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Epilepsy
Alternative names
Seizure disorder
Definition
A brain disorder involving
recurrent seizures.
Causes
and risks
A seizure disorder includes any condition in
which there are repeated episodes of seizures
of any type. Epilepsy is a term used when the
seizure disorder has no identifiable cause,
such as brain disease. A seizure disorder affects
about 0.5% of the population. 1.5-5.0% of the
population may have a seizure in their lifetime.
It can affect people of any age.
Information in the brain is transmitted from
nerve cell to nerve cell by an electrochemical
process. This process can be detected as electrical
activity by an electroencephalograph (EEG).
Seizures are associated with abnormal patterns
of electrical activity.
The cause of the seizure correlates, to some
extent, with the age of onset. In some people,
seizures may be triggered by hormone changes
such as pregnancy or menstruation. They may
also be triggered by illness or sensory stimuli
such as lights, sounds, and touch. In many cases,
no trigger is found for the seizures.
Given sufficient circumstances, any person
will have a seizure. The amount of stimulation
required to cause a seizure is called the "seizure
threshold." Many people with epilepsy are considered
to have a low seizure threshold.
Some of the more common causes of seizures include:
- Idiopathic (no identifiable
cause)
- usually begin
between ages 5 to 20
- can occur at
any age
- no other neurologic
abnormalities present
- often a family
history of epilepsy or seizures
- Developmental or
genetic conditions present at birth, or injuries
near birth-- in this case, the seizures usually
begin in infancy or early childhood
- Metabolic abnormalities
- may affect any
age
- diabetes mellitus
complications
- electrolyte imbalances
- kidney failure,
uremia (toxic accumulation of wastes)
- nutritional deficiencies
- phenylketonuria
(PKU)--can rarely cause seizures in infants
- other metabolic
diseases such as inborn error of metabolism
- use of or intoxication
from alcohol or drugs
- withdrawal from
alcohol
- withdrawal from
drugs
- Brain injury
- may affect any
age, highest incidence in young adults
- most likely if
the brain membranes are damaged
- seizures usually
begin within 2 years after the injury
- early seizures
(within 2 weeks of injury)--do not necessarily
indicate that chronic seizures (epilepsy)
will develop
- Tumors and brain
lesions that occupy space (such as hematomas)
- may
affect
any age, more common after age 30
- partial (focal)
seizures most common initially
- may progress
to generalized tonic-clonic seizures
- Disorders affecting
the blood vessels (stroke, TIA, and so on)
- most common cause
of seizures after age 60
- Degenerative disorders
(senile dementia Alzheimer type, or similar
organic brain syndromes)
- mostly affect
older people
- Infections
- may affect all
ages
- may be a reversible
cause of seizures
- brain infections
(meningitis, encephalitis)
- brain abscess
- acute severe
infections of any part of the body
- chronic infections
(such as neurosyphilis)
- complications
of AIDS or other immune disorders
The type of seizure that occurs varies depending
on the location and type of the problem causing
the seizure and individual response to the problem.
There are two major types of seizures:
- Generalized seizures --
affect all or most of the brain
- Partial seizures -- affect
only a portion of the brain
Epilepsy typically involves generalized seizures
(except in some cases that develop in childhood
and have a specific focus). Two major kinds
of generalized seizures are tonic-clonic ("grand
mal") seizures and petit mal seizures.
Partial seizures include focal seizures (during
which the person remains alert but there are
abnormal movements or sensations) and partial
complex seizures (during which the abnormal
movement or sensation is accompanied by changes
in consciousness).
Prevention
Generally, there is no known
prevention for seizure disorders. However, adequate
diet and sleep and abstinence from drugs and alcohol
may decrease likelihood of precipitating a seizure.
Symptoms
Epilepsy is characterized by seizures of any
type that occur on a chronic, recurrent basis
and have no known cause. In addition to seizures,
there may be other symptoms or signs, such as
headache, changes in mood or energy level, dizziness,
fainting, confusion, and memory loss.
An aura (sensations indicating a seizure is
imminent), occur in some persons just prior
to a generalized seizure.
SYMPTOMS OF GENERALIZED SEIZURES
Petit mal seizures:
- Minimal or no movements (usually, except
for "eye blinking") -- may appear like a blank
stare
- Brief sudden loss of awareness or conscious
activity -- may only last seconds
- Recurs many times
- Occurs most often during childhood
- Decreased learning (child often thought
to be daydreaming)
Tonic-clonic (grand mal) seizures:
- Whole body, violent muscle contractions
- Rigid and stiff
- Affects a major portion of the body
- Loss of consciousness
- Breathing stops temporarily, then "sighing"
- of urine
- Tongue or cheek biting
- Confusion following the seizure
- Weakness following the seizure (Todd’s paralysis)
SYMPTOMS OF PARTIAL SEIZURES
Simple partial (focal) seizures:
- Muscle contractions of a specific body part
- Abnormal sensations
- May have nausea, sweating, skin flushing,
and dilated pupils
- May have other focal (localized) symptoms
Partial complex seizures:
- Automatism (automatic performance of complex
behaviors)
- Abnormal sensations
- May have nausea, sweating, skin flushing,
and dilated pupils
- May have other focal (localized) symptoms
- Recalled or inappropriate emotions
- Changes in personality or alertness
- May or may not lose consciousness
- Olfactory (smell) or gustatory (taste) hallucinations
or impairments -- if temporal focus
Signs
and tests
The diagnosis of epilepsy
and/or seizure disorders involves a history of
recurrent seizures of any type. A physical examination,
including a detailed neuromuscular examination,
may be normal or may show focal neurologic deficits
(localized abnormalities of brain functions).
- An electroencephalograph (EEG), a reading
of the electrical activity in the brain, usually
confirms the presence of various types of
seizures. It may, in some cases, indicate
the location of the lesion causing the seizure.
A normal EEG does not rule out a seizure disorder.
Tests for the cause may include various blood
tests (as appropriate depending on the suspected
cause), including:
- A CBC
- A blood chemistry, blood glucose
- Liver function tests
- Kidney function tests
- Tests for infectious diseases
- A CSF (cerebrospinal fluid) analysis
Tests for the cause may include procedures such
as:
- A head CT or MRI scan
- A lumbar puncture (spinal tap)
A physical examination and testing may be used
to rule out other temporary and reversible causes
of seizures such as a fever, various temporary
chemical imbalances, toxemia of pregnancy, withdrawal
from alcohol or drugs (especially benzodiazepines
and barbiturates), use of drugs (especially street
drugs), or other causes.
Disorders that may cause symptoms resembling seizures
include transient ischemic attacks, rage or panic
attacks, and any disorder that causes loss of
consciousness or that causes tremors or tics as
symptoms (abnormal muscle movements that are not
caused by abnormal brain electrical activity).
Treatment
FIRST-AID FOR TONIC-CLONIC SEIZURE
- Protect the person from injury. Do not attempt
to force a hard object (such as a spoon or
tongue depressor) between the teeth, because
you can cause more damage than what you are
trying to prevent!
- Clear the area of furniture or other objects
that may cause injury from falls during the
seizure. Do not attempt to restrain or hold
the person down during the seizure.
- Protect from aspiration (inhaling) of vomit
or mucus. Turn the person onto the side if
vomiting occurs. Keep the person on the side
while he or she sleeps after the seizure is
over.
If the person having seizures turns blue or
stops breathing, turn him or her to the side
to keep the airway open and prevent the tongue
from obstructing the airway. Breathing usually
starts on its own once the seizure is over.
CPR or mouth-to-mouth breathing is rarely needed
after seizures and cannot be performed during
the seizure.
EMERGENCY MEDICAL TREATMENT
Repeated or prolonged seizures (status epilepticus)
may cause severe lack of oxygen in the body.
This is a medical emergency!
- Obtain professional medical assistance immediately.
- Measures to protect the airway may be needed,
including use of tubes to keep the airway
open. Breathing should be supported as appropriate.
- Intravenous glucose and thiamine may be
administered to the person on the chance that
low blood sugar or low thiamine is responsible
for the seizure.
- Medications such as diazepam (Valium) or
lorazepam, or anticonvulsant medications (such
as phenytoin and phenobarbital) may be used
to control prolonged, repeated, generalized
seizures. They are usually injected into a
vein. Other medical treatment may be indicated,
including use of general anesthesia with neuromuscular
blockade ("muscle paralyzers").
- After status epilepticus is controlled,
oral anticonvulsants are begun and tests are
performed to determine the cause of the condition.
AFTER A SEIZURE
Record details of the seizure for the health
care provider -- date and time of the seizure,
how long it lasted, which body parts were affected,
the type of movements or other symptoms, possible
causes, and other factors noted.
Isolated seizures are treated based on the type
of seizure and the suspected cause (see the
specific seizure type for details). Generally,
this includes treatment of the cause and/or
use of anticonvulsant medications.
Treat any injuries from bumps or falls.
AFTER DIAGNOSIS OF EPILEPSY
Treatment of causes, if a cause has been identified,
may stop the occurrence of seizures. This may
include medical treatment of disorders, surgical
repair of tumors or brain lesions, or other
treatments.
Oral anticonvulsants prevent or minimize the
number of future seizures. Response is individual,
and the medication used and dosage may have
to be adjusted repeatedly.
Types of seizures and the corresponding medications:
- Petit mal seizures usually respond best
to valproic acid or ethosuximide. Clonazepam
or other medications may also be used.
- Grand mal seizures usually respond best
to phenytoin, carbamazepine, valproic acid,
or phenobarbital. Primidone or other medications
may also be used.
- Focal seizures or partial complex seizures
usually respond to phenytoin or carbamazepine.
- Other medications include levitracetam,
gabapentin, gabatril, lamotrigine, oxcarbazepine,
and topiramate.
Follow-up for re-evaluation should occur at
least yearly. Monitoring of plasma drug levels
is important for the continued control of seizures
and the reduction of side effects.
The following factors may cause seizures in a
person with a previously well-controlled seizure
disorder:
- Pregnancy
- Lack of sleep
- Skipping doses of medications
- Use of drugs, medications or alcohol
- Illness
Some patients should carry medical alert jewelry
or cards so that prompt medical treatment can
would obtained if a seizure occurs.
Support
groups
The stress of illness can
often be helped by joining a support group where
members share common experiences and problems.
See epilepsy - support group.
Prognosis
Seizure disorder (epilepsy)
is a chronic, usually lifelong condition. In some
cases, the need for medications may be reduced
or eliminated over time. A seizure-free period
of 4 years may indicate that reduction or elimination
of medications is possible.
Death or permanent brain damage from seizures
is rare but can occur if the seizure is prolonged
or 2 or more seizures occur in proximity (status
epilepticus). Death or brain damage are most often
caused by prolonged lack of breathing and resultant
death of brain tissue (infarction) from lack of
oxygen (ischemia).
Serious injury can occur if a seizure occurs during
driving or when operating dangerous equipment,
so these activities may be restricted for people
with poorly controlled seizure disorders.
Infrequent seizures may not severely restrict
the person’s lifestyle. Work, school, and recreation
do not necessarily nee |
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