Absence Seizures

Absence seizures are seizures that generally last just a few seconds, and are characterized by a blank or "absent" stare. They're also sometimes called petit mal seizures. Absence seizures are most common in children and typically don't cause any long-term problems.

Absence seizures usually occur when a child is 4 to 12 years old. Your child may have 10, 50, or even 100 absence seizures in a given day. Sometimes absence seizures can happen so subtly and so quickly that you never even notice them.

Seizures can occur for many different reasons, and not all seizures are caused by epilepsy. Often, doctors don't know why seizures happen.

Facts about absence seizures

An irregularity in the brain's normal electrical activity causes absence seizures. Most absence seizures are less than 15 seconds long. It's rare for an absence seizure to last longer than 15 minutes. Absence seizures strike suddenly without any warning signs.

It's uncommon for an absence seizure to continue into adulthood, but it's possible to have an absence seizure at any age.

Absence seizures may occur along with other types of seizures, which can result in muscle jerking, twitching, and shaking.

Although most children who have typical absence seizures are otherwise normal, absence seizures can hinder learning and affect concentration at school, so treatment must be prompt.

Because some absence seizures may be accompanied by twitching of the eyelids and facial muscles, they may be mistaken for another type of seizure, known as complex partial seizures. But unlike complex partial seizures, absence seizures don't begin with an aura, or premonition that a seizure is coming. They also don't last as long, tend to end suddenly, and don’t cause a period of confusion after the seizure. Getting the right diagnosis is essential for effective and appropriate treatment of absence seizures.

Types of absence seizures

There are many different kinds of seizures but only one type of absence seizures.

Signs and symptoms of absence seizures

The easiest way to identify an absence seizure is to look for a vacant stare that lasts for a few seconds. People in the midst of having an absence seizure don't speak, listen, or appear to understand. An absence seizure doesn't typically cause you to fall down. You could be in the middle of making dinner, walking across the room, or typing an e-mail when you freeze, then suddenly snap out of it, and continue as you were before the seizure.

These are other possible symptoms of an absence seizure:

  • Being very still

  • Smacking the lips or making a chewing motion with the mouth

  • Fluttering the eyelids

  • Stopping activity (suddenly not talking or moving)

  • Suddenly returning to activity when the seizure ends

If you or your child experiences jerking motions, it may be a sign of another type of seizure taking place along with the absence seizure.

Diagnosis

You may experience absence seizures repeatedly for years before heading to the doctor for a diagnosis. You may think of or call these symptoms your "spells," without thinking of them as a medical problem or a seizure.

An electroencephalogram is a test most often used to diagnose absence seizures. This test records the brain's electrical activity and spots any abnormalities that could indicate an absence seizure.

These tests also can help to diagnose absence seizures or rule out other conditions:

  • Blood tests

  • Tests of the kidneys and liver

  • CT or MRI scans

  • Spinal tap to test the cerebrospinal fluid 

Treating absence seizures

Absence seizures can affect your ability to perform at work or school, so it's a good idea to see your doctor about treatment.

Absence seizures can be treated with a number of different medications:

  • Valproic acid

  • Acetazolamide

  • Lamotrigine

  • Clonazepam

  • Ethosuximide

Most antiepileptic drugs aren’t effective in treating absence seizures. Many people who suffer from absence seizures also have generalized seizures and so would need to take one or more of the medications listed above. At this time, only two drugs have approval from the FDA to treat absence seizures: ethosuximide and valproic acid.

Managing absence seizures

Medication can help manage absence seizures. Making lifestyle changes can also help to keep them under control. If you have trouble managing your absence seizures, you may want to work more closely with your doctor to find a better way to treat them.

If you continue to have absence seizures, it may not be safe for you to drive.

Preventing absence seizures

Taking your medications exactly as your doctor prescribed is one of the best ways to manage absence seizures. But you can also make some changes in your life to help prevent absence seizures from happening:

  • Get plenty of sleep each night.

  • Find ways to manage your stress.

  • Eat a healthy diet.

  • Exercise regularly.

Key points to remember

Absence seizures are easy to miss, but tests and an evaluation of symptoms can diagnose them. Doctors can usually help find the right mix of medications and lifestyle changes to manage absence seizures. Without treatment, your school performance, work, and relationships can suffer.