Absence seizure

Absence seizures involve brief, sudden lapses of consciousness. They’re more common in children than adults. Someone having an absence seizure may look like he or she is staring into space for a few seconds. 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.

An indication of simple absence seizure is a vacant stare, which may be mistaken for a lapse in attention that lasts 10 to 15 seconds, without any subsequent confusion, headache or drowsiness. 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

Absence seizures generally last 10 to 15 seconds, followed immediately by full recovery. Afterward, there’s no memory of the incident. Some people have dozens of 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.

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 being placed on anti-seizure medication

Seek immediate medical attention:

• If you observe prolonged automatic behaviors — 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

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

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).

Absence seizures are more prevalent in children. Many children gradually outgrow them over months to years. Some children with absence seizures may also experience full seizures (tonic-clonic seizures).

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 10.
• Sex. In general, most seizures are more common in boys, but absence seizures are more common in girls.
• History of febrile seizures. Infants and children who have seizures brought on by fever are at greater risk of absence seizures.
• Family members who have seizures. Nearly half of children with absence seizures have a close relative who has seizures.

While most children outgrow absence seizures, some:

• Have seizures throughout life
• Eventually have full convulsions, such as generalized tonic-clonic seizures

Other complications can include:

• Learning difficulties
• Behavior problems
• Social isolation

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 your child is experiencing,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?
• Are there other possible causes?
• 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 side effects might I expect from treatment?
• Are there alternatives to the treatment you’re suggesting?
• Is there a generic alternative to the medicine you’re prescribing?
• Can my child also develop the grand mal type of seizure?
• How long will my child need to take medication?
• Do I need to restrict activities? Can my child participate in physical activities, such as soccer, football and swimming?
• 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 your child aware of what happened after the seizure?

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.Your child may be asked to breathe rapidly or look at flickering lights, an attempt to provoke a seizure. During a seizure, the pattern on the EEG differs from the normal pattern.
• Brain scans. Tests such as magnetic resonance imaging (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.

Your doctor likely will start at the lowest dose of anti-seizure medication possible and increase the dosage as needed to control the seizures. Most children can 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.
• Valproic acid (Depakene). Because this drug has been associated with higher risk of birth defects in babies, doctors advise women against using it while trying to conceive or during pregnancy. Women who can’t achieve seizure control on other medications should discuss potential risks with their doctors.
• Lamotrigine (Lamictal). Some studies show this drug to be less effective than ethosuximide or valproic acid, but has fewer side effects.

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.

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