seizures can occur at the time of a stroke or many years later. They may occur with strokes that result in lack of blood flow to the brain or with those that involve bleeding into or around the brain.
Metabolic disturbances: This group of disorders changes levels of various metabolic substances in the body. These disease states sometimes result in seizures.
- Electrolyte disturbances (altered levels of sodium, calcium, or magnesium)
- Hypoglycemia (low blood sugar) or hyperglycemia (elevated blood sugar)
- Renal failure (kidney disease) with uremia (increased urea in the blood) or changes that occur around the time of kidney dialysis
- Hepatic failure (severe liver disease) and elevation of associated toxins
- Hypoxia (lowered oxygen delivery to the brain)
Toxic causes: The presence of certain drugs can cause seizure activity. In addition, abrupt withdrawal of some substances can lead to seizure activity. These substances that may induce seizures include the tricyclic antidepressants, lithium, antipsychotic medications, aminophylline, and high doses of penicillin.
Illicit drug use, particularly cocaine, heroine, amphetamines, and PCP, can cause seizures. Alcohol withdrawal can be associated with seizure activity. These seizures usually occur 12-24 hours after the last drink but can occur up until 48 hours or more after binge drinking.
Withdrawal from prescription drugs and agents such as barbiturates and narcotics can result in seizure activity.
Infections: Infections of the nervous system may result in a lowered seizure threshold. These may include meningitis (infections of the coverings of the brain and spinal fluid), encephalitis (infection of the brain itself), and HIV (human immunodeficiency virus), and related infections.
Tumors and space-occupying lesions: Brain tumors, both malignant (cancerous) and benign, may be associated with seizures. The anatomic location of the abnormality influences the likelihood of having seizures.
Degenerative disorders: There are many neurodegenerative disorders that are accompanied by seizures. These include tuberous sclerosis, neurofibromatosis, Tay-Sachs disease, phenylketonuria (PKU), and Sturge-Weber syndrome.
Brain damage in infancy: Cerebral palsy secondary to lack of oxygen, infection, or trauma is associated with epilepsy.
Febrile seizures: These are an age-associated form of epilepsy that may present as a single seizure or may be recurring. They are associated with a high fever in children 3 months to 4 years of age and occur in 3–4 percent of children.