About 3 percent of persons are diagnosed with epilepsy during their lifetime, but about 70 percent of persons with epilepsy eventually go into remission.

After a first seizure, antiepileptic drugs may delay or prevent subsequent seizures, but they can cause adverse effects, and their long-term benefit is unknown. Antiepileptic drug treatment after a single seizure does not reduce the risk of drug-resistant epilepsy in the long term.

Carbamazepine, phenobarbital, phenytoin, lamotrigine, sodium valproate, and topiramate are widely considered effective in controlling seizures in newly diagnosed partial or generalized (tonic-clonic) epilepsy, but we found no randomized controlled trials comparing the drugs with placebo. A placebo-controlled trial would now be considered unethical.

• Systematic reviews found no reliable evidence on which to base a choice among anti-epileptic drugs.

• Adding second-line drugs to usual treatment reduces seizure frequency in persons with drug-resistant partial epilepsy, but increases adverse effects such as dizziness and somnolence. We do not know if any one antiepileptic drug is more likely to reduce seizures compared with others.

In persons who have been seizure-free for at least two years while on treatment, almost 60 percent of those who withdraw from antiepileptic treatment remain seizure-free, compared with almost 80 percent of persons who continue treatment.

Educational programs may reduce seizure frequency and improve psychosocial functioning in persons with epilepsy, but we do not know whether other behavioral or psychological treatments are beneficial.

There is consensus that temporal lobectomy or amygdalohippocampectomy can improve seizure control and quality of life in persons with drug-resistant temporal lobe epilepsy, but the procedures can cause neurologic adverse effects.

High-level vagus nerve stimulation may reduce seizure frequency in persons with drug-resistant partial seizures, but it may cause hoarseness and dyspnea, and long-term effects are unknown. We do not know whether different stimulation cycles more effectively reduce seizure frequency or increase the proportion of responders.

We do not know whether hemispherectomy improves seizure control in persons with drug-resistant epilepsy.

Caution: Vigabatrin, which may be used as second-line treatment, causes concentric visual field abnormalities, which are probably irreversible in about 40 percent of persons.

Definition

Epilepsy is a group of disorders rather than a single disorder. Seizures can be classified as partial or focal (categorized as simple partial, complex partial, and secondary generalized tonic-clonic seizures) or as generalized (categorized as generalized tonic-clonic, absence, myoclonic, tonic, and atonic seizures). Temporal lobe epilepsy is a form of partial or focal epilepsy. Persons are considered to have epilepsy if they have had two or more unprovoked seizures.

Incidence and Prevalence

Epilepsy is common, with an estimated prevalence in resource-rich countries of five to 10 out of 1,000 persons, and an annual incidence of 50 out of 100,000 persons. About 3 percent of persons will be diagnosed with epilepsy at some time in their lives.

Etiology

Epilepsy is a symptom rather than a disease, and it may be caused by various disorders involving the brain. The causes and risk factors include birth or neonatal injuries, congenital or metabolic disorders, head injuries, tumors, infections of the brain or meninges, genetic defects, degenerative disease of the brain, cerebrovascular disease, and demyelinating disease. Epilepsy can be classified by cause. Idiopathic generalized epilepsies (e.g., juvenile myoclonic epilepsy, childhood absence epilepsy) are largely genetic. Symptomatic epilepsies result from a known cerebral abnormality. For example, temporal lobe epilepsy may result from a congenital defect, mesial temporal sclerosis, or a tumor. Cryptogenic epilepsies are those that cannot be classified as idiopathic or symptomatic.

Prognosis

About 60 percent of untreated persons have no further seizures during the two years after their first seizure. Prognosis is good for most persons with epilepsy. About 70 percent go into remission, defined as being seizure-free for five years on or off treatment. This leaves 20 to 30 percent who develop chronic epilepsy, which is often treated with multiple antiepileptic drugs.

editor's note: Esclicarbazepine, losigamone, and retigabine are not available in the United States.