Epilepsy - Causes

Hydrocephalus and Shunts. Hydrocephalus occurs when cerebrospinal fluid (CSF) accumulates in the brain, leading to excessive swelling of the brain ventricles. The resulting pressure can damage the brain's tissue. Hydrocephalus itself is not commonly known to cause seizures, but its treatment, which involves insertion of a shunt, may be. The shunt is a device that drains the excess fluid from the brain. One 2001 study noted that up to half of children who receive shunts may experience epileptic seizures, particularly if the shunt is placed before age two. More research on its relationship to epileptic seizures is needed.

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Focal Cortical Dysplasia. This is an abnormality in fetal development in which the normal migration of nerve cells is altered. It can cause very severe epilepsy that is difficult to treat.

Other Causes of Seizures in Children. Seizures in infants and children may be due to birth defects, difficulties during delivery, or poisoning.

Causes of Adult-Onset Seizures

Alcohol Abuse. Alcohol abuse is one of the most common causes of adolescent- and adult-onset seizures. Seizures, nearly always generalized tonic-clonic, occur in about 10% of adults during withdrawal. Multiple seizures happen in about 60% of these patients. The first seizure occurs 7 hours to two days after the last drink, and the time between the first and last seizure is usually six hours or less. [For more information, see In-Depth Report #56: Alcoholism.]

Head Injuries in Adults. Head injuries to adults can cause seizures, with the risk highest in severe head trauma. A first seizure related to the injury can occur years later. People with mild head injuries, which involve loss of consciousness for less than 30 minutes, have only a slight risk that lasts up to five years after the injury.

Sleep Disorders. Some sleep disorders, such as obstructive sleep apnea or narcolepsy, have been associated with seizures, although a causal relationship is unclear. Sleep apnea and hereditary nocturnal frontal lobe epilepsy have very similar symptoms (feeling of choking, abnormal motor activity during sleep, and excessive sleepiness during the day). A 2000 study reported that one-third of patients with epilepsy who did not respond to medications were later diagnosed with obstructive sleep apnea. Other studies have found that when sleep apnea is treated in patients with both epilepsy and the sleep disorder, seizure activity decreases. More research is needed.

Stroke. Seizure is a symptom of a major stroke. In some cases, injury to the brain from small strokes may cause seizures. Studies report that between 15 -23% of stroke patients consequently have seizures. A 2005 study found that 3% of patients who have had a stroke go on to develop epilepsy. Patients who had a severe stroke were 5 times more likely to develop epilepsy than patients who had a mild stroke.