Diseases & Conditions

Absence seizure

Absence seizure — also known as petit mal seizure — involves a brief, sudden lapse of conscious activity. Occurring most often in children, an absence seizure may look like the person is merely staring into space for a few seconds.

Compared with other types of epileptic seizures, absence seizures appear mild. But that doesn't mean they can't be dangerous. Children with a history of absence seizure must be supervised carefully while swimming or bathing, because of the danger of drowning. Teens and adults may also be restricted from driving and other potentially hazardous activities.

Absence seizures can usually be controlled with anti-seizure medications. Many children outgrow absence seizures in their teen years, though some may eventually develop grand mal seizures.

Signs of absence seizures include:

• Staring, without unusual movement
• Lip smacking
• Fluttering eyelids
• Chewing
• Hand movements
• Small movements of both arms

Absence seizures last only a few seconds. Full recovery is almost instantaneous. Afterward, there is no confusion, but also no memory of the incident. Some people experience hundreds of these episodes each day, which interferes with their performance at school or work.

Children who are walking or doing other complex tasks during a seizure probably won't fall, though they'll be unaware.

Absence seizures may occur for some time before an adult notices them, because they're so brief. A noticeable decline in a child's learning ability may be the first sign of this disorder. Teachers also may comment about a child's inability to pay attention.

When to see a doctor
Most of the time, no first aid is necessary for an absence seizure. Contact your doctor if it's the first time you've noticed a seizure or if a new type of seizure occurs. People who have absence seizures can also experience other types of seizures.

Seek immediate medical attention if you observe automatic behaviors — performing such activities as eating or moving without being aware of it — or prolonged confusion. These can be a symptom of a dangerous condition called absence status epilepticus. Additionally, any seizure lasting more than five minutes requires immediate medical attention.

Often, no underlying cause can be found for absence seizures. Many children appear to have a genetic predisposition to them. Sometimes hyperventilation can trigger an absence seizure.

In general, seizures are caused by abnormal nerve cell (neuron) activity in the brain. The brain's nerve cells normally communicate with each other by sending electrical and chemical signals across the synapses that connect the cells. In people who have seizures, the brain's usual electrical activity is altered. During an absence seizure, these electrical signals repeat themselves over and over in a three-second pattern.

People who have seizures may also have altered levels of neurotransmitters, which are the chemical messengers that help the nerve cells communicate with one another.

This type of seizure may be more prevalent in children because there are more synapses in a growing brain. Many children gradually outgrow absence seizures over months to years.

Many medications can effectively reduce or eliminate the number of absence seizures. Finding the right medication and dosage can be complex, requiring a period of trial and error. Taking the medications on a regular schedule is crucial to maintaining the proper drug levels in the blood.

Often, the first drug prescribed for absence seizures is ethosuximide (Zarontin). However, other medications, such as valproic acid (Depakene) and lamotrigine (Lamictal), also are effective at controlling seizures. Your doctor will likely start at the lowest dose of medication possible, and increase the dosage as needed to control the seizures. Most children can discontinue anti-seizure medications, under a doctor's supervision, after they've been seizure-free for two years.

Female adults who need treatment for absence seizures are advised against using valproic acid while trying to conceive or during pregnancy, because the drug has been associated with higher risk of serious complications for the baby. Women who can't achieve seizure control on any other medication need to speak with their doctors about the potential risks.

A person with absence seizures may elect to wear a medical bracelet for identification for emergency medical reasons. The bracelet should state whom to contact in an emergency and what medications you use. It's also a good idea to let teachers, coaches and child care workers know about the seizures and tell them what to do in an emergency.