Epilepsy
Definition
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Epilepsy is a brain disorder involving repeated spontaneous seizures of any type.
Causes
Seizures ("fits," convulsions) are episodes of disturbed brain function that cause changes in attention or behavior. They are caused by abnormally excited electrical signals in the brain.
Sometimes seizures are related to a temporary condition, such as exposure to drugs, withdrawal from certain drugs, or abnormal levels of sodium or glucose in the blood. In the repeated seizures do not happen again once the underlying problem is corrected, the person does NOT have epilepsy.
In other cases, injury to the brain (for example, stroke or head injury) causes brain tissue to be abnormally excitable. In some people, an inherited abnormality affects nerve cells in the brain, which leads to seizures. In these cases, the seizures happen spontaneously, without an immediate cause. This IS epilepsy.
Some seizures are idiopathic, which means the cause cannot be identified. These seizures usually begin between ages 5 and 20, but they can happen at any age. People with this condition have no other neurological problems, but sometimes have a family history of seizures or epilepsy.
Disorders affecting the blood vessels, such as stroke and TIA, are the most common cause of seizures after age 60. Illnesses that cause the brain to deteriorate and dementia such as Alzheimer's diesease, can also lead to seizures.
Some of the more common causes of epilepsy include:
- Problems during the development of the baby in the womb.
- Brain injury
- Early seizures (within 2 weeks of injury) do not necessarily mean that chronic (ongoing) seizures (epilepsy) will develop
- Most common in young adults
- Seizures usually begin within 2 years after the injury
- Genetic conditions present at birth.
- Infections
- Acute severe infections of any part of the body
- Brain abscess
- Brain infections like meningitis and encephalitis
- Chronic infections (such as neurosyphilis)
- Complications of AIDS or other immune disorders
- May affect people of all ages
- May be a reversible cause of seizures (epilepsy may stop)
- Injuries near the time of birth (seizures usually begin in infancy or early childhood)
- Metabolic abnormalities (problems with body chemistry) may affect people of any age and may be a result of
- Kidney failure, uremia (toxic accumulation of wastes)
- Liver Failure
- Nutritional deficiencies
- Phenylketonuria (PKU) -- can cause seizures in infants
- Other metabolic diseases, such as inborn error of metabolism
- Tumors and brain lesions (such as hematomas or abnormal blood vessels)
- May affect any age but are more common after age 30
- May lead to generalized tonic-clonic seizures
- Partial (focal) seizures most common to start with
About 0.5% of the population has epilepsy. Approximately 1.5-5.0% of the population may have a seizure in their lifetime. Epilepsy can affect people of any age.
Risk factors include a family history of epilepsy, head injury, or other condition that causes damage to the brain.
Some factors may present a risk for more seizures in a person with a previously well-controlled seizure disorder:
- Certain prescribed medications
- Emotional stress
- Illness, especially infection
- Lack of sleep
- Pregnancy
- Skipping doses of epilepsy medications
- Use of alcohol or other recreational drugs
Symptoms
The severity of symptoms can vary greatly, from simple staring spells to loss of consciousness and violent convulsions. For most people, each seizure is similar, while some people have many different types of seizures that cause different symptoms each time. The type of seizure a person has depends on a variety of things, such as the part of the brain affected and the underlying cause of the seizure.
An aura consisting of a strange sensation (such as tingling, smelling an odor that isn't actually there, or emotional changes) occurs in some people prior to each seizure. Seizures may occur repeatedly without explanation.
Note: Disorders that may cause symptoms resembling seizures include fainting, transient ischemic attacks (TIAs) or stroke, rage or panic attacks, migraine headaches, sleep disturbances, and other disorders that cause loss of consciousness.
SYMPTOMS OF GENERALIZED SEIZURES
Generalized seizures affect all or most of the brain. They include absence seizures (also called petit mal seizures) and tonic-clonic seizures (also called grand 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
- Can happen over and over
- Occurs most often during childhood
- Decreased learning (child often thought to be day-dreaming)
- Affects a major part of the body
- Breathing stops temporarily, followed by sighing
- Confusion following the seizure, lasting minutes to hours
- Incontinence of urine (loss of bladder control)
- Loss of consciousness
- Rigid and stiff
- Tongue or cheek biting
- Weakness following the seizure (Todd's paralysis)
- Whole body, violent muscle contractions
SYMPTOMS OF PARTIAL SEIZURES (SIMPLE AND COMPLEX)
Partial seizures may be complex or simple. Partial seizures affect only a portion of the brain.
Symptoms of simple partial (focal) seizures may include:
- Abnormal sensations (feelings)
- Dilated pupils
- Feeling as if you've been in this situation before (deja vu) or never been in this situation before (jamais vu)
- Hallucinations
- Muscle contractions of a specific body part
- Nausea
- Skin flushing
- Sweating
Symptoms of partial complex seizures may include:
- Any of the above symptoms, along with altered consciousness or memory
- Automatism (automatic performance of complex behaviors without conscious awareness)
- Changes in personality or alertness, with confusion
Exams and Tests
To be diagnosed with epilepsy and seizure disorders, the person must have had spontaneous, recurrent seizures with no immediate cause. A physical examination (including a detailed neuromuscular examination) may be normal, or it may show abnormal brain function related to specific areas of the brain.
An electroencephalograph (EEG), which is a reading of the electrical activity in the brain, may show various types of seizures. In some cases it may show the location of the abnormal part of the brain where the seizures start. EEGs can often be normal in between seizures, so it may be necessary to do prolonged EEG monitoring.
Various blood tests and other tests to rule out temporary and reversible causes of seizures, may include:
- Blood chemistry
- Blood sugar
- CBC (complete blood count)
- CSF (cerebrospinal fluid) analysis
- Kidney function tests
- Liver function tests
- Tests for infectious diseases
Tests for the cause and location of the problem may include:
- EEG
- Head CT or MRI scan
- Lumbar puncture (spinal tap)
Treatment
For treatment of seizures, please see Seizures - first aid.
If an underlying cause for recurrent seizures (such as infection) has been identified and treated, seizures may stop. Treatment may include surgery to remove a tumor, an abnormal or bleeding blood vessel, or other brain problems.
Medication to prevent seizures, called anti-convulsants, may reduce the number of future seizures. These drugs are taken by mouth. The type of medicine you take depends on what type of seizures you are having. The dosage may need to be adjusted from time to time.
Some seizure types respond well to one medication and may respond poorly (or even be made worse) by others. Some medications need to be monitored for side effects and blood levels.
It is very important that you take seizure drugs on time and at the correct dose. Most people taking these drugs need regular checkups and regular blood tests to make sure they are receiving the correct dosage. No one should stop taking or change seizure drugs without talking with their doctor first.
Epilepsy that does not get better after two or three seizure drugs have been tried is called "medically refractory epilepsy." Some people with this type of epilepsy may benefit from brain surgery to remove the abnormal brain cells that are causing the seizures. Others may be helped by a vagal nerve stimulator. This is a device that is implanted in the chest (similar to a heart pacemaker). This stimulator can help reduce the number of seizures, but rarely stops the seizures completely.
Sometimes, children are placed on a special diet to help prevent seizures. The most popular one is the ketogenic diet. A diet low in carbohydrates, such as the Atkin's diet, may also be helpful in some adults.
People with epilepsy should wear medical alert jewelry so that prompt medical treatment can be obtained if a seizure occurs.
Support Groups
The stress caused by having seizures (or being a caretaker of someone with seizures) can often be helped by joining a support group. In these groups, members share common experiences and problems. See epilepsy - support group.
In addition to groups that meet face-to-face, there are many discussion groups and bulletin boards on the Internet where people with epilepsy can find support.
Outlook (Prognosis)
Some people with certain types of seizures may be able to reduce or completely stop their seizure medicines after having no seizures for several years. Certain types of childhood epilepsy goes away or improves with age -- usually in the late teens or 20s.
For some people, epilepsy may be lifelong condition. In these cases, the seizure drugs need to be continued.
Death or permanent brain damage from seizures is rare, but can occur if the seizure is prolonged or two or more seizures occur close together (status epilepticus). Death or brain damage are most often caused by prolonged lack of breathing, which causes brain tissue to die from lack of oxygen. There are some cases of sudden, unexplained death in patients with epilepsy.
Serious injury can occur if a seizure occurs during driving or when operating dangerous equipment. For this reason, people with epilepsy whose seizures are not under good control may not be able to do these activities.
People who have infrequent seizures may not have any severe restrictions on their lifestyle.
Possible Complications
- Difficulty learning
- Inhaling fluid into the lungs, which causes aspiration pneumonia
- Injury from falls, bumps, or self-inflicted bites during a seizure
- Injury from having a seizure while driving or operating machinery
- Many epilepsy medications cause birth defects -- women wishing to become pregnant should alert their doctor in advance in order to adjust medications
- Permanent brain damage (stroke or other damage)
- Prolonged seizures or numerous seizures without complete recovery between them (status epilepticus)
- Side effects of medications
When to Contact a Medical Professional
Call your local emergency number (911) if this the first time a person has had a seizure or a seizure is occurring in someone without a medical ID bracelet (instructions explaining what to do). In the case of someone who has had seizures before, call the ambulance for any of these emergency situations:
- This is a longer seizure than the person normally has, or an unusual number of seizures for the person
- Repeated seizures over a few minutes
- Repeated seizures where consciousness or normal behavior is not regained between them (status epilepticus)
Call your health care provider if any new symptoms occur, including possible side effects of medications (drowsiness, restlessness, confusion, sedation, or others), nausea/vomiting, rash, loss of hair, tremors or abnormal movements, or problems with coordination.
Prevention
Generally, there is no known way to prevent epilepsy. However, proper diet and sleep, and staying away from illegal drugs and alcohol, may decrease the likelihood of triggering seizures in people with epilepsy.
Reduce the risk of head injury by wearing helmets during risky activities; this can help lessen the chance of developing epilepsy.
Foldvary-Schaefer N, Wyllie E. Epilepsy. In: Goetz, CG, ed. Textbook of Clinical Neurology. 3rd ed. Philadelphia, PA: Saunders Elsevier; 2007: chap 52.
Krumholz A, Wiebe S, Gronseth G, et al. Practice Parameter: evaluating an apparent unprovoked first seizure in adults (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology. 2007;69(21):1996-2007.
Spencer SS. Seizures and epilepsy. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, PA: Saunders Elsevier; 2007: chap 426.
Tomson T, Hiilesmaa V. Epilepsy in Pregnancy. BMJ. 2007;335(7623):769-73.
Reviewed By: Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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