Absence seizure (petit mal seizure)

Definition

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.

Symptoms

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.

Causes

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.

Complications

While most children outgrow absence seizures, some people continue to have these types of seizures throughout their lives. In some cases, people who have absence seizures eventually begin experiencing full convulsions (grand mal or generalized tonic-clonic seizures).

Other complications can include:

• Learning difficulties
• Absence status epilepticus, a condition in which seizure behavior lasts longer than a few minutes

Preparing for your appointment

You're likely to start by first seeing your family doctor or a general practitioner. However, you or your child will probably be referred to a doctor who specializes in nervous system disorders (neurologist).

Because appointments can be brief, and there's often a lot of ground to cover, it's a good idea to be well prepared for your appointment. Here's some information to help you get ready for your appointment, and what to expect from your doctor.

What you can do

• Write down any symptoms you or your child are experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Make a list of all medications, as well as any vitamins or supplements, that you or your child takes.
• Write down questions to ask the doctor.

Your time with your doctor is limited, so preparing a list of questions ahead of time will help you make the most of your time together. List your questions from most important to least important in case time runs out. For absence seizure, some basic questions to ask your doctor include:

• What's the most likely cause of these symptoms?
• Are there other possible causes?
• What kinds of tests are needed? Do these tests require any special preparation?
• Is this condition temporary or long lasting?
• What treatments are available, and which do you recommend?
• What types of side effects can I expect from treatment?
• Are there any alternatives to the primary approach that you're suggesting?
• Are there any activity restrictions that need to be followed?
• Is there a generic alternative to the medicine you're prescribing?
• Are there any brochures or other printed material that I can take home with me? What Web sites do you recommend?
• Can my child also develop the grand mal type of seizure?
• How long will my child need to take medication?
• Can my child participate in physical activities, such as soccer, football and swimming?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time that you don't understand something.

What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:

• When did you or your child first begin experiencing symptoms?
• How often have the symptoms occurred?
• Can you describe a typical seizure?
• How long do the seizures last?
• Are you or your child aware of what happened?

Tests and diagnosis

Some children experience episodes that resemble absence seizures, but aren't truly seizures. Such episodes can usually be interrupted by calling the child's name or by touching his or her shoulder. True absence seizures, on the other hand, can't be interrupted by voice or touch. They also tend to occur right in the middle of a child's conversation or physical activity.

For a proper diagnosis, your doctor will ask for a detailed description of the seizures. Blood tests can help rule out other potential causes of seizures, such as a chemical imbalance or the presence of toxic substances. Other tests may include:

• Electroencephalography (EEG). This painless procedure measures the waves of electrical activity in the brain. The brain waves are transmitted to the EEG machine via small electrodes attached to the scalp with paste or an elastic cap. Your child may be asked to hyperventilate or look at flickering lights, in an attempt to provoke a seizure. During a seizure, there's a difference in the normal pattern seen on the EEG.
• Brain scans. Tests such as magnetic resonance imaging (MRI) can produce very detailed images of the brain, which can help rule out other types of problems such as a stroke or a brain tumor. This test is not painful, but your child will need to hold very still for long periods of time. Talk with your doctor about the possible use of sedation, especially for young children.

Treatments and drugs

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.

Lifestyle and home remedies

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.