Causes of Epilepsy

The causes vary according to the age of onset. Seizures are classified as symptomatic, in which the cause is known, or idiopathic, in which the cause is unknown. In approximately 60 to 75 percent of epilepsy cases, no specific cause of the seizures can be identified. In the remaining 25 to 40 percent, some of the causes include:

• Genetic causes

• Birth Injury (e.g. lack of oxygen to the brain at birth)

• Developmental disorder (e.g. brain damage to the fetus during pregnancy)

• Brain trauma (e.g. from car accidents or sports injuries)

• Infection (e.g. meningitis, encephalitis, AIDS)

• Brain tumour

• Stroke

• Cerebral degenerative disorder (e.g. those associated with Alzheimer’s Disease)

• Substance Abuse

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Some types of epilepsy have a genetic basis. In certain epilepsies, one or more inherited genes may result in the disorder.

In other cases, an inherited neurologic disorder than involves structural or chemical abnormalities in the brain can increase the risk of seizures and lead to epilepsy.

Another factor associated with a genetic cause of epilepsy is an inherited susceptibility to seizures. Each individual has a seizure threshold that determines the level at which the brain will have a seizure. Some individuals inherit a lower threshold or lower resistance to seizures resulting in a greater risk of having seizures.

The risk of a child having unprovoked seizures is one to two percent in the general population and approximately six percent if a parent has epilepsy.

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Types of Seizures

Generalized Tonic Clonic (formerly known as Grand Mal)

Tonic clonic seizures are characterized by a fall and rigidity. It is followed by shallow breathing or temporarily suspended breathing, bluish skin and possible loss of bladder or bowel control. The seizure generally lasts a couple of minutes. There may be some confusion and/or fatigue, followed by a return to full consciousness.

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Absence (formerly known as Petit Mal)

Absence seizures are most common in children. It begins with a blank stare, only lasting a few seconds. The absence seizure may also be accompanied by rapid blinking or chewing movements of the mouth. The child or adult may not be aware of what’s going on during the seizure but quickly returns to full awareness once it has stopped. This type of seizure should not be mistaken for daydreaming or a lack of attention.

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Focal Seizures with Impaired Awareness (formerly known as Complex Partial)

Focal seizures with impaired awareness usually start with a blank stare, followed by repetitive physical activity. The person appears dazed and may make sounds like muffled speech. While the seizure usually lasts only a few minutes, post-seizure confusion can last substantially longer. This condition should not be mistaken as intoxication.

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Focal Aware Seizures

Focal aware seizures begin with movement in one area of the body – such as the arm, leg, or face. It cannot be stopped, but the patient stays awake and is aware of what is happening. Spasms may proceed from one area of the body to another and sometimes spread to become a convulsive seizure.

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