Epilepsy is a chronic neurological disorder characterized by repeated unprovoked seizures, with worldwide distribution. The incidence of epilepsy ranges from 23 to 190 per 100,000 population per year and is higher in developing countries than in industrialized countries and in lower socio-economic classes. The incidence of acute symptomatic seizures is 29-39 per 100,000 per year and the incidence of isolated seizures is 61 per 100,000 per year. The incidence of epilepsy is moderately higher in men than in women and is higher in the two extremes of the age spectrum. By age 80, there is a 1.3 to 4% risk of epilepsy, a 8% risk of epilepsy and single seizures, and a 10% risk when including acute symptomatic seizures. A documented etiology of epilepsy has been reported to vary from 14 to 52% of cases in incidence studies, with cerebrovascular disease, congenital neurological disorders, trauma, neoplasms, degenerative disorders and infections in decreasing order. Complex partial seizures are the predominating seizure pattern, followed by generalized tonic-clonic seizures, simple partial seizures, absence seizures, and myoclonic seizures. The incidence varies significantly according to the epilepsy syndrome. The overall prevalence of epilepsy is 2.7-41 per 1,000 (mostly 4-8 per 1,000). The prevalence is lower in industrialized than in developing countries and is higher in patients with lower socio-economic background. The prevalence tends to prevail in men and in blacks and varies with age, with differing rates in children, adults, and the elderly. Documented etiology in prevalent cases varies from 17 to 56%. The overall prognosis of epilepsy is favorable, with 55-68% of newly diagnosed cases achieving seizure remission. The average recurrence risk of a first unprovoked seizure is 51%, about 50% of recurrences occurring within 6 months. Factors influencing the prognosis of epilepsy include etiology, EEG abnormalities, generalized tonic-clonic seizures, the number of seizures experienced after the onset of treatment, and thesyndromic pattern. Antiepileptic drugs suppress seizures but do not alter the long-term prognosis of epilepsy. About 50% of patients are successfully controlled by the first drug. The average risk of relapse after treatment discontinuation in seizure-free patients is 25% at one year and 29% at two years. The mortality of epilepsy is mostly 1-2 per 100,000 per year, with a standardized mortality ratio (SMR) of 1.6-5.3. Mortality is higher in developing countries. Status epilepticus, generalized tonic-clonic seizures and myoclonic seizures are associated with an increased mortality. Seizure etiology is one of the strongest risk factors for mortality in epilepsy. Accidents and suicide are among the commonest causes of death. The SMR is inversely correlated to age and disease duration. The incidence of sudden unexplained death (SUDEP) is 1-3.5 per 1,000.
|Title of host publication||Handbook of Clinical Neuroepidemiology|
|Publisher||Nova Science Publishers, Inc.|
|Number of pages||43|
|ISBN (Print)||1600215114, 9781600215117|
|Publication status||Published - 2007|
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)