Epilepsy is a disorder involving repeated seizures of any type. Seizures ("fits") are episodes of disturbed brain function that cause changes in attention and/or behavior. They are caused by abnormal electrical excitation 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 (e.g., 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 some cases, no cause can be identified.

Some of the more common causes of seizures include:

• Idiopathic (no identifiable cause)
  • usually begin between age 5 and 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 people of any age
  • 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
  • may affect any age, but most common in young adults
  • most likely to occur 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 (ongoing) 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 (such as stroke and TIA)
  • 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 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

The severity of symptoms can vary greatly from simple staring spells to loss of consciousness and violent convulsions. For many patients, the event is stereotyped (the same thing over and over) while some patients have many different types of seizures that cause different symptoms each time.

The type of seizure a person experiences depends on a variety of factors, such as the part of the brain affected, the cause, and individual response.

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.

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 portion of the body
• Loss of consciousness
• Breathing stops temporarily, then "sighing"
• Incontinence of urine
• Tongue or cheek biting
• Confusion following the seizure
• Weakness following the seizure (Todd's paralysis)

SYMPTOMS OF PARTIAL SEIZURES

Partial seizures affect only a portion of the brain.

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

• Automatism (automatic performance of complex behaviors without conscious awareness)
• 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 the epilepsy is focused in the temporal lobe 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:

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

• A head CT or MRI scan
• A lumbar puncture (spinal tap)

For treatment of seizures, please see Seizures - first aid.

If an underlying cause for recurrent seizures (such as infection) has been identified, the cause should be treated, and this may stop the occurrence of further seizures. This may include surgical repair of tumors or brain lesions, or other treatments.

Oral anti-convulsants may reduce the number of future seizures. Response is individual, and the medication used and dosage may have to be adjusted repeatedly. The type of medicine used depends on the seizure type, as some seizure types respond well to one medication and may respond poorly (or even be made worse) by others.

The need for follow-up depends on the seizure type and medications used. Some medications need to be monitored for side effects and blood levels.

For some patients, the use of several medications may still be inadequate. This is called refractory epilepsy. Some such people may benefit from brain surgery to remove the abnormal brain cells that are causing the seizures. For others, a vagal nerve stimulator is implanted in the chest, which can help reduce the number of seizures.

• 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

Call your local emergency number (911) if this the first time a person has had a seizure or a seizure is occuring 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.

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.