Epilepsy Health Article

Definition

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

Alternative Names

Seizure disorder

Causes, incidence, and risk factors

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