Epilepsy

Definition

Epilepsy is a brain disorder involving repeated seizures of any type.

Alternative Names

Causes

Seizures ("fits") are episodes of disturbed brain function that cause changes in attention or behavior. They are caused by abnormal 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 such cases, repeated seizures may not recur once the underlying problem is corrected.

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.

Some seizures are idiopathic, which means the cause can not be identified. Such seizures usually being between age 5 and 20, but can occur at any age. People with this condition have no other neurological problems, but often 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. Degenerative disorders such as senile dementia Alzheimer type can also lead to seizures.

Some of the more common causes of seizures include:

• Developmental problems, genetic conditions present at birth, or injuries near birth (seizures usually begin in infancy or early childhood)
• Metabolic abnormalities may affect people of any age and may be a result of
  • Diabetes complications
  • Electrolyte imbalances
  • Kidney failure, uremia (toxic accumulation of wastes)
  • Nutritional deficiencies
  • Phenylketonuria (PKU) -- can cause seizures in infants
  • Other metabolic diseases, such as inborn error of metabolism
  • Use of cocaine, amphetamines, alcohol, or certain other recreational drugs
  • Withdrawal from alcohol
  • Withdrawal from drugs, particularly barbiturates and benzodiazepines
• Brain injury
  • Most common in young adults
  • Seizures usually begin within 2 years after the injury
  • Early seizures (within 2 weeks of injury) do not necessarily mean that chronic (ongoing) seizures (epilepsy) will develop
• Tumors and brain lesions (such as hematomas)
  • May affect any age but are more common after age 30
  • Partial (focal) seizures most common to start with
  • May lead to generalized tonic-clonic seizures
• Infections
  • May affect people of all ages
  • May be a reversible cause of seizures
  • Brain infections like meningitis and encephalitis can produce seizures
  • Brain abscess
  • Acute severe infections of any part of the body
  • Chronic infections (such as neurosyphilis)
  • Complications of AIDS or other immune disorders

Seizure disorders affect about 0.5% of the population. 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.

The following factors may present a risk for worsening of seizures in a person with a previously well-controlled seizure disorder:

• Pregnancy
• Lack of sleep
• Skipping doses of epilepsy medications
• Use of alcohol or other recreational drugs
• Certain prescribed medications
• Illness

Symptoms

The severity of symptoms can vary greatly, from simple staring spells to loss of consciousness and violent convulsions. For many patients, the event is the same thing over and over, 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 many 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, smell, 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 transient ischemic attacks (TIAs), rage or panic attacks, and other disorders that cause loss of consciousness.

SYMPTOMS OF GENERALIZED SEIZURES

Generalized seizures affect all or most of the brain. They include petit mal and grand mal 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 day-dreaming)

• Whole body, violent muscle contractions
• Rigid and stiff
• Affects a major part of the body
• Loss of consciousness
• Breathing stops temporarily, followed by sighing
• Incontinence of urine
• Tongue or cheek biting
• Confusion following the seizure
• Weakness following the seizure (Todd's paralysis)

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:

• Muscle contractions of a specific body part
• Abnormal sensations
• Nausea
• Sweating
• Skin flushing
• Dilated pupils

Symptoms of partial complex seizures may include:

• Automatism (automatic performance of complex behaviors without conscious awareness)
• Abnormal sensations
• Nausea
• Sweating
• Skin flushing
• Dilated pupils
• Recalled or inappropriate emotions
• Changes in personality or alertness
• May or may not lose consciousness
• Problems with smell or taste -- if the epilepsy is focused in the temporal lobe of the brain

Exams and Tests

The diagnosis of epilepsy and seizure disorders requires a history of recurrent seizures of any type. 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), a reading of the electrical activity in the brain, may confirm the presence of various types of seizures. It may, in some cases, indicate the location of the lesion causing the seizure. EEGs can often be normal in between seizures, so it may be necessary to do prolonged EEG monitoring.

Tests may include various blood tests to rule out other temporary and reversible causes of seizures, including:

• CBC
• Blood chemistry
• Blood glucose
• Liver function tests
• Kidney function tests
• Tests for infectious diseases
• CSF (cerebrospinal fluid) analysis

Tests for the cause and location of the problem may include:

• 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 repair a tumors or brain lesions.

Anti-convulsants taken by mouth may reduce the number of future seizures. How well medicine works depends on each individual's response to the drug. The type of medicine used depends on seizure type, and 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.

Epilepsy that does not respond to the use of several medications is called refractory epilepsy. Certain 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 with a vagal nerve stimulator, which is implanted in the chest. This stimulator can help reduce the number of seizures.

Sometimes, children are placed on a special diet to help prevent seizures. The most one is the ketogenic diet.

Patients 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.

Outlook (Prognosis)

Epilepsy may be a chronic, lifelong condition. In some cases, the need for medications may be reduced or eliminated over time. Certain types of childhood epilepsy resolve or improve with age. 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 close together (status epilepticus). Death or brain damage are most often caused by prolonged lack of breathing and resultant death of brain tissue 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, 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 need to be restricted.

Possible Complications

• Prolonged seizures or numerous seizures without complete recovery between them (status epilepticus)
• Injury from falls, bumps, or self-inflicted bites
• Injury from having a seizure while driving or operating machinery
• Inhaling fluid into the lungs and subsequent aspiration pneumonia
• Permanent brain damage (stroke or other damage)
• Difficulty with learning
• Side effects of medications
• Many anti-epileptic medications cause birth defects -- women wishing to become pregnant should alert their doctor in advance in order to adjust 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

Prevention

Generally, there is no known way to prevent epilepsy. However, adequate diet and sleep, and abstinence from drugs and alcohol, may decrease the likelihood of precipitating a seizure 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.