Epilepsy Health Article

Definition

Epilepsy is a condition characterized by recurrent seizures that may include repetitive muscle jerking called convulsions. A seizure is a sudden disruption of the brain's normal electrical activity accompanied by altered consciousness and/or other neurological and behavioral manifestations.

Description

Epilepsy affects 1–2% of the population of the United States. Although epilepsy is as common in adults over 60 as in children under 10, 25% of all cases develop before the age of five. One in every two cases develops before the age of 25. About 125,000 new cases of epilepsy are diagnosed each year, and a significant number of children and adults that have not been diagnosed or treated have epilepsy.

Most seizures are benign, but a seizure that lasts a long time can lead to status epilepticus, a life-threatening condition characterized by continuous seizures, sustained loss of consciousness, and respiratory distress. Nonconvulsive epilepsy can impair physical coordination, vision, and other senses. Undiagnosed seizures can lead to conditions that are more serious and more difficult to manage.

Types of seizures

Generalized epileptic seizures occur when electrical abnormalities exist throughout the brain. A partial seizure does not involve the entire brain. A partial seizure begins in an area called an epileptic focus, but may spread to other parts of the brain and cause a generalized seizure. Some people who have epilepsy have more than one type of seizure.

Motor attacks cause parts of the body to jerk repeatedly. A motor attack usually lasts less than an hour and may last only a few minutes. Sensory seizures begin with numbness or tingling in one area. The sensation may move along one side of the body or the back before subsiding.

Visual seizures that affect the area of the brain that controls sight cause people to hallucinate. Auditory seizures affect the part of the brain that controls hearing and cause the patient to imagine hearing voices, music, and other sounds. Other types of seizures can cause confusion, upset stomach, or emotional distress.

PARTIAL SEIZURES. Simple partial seizures do not spread from the focal area where they arise. Symptoms are determined by the part of the brain affected. The patient usually remains conscious during the seizure and can later describe it in detail.

COMPLEX PARTIAL SEIZURES. A distinctive smell, taste, or other unusual sensation (aura) may signal the start of a complex partial seizure.

Complex partial seizures start as simple partial seizures, but move beyond the focal area and cause loss of consciousness. Complex partial seizures can become major motor seizures. Although a person having a complex partial seizure may not seem to be unconscious, he or she does not know what is happening and may behave inappropriately. He or she will not remember the seizure, but may seem confused or intoxicated for a few minutes after it ends.

Causes & symptoms

The origin of 50–70% of all cases of epilepsy is unknown. Epilepsy sometimes results from trauma at birth. Such causes include insufficient oxygen to the brain; head injury; heavy bleeding or incompatibility between a woman's blood and the blood of her newborn baby; and infection immediately before, after, or at the time of birth.

Other causes of epilepsy include:

• head trauma resulting from a car accident, gunshot wound, or other injury
• alcoholism
• brain abscess or inflammation of membranes covering the brain or spinal cord
• phenylketonuria (PKU), a disease that is present at birth, is often characterized by seizures, and can result in mental retardation
• other inherited disorders
• infectious diseases such as measles, mumps, and diphtheria
• degenerative disease
• lead poisoning, mercury poisoning, carbon monoxide poisoning, or ingestion of some other poisonous substance
• genetic factors

Status epilepticus, a condition in which a person suffers from continuous seizures and may have trouble breathing, can be caused by:

• suddenly discontinuing antiseizure medication
• hypoxic or metabolic encephalopathy (brain disease resulting from lack of oxygen or malfunctioning of other physical or chemical processes)
• acute head injury
• infection spread from blood (for example, meningitis or encephalitis) caused by inflammation of the brain or the membranes that cover it