Absence seizure

Date Updated: 02/24/2021

Overview

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

Someone having an absence seizure may look like he or she is staring blankly into space for a few seconds. Then, there is a quick return to a normal level of alertness. This type of seizure usually doesn't lead to physical injury.

Absence seizures usually can be controlled with anti-seizure medications. Some children who have them also develop other seizures. Many children outgrow absence seizures in their teens.

Symptoms

An indication of simple absence seizure is a vacant stare, which may be mistaken for a lapse in attention that lasts about 10 seconds, though it may last as long as 20 seconds, without any confusion, headache or drowsiness afterward. Signs and symptoms of absence seizures include:

Sudden stop in motion without falling
Lip smacking
Eyelid flutters
Chewing motions
Finger rubbing
Small movements of both hands

Afterward, there's no memory of the incident. Some people have many episodes daily, which interfere with school or daily activities.

A child may have absence seizures for some time before an adult notices the seizures, because they're so brief. A decline in a child's learning ability may be the first sign of this disorder. Teachers may comment about a child's inability to pay attention or that a child is often daydreaming.

When to see a doctor

Contact your doctor:

The first time you notice a seizure
If this is a new type of seizure
If the seizures continue to occur despite taking anti-seizure medication

Contact 911 or emergency services in your area:

If you observe prolonged automatic behaviors lasting minutes to hours — activities such as eating or moving without awareness — or prolonged confusion, possible symptoms of a condition called absence status epilepticus
After any seizure lasting more than five minutes

Causes

Many children appear to have a genetic predisposition to absence seizures.

In general, seizures are caused by abnormal electrical impulses from nerve cells (neurons) in the brain. The brain's nerve cells normally 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 may also have altered levels of the chemical messengers that help the nerve cells communicate with one another (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 girls.
Family members who have seizures. Nearly half of children with absence seizures have a close relative who has seizures.

Complications

While most children outgrow absence seizures, some:

Must take anti-seizure medications throughout life to prevent seizures
Eventually have full convulsions, such as generalized tonic-clonic seizures

Other complications can include:

Learning difficulties
Behavior problems
Social isolation

Diagnosis

Your doctor will ask for a detailed description of the seizures and 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 electrodes attached to the scalp with paste or an elastic cap.

Rapid breathing (hyperventilation) during an EEG study can trigger an absence seizure. During a seizure, the pattern on the EEG differs from the normal pattern.
Brain scans. In absence seizures, brain-imaging studies, such as magnetic resonance imaging (MRI), will be normal. But tests such as MRI can produce detailed images of the brain, which can help rule out other problems, such as a stroke or a brain tumor. Because your child will need to hold still for long periods, talk with your doctor about the possible use of sedation.

Treatment

Your doctor likely will start at the lowest dose of anti-seizure medication possible and increase the dosage as needed to control the seizures. Children may be able to taper off anti-seizure medications, under a doctor's supervision, after they've been seizure-free for two years.

Drugs prescribed for absence seizure include:

Ethosuximide (Zarontin). This is the drug most doctors start with for absence seizures. In most cases, seizures respond well to this drug. Possible side effects include nausea, vomiting, sleepiness, trouble sleeping, hyperactivity.
Valproic acid (Depakene). Girls who continue to need medication into adulthood should discuss potential risks of valproic acid with their doctors. Valproic acid has been associated with higher risk of birth defects in babies, and doctors advise women against using it during pregnancy or while trying to conceive.

Doctors may recommend the use of valproic acid in children who have both absence and grand mal (tonic-clonic) seizures.
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

Following a diet that's high in fat and low in carbohydrates, known as a ketogenic diet, can improve seizure control. This is used only if traditional medications fail to control the seizures.

This diet isn't easy to maintain, but is successful at reducing seizures for some people. Variations on a high-fat, low-carbohydrate diet, such as the glycemic index and modified Atkins diets, though less effective, aren't as restrictive as the ketogenic diet and may also provide benefit.

Additional options

Here are other steps you might take to help with seizure control:

Take medication correctly. Don't adjust the dosage before talking to your doctor. If you feel your medication should be changed, discuss it with your doctor.
Get enough sleep. Lack of sleep can trigger seizures. Be sure to get adequate rest every night.
Wear a medical alert bracelet. This will help emergency personnel know how to treat you correctly if you have another seizure.
Ask your doctor about driving or recreation restrictions. Someone with a seizure disorder will have to be seizure-free for reasonable lengths of time (intervals vary from state to state) before being able to drive. Don't bathe or swim unless someone else is nearby to help if needed.

Coping and support

If you're living with a seizure disorder, you may feel anxious or stressed about what your future holds. Stress can affect your mental health, so it's important to talk with your doctor about your feelings and 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 doctor has given you.

At school

Talk with your child's teachers and coaches about your child's seizure disorder and how it affects your child at school. Discuss what your child might need from them 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 doctor 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 family doctor or a general practitioner. However, you'll probably be referred to a doctor who specializes in nervous system disorders (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 medications, vitamins and supplements you or your child takes.
Write down questions to ask the doctor.

Preparing a list of questions will help you make the most of your time with your doctor. For absence seizure, some basic questions to ask your doctor 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 doctor 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?
Is there awareness of what happened after the seizure?