Epilepsy

Epilepsy is the third most common neurological disorder in the United States (after stroke and Alzheimer's disease) and affects 2.7 million people. Electrical disturbances in the brain cause seizures that result in changes in a person's sensation, awareness, or behavior, and often cause convulsions.

Typically, neurons in the brain generate electrical signals that travel toward other neurons. Two kinds of neurotransmitters, excitatory and inhibitory, exist in equal amounts in a normal functioning brain, and this helps keep the brain from being overwhelmed with electrical activity. When there is an imbalance of these neurotransmitters, too many neurons fire (send an electrochemical message) at once or some neurons fire much more rapidly than usual. For example, neurons in the average brain fire approximately 80 times a second; during a seizure, the affected neurons may fire 500 times a second. When there is a sudden change in this electrical activity, it affects the way cells communicate (send signals to each other). This results in a person having strange sensations, behavior, emotions, convulsions or seizures, muscle spasm, and loss of consciousness and is called epilepsy. The electrical changes in the brain can happen occasionally or hundreds of times a day.

There are numerous kinds of epilepsy. The more common ones include:

Absence epilepsy;
Temporal lobe epilepsy;
Neocorticol epilepsy;
Lennox-Gastaut syndrome; and
Rasmussen's encephalitis.

Epileptic seizures are divided into two main categories: partial (or focal) and generalized. Partial seizures occur in just one part of the brain, and generalized seizures are electrical disturbances on both sides of the brain.

Epilepsy is not a progressive condition, and some children with epilepsy go into remission during adolescence. This is especially true in children with epilepsy of unknown cause.

Women with epilepsy who want to get pregnant need to thoroughly discuss their condition with their physician. Children born to a woman with epilepsy are twice as likely to have a birth defect as other children.

Most people with epilepsy can lead relatively normal lives. They may need to establish coping strategies for certain restrictions that epilepsy can cause in their lives, such as the inability to have a driver's license in some states. Cultivating and maintaining a positive outlook and independence helps people with epilepsy thrive.

WHAT ARE THE SYMPTOMS?

Partial, or focal, seizures that originate in one hemisphere (part) of the brain may be simple or complex. The difference is that during simple partial seizures, a person remains conscious, whereas with complex seizures, they lose consciousness.

Symptoms of a simple partial seizure are:

Uncontrolled shaking of a part of the body;
Unusual feeling, such as sudden joy, anger, or sadness; and
Unusual sensation, such as hearing, smelling, tasting, seeing, or feeling something that is not real.

Symptoms of a complex partial seizure include:

Aura (an unusual warning sensation that a seizure is about to occur);
A change in or loss of consciousness;
Repetitious behavior (such as blinking, twitching, lip smacking, or walking in a circle); and
A dream-like feeling.

After a complex partial seizure, a person may be confused and experience memory loss.

Generalized seizures include absence, tonic, clonic, myoclonic, atonic, and tonic-clonic seizures. The symptoms of each include:

Absence or non-convulsant seizures: Staring, twitching muscles (such as the eyelids), brief loss of consciousness, and wandering aimlessly.
Tonic seizures: Stiffening muscles, especially those in the arms, back, and legs.
Clonic seizures: Repeated jerking of the muscles.
Myoclonic seizures: Sudden, brief jerks of the head, arm, or leg, or some combination.
Atonic seizures: Loss of muscle tone, which are also called "drop attacks" because the person's head drops or the person collapses or falls down suddenly.
Tonic-clonic seizures. Loss of consciousness, body stiffening and shaking (convulsions), loud vocalization (crying out), drooling, and occasional tongue biting or loss of bladder control. (People cannot swallow their tongue, as some believe.)

After a person has an epileptic seizure, he or she often regains consciousness within minutes and may feel exhausted, dazed, confused, embarrassed, and may have a headache.

Epilepsy syndromes are different kinds of epilepsy and each shares characteristics such as seizure triggers, behavior induced by a seizure, brain wave patterns on an electroencephalogram (EEG), and hereditary factors. Some epilepsy syndromes and their primary symptoms include:

Absence epilepsy (loss of consciousness, staring, jerking arms, blinking rapidly, and lip-smacking);
Lennox-Gastaut syndrome (severe epilepsy with atonic seizures that requires wearing a protective helmet, impaired intellectual development, and behavior problems);
Temporal lobe epilepsy (aura that can cause déjà vu, panic, anxiety, or joy);
Frontal lobe epilepsy (weakness, jerking motions, inability to speak, involuntary actions such as laughter or screaming); and
Rasmussen's encephalitis (loss of function on one side of the body, language problems, and mental retardation).

CAUSES AND RISK FACTORS

The majority of epilepsy cases (65 percent) have no known cause. There are many possible causes for the remaining 35 percent, including any condition or disease that affects the brain. Conditions that may lead to epilepsy include:

Cerebrovascular disease;
Developmental neurological disorder (cerebral palsy, retardation);
Head injury;
Tumor;
Brain injury before or during birth;
Infections that affect the brain such as meningitis or encephalitis;
Chemical imbalance (low blood sugar or low sodium);
Exposure to street drugs or certain poisons such as carbon monoxide or lead;
Alcohol withdrawal;
AIDS;
Alzheimer's disease; and
Celiac disease (allergy to wheat gluten).

Epilepsy may also be inherited; it runs in families, and genetic abnormalities appear to contribute significantly to the condition. Seizures can be provoked or unprovoked. When provoked, triggers include:

Lack of sleep;
Alcohol consumption;
Stress;
Hormonal changes due to menstruation;
Flashing or flickering light; and
Smoking.

People are at greater risk for developing epilepsy if they have:

Autism;
Down's syndrome;
Depression; or
Multiple sclerosis.

DIAGNOSIS

Many people will experience a seizure in their lifetime, but a single seizure is not indicative of epilepsy. If a person has 2 or more seizures, epilepsy will be considered a possible cause. A physician will begin by taking a detailed medical history and a physical and neurological examination. A blood or urine test may be given to help determine whether there is an underlying cause such as poisoning or infection.

The physician may order an electroencephalogram (EEG) to determine what type of seizure the patient has had. Video monitoring is often used simultaneously to record behavior accompanying the EEG.

Another important tool the physician may use is a brain scan to identify abnormalities. The most common brain imaging techniques are:

Computed tomography (CT) scan;
Positron emission tomography (PET);
Magnetic resonance imaging (MRI); and
Magnetoencephalogram (MEG).

TREATMENT APPROACH

The goal of treatment for epilepsy is to stop seizures with few side effects.

If an underlying health condition, such as alcoholism or meningitis, is associated with epilepsy, treating that condition may stop seizures. For other types of epilepsy, the primary treatment is medication that prevents seizures, called anti-epileptics or anticonvulsants. A key goal of treating epilepsy with medication is monotherapy (single drug therapy).

If medication fails to control seizures, other treatment options include surgery, diet therapy, and a pacemaker-like device that delivers electrical pulses to the brain. Types of surgery may include:

Corpus colostomy;
Hemispherectomy;
Lesionectomy;
Lobectomy; and
Multiple subpial transection.

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