Chapter 11 - Seizure disorders

Abstract

Seizures are abnormal, uncontrolled electrical discharges in the cortical gray matter of the brain. They transiently interrupt normal function and usually cause abnormal sensations, altered awareness, involuntary focal movements, or generalized convulsions. Epilepsy is a chronic brain disorder that usually involves two or more recurrent, unprovoked seizures that are unrelated to reversible stressors. Generalized seizures involve abnormal electrical activity that begins in both brain hemispheres at the same time—they include absence, atonic, tonic, clonic, tonic-clonic, myoclonic, and febrile seizures. Partial seizures are also called focal seizures, are the type generally accompanied by auras (mostly with visual abnormalities), with the subtype called complex partial seizures being the most common type of seizure in adults with epilepsy. Status epilepticus is very rare, with long-lasting or multiple recurring seizures that indicate a true medical emergency, able to cause permanent brain damage or death. Electroencephalography is the most common testing method used to diagnose epilepsy. Sudden, unexpected death of epileptic patients occurs in 1.2 of every 1000 patients annually. Tonic-clonic seizures have the greatest risk of sudden unexpected death out of all the different generalized seizures. Most seizures are somewhat preventable by following medication regimens. The prevalence and incidence of epilepsy are slightly higher in men and often peak in the elderly.