Absence seizure

Overview

Absence seizures involve brief, sudden lapses of consciousness. They're more common in children than in adults.

A person having an absence seizure may stare blankly into space for a few seconds. Then the person typically returns quickly to being alert. This type of seizure usually doesn't lead to physical injury. But injury can result during the period when the person loses consciousness. This is particularly true if someone is driving a car or riding a bike when the seizure happens.

Absence seizures usually can be controlled with anti-seizure medicines. Some children who have them also develop other seizures, such as generalized tonic-clonic seizures or myoclonic seizures. Many children outgrow absence seizures in their teens.

Symptoms

A simple absence seizure causes a vacant stare, which may be mistaken for a brief lapse in attention. The seizure lasts about 10 seconds, though it may last as long as 30 seconds. There's no confusion, headache or drowsiness after the seizure.

Symptoms of absence seizures include:

A sudden stop in activity without falling.
Lip smacking.
Eyelid flutters.
Chewing motions.
Finger rubbing.
Small movements of both hands.

Afterward, there's usually no memory of the incident. But if the seizure is longer, the person may be aware of missed time. Some people have many episodes daily. When it happens, it can interfere with school or daily activities.

A child may have absence seizures for some time before an adult notices them. This is because the seizures are so brief. A decline in a child's learning ability may be the first sign of the seizure disorder. Teachers may say the child has trouble paying attention or that a child is often daydreaming.

When to see a doctor

Contact your child's pediatrician:

If you're concerned that your child may be having seizures.
If your child has epilepsy but develops symptoms of a new type of seizure.
If the seizures continue to occur despite taking anti-seizure medicine.

Contact 911 or emergency services in your area:

If you observe prolonged automatic behaviors lasting minutes to hours. This may include activities such as eating or moving without awareness. It also might include prolonged confusion. These are possible symptoms of a condition called status epilepticus.
After any seizure lasting more than five minutes.

Causes

Absence seizures usually have a genetic cause.

In general, seizures occur as a result of a burst of electrical impulses from nerve cells in the brain, called neurons. Neurons typically send electrical and chemical signals across the synapses that connect them.

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 also may have altered levels of the chemical messengers that help the nerve cells communicate with one another. These chemical messengers are called neurotransmitters.

Risk factors

Certain factors are common to children who have absence seizures, including:

Age. Absence seizures are more common in children between the ages of 4 and 14.
Sex. Absence seizures are more common in females.
Family members who have seizures. Nearly a quarter of children with absence seizures have a close relative who has seizures.

Complications

While most children outgrow absence seizures, some:

Must take anti-seizure medicines throughout life.
Eventually have full convulsions, such as generalized tonic-clonic seizures.

Other complications can include:

Learning problems.
Behavior problems.
Social isolation.
Injury during the seizure.

Diagnosis

Your child's health care provider will likely ask for a detailed description of the seizures. The provider also will likely conduct a physical exam. Tests may include:

Electroencephalography (EEG). This painless procedure measures waves of electrical activity in the brain. Brain waves are transmitted to the EEG machine via small metal plates called electrodes attached to the scalp with paste or an elastic cap.

Rapid breathing, known as hyperventilation, during an EEG study can trigger an absence seizure. During a seizure, the pattern on the EEG differs from the typical pattern.
Brain scans. Brain-imaging methods such as MRI can help rule out other problems, such as a stroke or a brain tumor. Brain scans produce detailed images of the brain. Because your child will need to hold still for long periods, talk with your health care provider about the possible use of sedation.

Treatment

Your child's health care provider may start at the lowest dosage of anti-seizure medicine possible. Then the provider may increase the dosage as needed to control the seizures. Children may be able to taper off anti-seizure medicines under a provider's supervision after they've been seizure-free for two years.

Drugs prescribed for absence seizure include:

Ethosuximide (Zarontin). This is the drug most health care providers start with for absence seizures. In most cases, seizures respond well to this drug. Possible side effects include nausea, vomiting, sleepiness, sleep disturbances and hyperactivity.
Valproic acid. Valproic acid treats children who have both absence and tonic-clonic seizures, also known as grand mal seizures. Its side effects include nausea, attention problems, increased appetite and weight gain. Rarely, the medicine can cause inflammation of the pancreas and liver failure.

Females who continue to need medicine into adulthood should discuss potential risks of valproic acid with their health care providers. Valproic acid has been associated with higher risk of birth defects in babies. Providers typically advise not using it during pregnancy or while trying to conceive.
Lamotrigine (Lamictal). Some studies show this drug to be less effective than ethosuximide or valproic acid, but it has fewer side effects. Side effects may include rash and nausea.

Lifestyle and home remedies

Dietary therapy

A ketogenic diet can improve seizure control. This diet is high in fat and low in carbohydrates. It's used only if traditional medicines fail to control the seizures.

This diet isn't easy to maintain, but it's successful at reducing seizures for some people. Variations on a ketogenic diet also might provide benefit. These diets include the glycemic index and modified Atkins diets. Although these diets are less effective at controlling seizures, they aren't as restrictive as the ketogenic diet.

Additional options

Here are other steps that may help with seizure control:

Have your child take medicine correctly. Don't adjust the dosage before talking to your child's health care provider. If you feel your child's medicine should be changed, discuss it with your child's provider.
Encourage enough sleep. Lack of sleep can trigger seizures. Be sure your child gets adequate rest every night.
Have your child wear a medical alert bracelet. This will help emergency personnel know how to treat your child correctly if another seizure occurs.
Ask your child's health care provider about driving or recreation restrictions. Someone with a seizure disorder will have to be seizure-free for a certain length of time before being able to drive. The amount of time required since the last seizure varies from state to state. Don't bathe or swim unless someone else is nearby to help if needed.

Coping and support

If you or your child is living with a seizure disorder, you may feel anxious or stressed about the future. Stress can affect your mental health, so it's important to talk with your health care provider or your child's provider. Seek resources for help.

At home

Your family members can provide much-needed support. Tell them what you know about the seizure disorder. Let them know they can ask you questions, and be open to conversations about their worries. Help them understand the condition by sharing any educational materials or other resources that your primary care provider has given you.

At school

Talk with your child's teachers and coaches about your child's seizure disorder. Explain how it affects your child at school. Discuss what your child might need if a seizure happens at school.

You're not alone

Remember, you don't have to go it alone. Reach out to family and friends. Ask your health care provider about local support groups, or join an online support community. Don't be afraid to ask for help. Having a strong support system is important to living with any medical condition.

Preparing for an appointment

You're likely to start by seeing your child's primary care provider. However, you'll probably be referred to a doctor who specializes in nervous system disorders, known as a neurologist.

Here's some information to help you get ready for the appointment.

What you can do

Write down any symptoms you notice, including any that may seem unrelated to seizures.
Make a list of all medicines, vitamins and supplements you or your child takes.
Write down questions to ask the health care provider.

Preparing a list of questions will help you make the most of your time during the appointment. For absence seizure, some basic questions to ask include:

What's the most likely cause of these symptoms?
What tests are needed? Do these tests require special preparation?
Is this condition temporary or long lasting?
What treatments are available, and which do you recommend?
What are the side effects of the treatment?
Is there a generic alternative to the medicine you're prescribing?
Can my child also develop the grand mal type of seizure?
Are activity restrictions necessary? Are physical activities, such as soccer, football and swimming OK?
Do you have brochures or other printed material I can take? What websites do you recommend?

Don't hesitate to ask any other questions you have.

What to expect from your doctor

Your child's provider is likely to ask you a number of questions, such as:

When did the symptoms begin?
How often have the symptoms occurred?
Can you describe a typical seizure?
How long do the seizures last?
After the seizure, is there awareness of what happened?