Epilepsy

موضوع: Epilepsy الإثنين يناير 03, 2011 12:22 pm

Epilepsy is a condition of the nervous system that causes repeated,
sudden, brief changes in the normal electrical activity of the brain.
During one of these epileptic episodes, commonly called a seizure or
convulsion, brain cells fire uncontrollably at up to four times their
normal rate, temporarily affecting the way a person behaves, moves,
thinks or feels.

There are two main types of seizures:
A primary generalized seizure involves the entire brain.
A partial seizure begins in one brain area, called a focus, and affects only part of the brain.
Many conditions can affect the brain and trigger epilepsy, including:

Brain injury, either before or after birth
Brain tumors
Infections, especially meningitis and encephalitis
Genetic conditions, including tuberous sclerosis
Abnormal blood vessels in the brain
Lead poisoning
However, in about 70% of people with epilepsy, the specific cause is unknown.
Approximately
2.7 million Americans have active epilepsy. Each year, about 200,000
people are diagnosed with epilepsy in the United States, and up to 25%
of these are children under the age of 15. Epilepsy is most common
under the age of 2 and over the age of 65.

Symptoms
The symptoms of epilepsy vary depending on how much of the brain is affected and where the affected area is located.

Primary generalized seizures (involve all areas of the brain):

Generalized
tonic-clonic seizure (also called grand mal) — In this type of seizure,
the person loses consciousness, falls to the ground and temporarily
stops breathing. All body muscles then contract (tense up) at once for
a short period. This is soon followed by a series of shorter rhythmic
contractions. Some people also lose bowel or bladder control (become
incontinent). The seizure episode may last for a few minutes and is
followed by a period of sleepiness (lethargy) and confusion, and
possibly muscle soreness and a headache.

Absence seizure
(also called petit mal seizure) — In this type of seizure, loss of
consciousness is so brief that the person usually doesn't change
position. For a few seconds, the person may have a blank stare, blink
rapidly, make chewing movements with the mouth, or briefly move an arm
or leg rhythmically. This type of seizure usually begins in childhood
or early adolescence.
Partial (focal) seizures (begin in a single area of the brain):

Simple
partial seizure — In this type of seizure, the person remains awake and
aware. Symptoms vary depending on the brain area involved and can
include jerking movements in one part of the body; an experience of
abnormal smells, sounds or changes in vision; nausea; or emotional
symptoms, such as unexplained fear or rage.

Complex partial
seizure — In this type of seizure, the person may seem to be aware, but
is briefly unresponsive. There may be a blank stare, chewing or lip
smacking, repetitive movements of the hand, or unusual behaviors. After
the seizure, the person has no memory of the episode.
A partial seizure can turn into a generalized seizure if the electrical activity spreads to the rest of the brain.

Status
epilepticus — This condition occurs when a person has a generalized
seizure that lasts 20 to 30 minutes or more, or a series of seizures
without fully regaining consciousness. This is a life-threatening
medical emergency.

Diagnosis
You may not have any seizure
symptoms when you visit your doctor's office. For this reason, it is
important to ask anyone who witnessed your seizure to describe the
event, and to write it down for your doctor. This description will help
your doctor determine the type of seizure you had and decide on
appropriate treatment.

Having a seizure does not mean that a
person has epilepsy. For example, it's common for children to have
seizures associated with fever, and most children who have them do not
go on to develop epilepsy. Your doctor will diagnose epilepsy based on
your history, a thorough physical and neurological examination, and the
results of an electroencephalogram (EEG). In many cases, your doctor
will order a computed tomography (CT) scan or magnetic resonance
imaging (MRI) scan of the brain. Other types of brain scans also may be
needed, such as positron emission tomography (PET) or single photon
emission computed tomography (SPECT). To check whether your seizures
are related to medical causes outside the brain, your doctor may order
basic lab tests including blood tests, urinalysis and an
electrocardiogram (EKG).

Expected Duration
Epilepsy can be
a lifelong condition, but many people with a history of multiple
seizures eventually will stop having seizures. People who are younger
when seizures start and people who have a normal neurological
examination are more likely to become seizure-free at some point. For
most people with epilepsy, seizures can be controlled with medication.

Prevention
Since
the cause of most cases of epilepsy remains unknown, there is no way to
prevent seizures. To help prevent epilepsy caused by head injury, you
can:

Wear seat belts while driving
Equip your car with air bags
Wear an approved helmet while skating, riding a motorcycle or bicycling
Use protective headgear for sports
For
people with an active seizure disorder, it is also important to take
precautions to minimize the risk of injury if a seizure should occur.
For this reason, it is generally recommended that people with epilepsy
do not operate a motor vehicle or other dangerous machinery for at
least six months after the most recent seizure.

People with
epilepsy may find it helpful to wear a medical identification bracelet
or other form of identification that describes their condition. This
will provide important information about their epilepsy to emergency
personnel in case a seizure episode occurs when they are away from home.

Treatment
In
most cases, your doctor will begin treatment with one of the many
available antiepileptic medications. These medications include
carbamazepine (Tegretol), clonazepam (Klonopin), ethosuximide
(Zarontin), felbamate (Felbatol), gabapentin (Neurontin), lamotrigine
(Lamictal), phenobarbital (Solfoton), phenytoin (Dilantin), primidone
(Mysoline), topiramate (Topimax) and valproic acid (Depakene,
Depakote). The type of medication used depends on the type of seizure
being treated.

When medication fails to control a person's
seizures, surgery may be considered. The decision to perform surgery
depends on many factors, including the frequency and severity of
seizures, the patient's risk of brain damage or bodily injury from
frequent seizures, the effect on quality of life, the person's overall
health, and the likelihood that surgery will control seizure episodes.

Status
epilepticus, a life-threatening medical emergency, is treated with
medications given intravenously (into a vein) or rectally, together
with protective measures to keep the person's airway open and to
prevent injury to the person's head and tongue.