Overview of Atypical Absence Seizures

What is an atypical absence seizure?

An absence seizure causes a temporary lapse in your awareness that may resemble daydreaming or “spacing out.” They’re a type of generalized onset seizure, meaning they affect both sides of your brain at the same time.

Absence seizures tend to occur during childhood. Some people continue to have them throughout life or also experience other types of seizures as they get older.

An atypical absence seizure has features not typically observed in most absence seizures. They tend to:

  • last longer
  • start and stop more gradually
  • be harder to manage
  • persist throughout your life

Atypical absence seizures also usually begin during childhood. But they are generally part of a developmental disorder or a more extensive epilepsy syndrome.

Atypical absence seizures are reported in up to 60 percent of people with Lennox-Gastaut syndrome. They also occur in other genetic generalized epilepsies such as childhood absence epilepsy, juvenile absence epilepsy, and juvenile myoclonic epilepsy.

Symptoms of atypical absence seizures in adults and children

Atypical absence seizures can be difficult to recognize. A person experiencing a seizure may appear like they’re daydreaming and symptoms tend to appear gradually. Absence seizures typically last 15 to 30 seconds and sometimes longer.

Usual features of an atypical absence seizure include:

  • the person may stare blankly but may be able to respond in a limited way
  • they may blink their eyes, make chewing movements, or move their lips
  • they may make small movements with their hands
  • they won’t be aware of what’s going on around them and may not hear somebody talking to them.
  • the person may seem out of character, confused, or agitatated

What is atypical absence epilepsy?

Atypical absence epilepsy is when a person experiences recurrent atypical absence seizures. Atypical absence seizures, however, can also be a feature of several types of epilepsy.

Aftereffects of an atypical absence seizure

After an atypical absence seizure, a person will usually be awake but won’t have any memory of the seizure. They may feel tired or confused, especially if they had multiple seizures.

First aid isn’t needed for a single atypical absence seizure but may be required for if they also have other types, such as a clonic or atonic seizure.

Atypical absence seizure causes

The exact cause of atypical absence seizures remains unclear, but researchers think certain genes may cause changes in the brain that make some people more likely to experience them.

Situations that may trigger atypical absence seizures include:

  • withdrawal from benzodiazepines,
  • alcohol
    • , or other CNS drugs
  • some medications like isoniazid and antipsychotics
    • alcohol
  • poor sleep
  • not following prescribed treatment

Who is at risk for atypical absence seizures?

Atypical absence seizures generally start in early childhood and usually continue into adulthood.

Absence seizures in general are slightly more common in females and tend to primarily affect children who’ve had a close relative who also had seizures. People with absence seizures typically also have other types of seizures, such as atonic, tonic, or myoclonic.

What to do if you or someone else is having an atypical absence seizure?

Most of the time, people having atypical absence seizures aren’t in danger of hurting themselves, and their symptoms usually only last seconds. Normally, no particular intervention is needed, but it’s a good idea to stay with the person until their seizure is finished.

When to see a doctor

Seek medical treatment if you believe a person is experiencing a seizure for the first time, if they’re experiencing a new type of seizure, or if they become unconscious, develop injuries, or have trouble breathing.

You should call 911 or go to the nearest emergency room if:

  • the person having the seizure is pregnant or has diabetes
  • the seizure occurs in the water
  • it lasts more than 5 minutes
  • they remain unconscious or stops breathing after the seizure
  • they develop a high fever
  • they gets injured
  • they have another seizure before regaining consciousness
  • you believe someone is having their first seizure

Atypical absence seizure treatment

Treatment for atypical absence seizures typically includes the following medications:

  • ethosuximide
  • valproate
  • lamotrigine

Ethosuximide is usually the first-line treatment. Lamotrigine is generally less effective than the other two medications. Valproate tends to cause the most side effects.

These medications are also used to manage other types of seizures.

Some experts suggest that following a ketogenic diet may help manage symptoms, but more research is needed.

Brain surgery is sometimes performed in people with Lennox-Gastaut syndrome if other treatments fail.

How are atypical absence seizures diagnosed?

A doctor diagnoses atypical absence seizures by reviewing your symptoms, medical history, family history, and measuring your brain electrical activity with a device called an electroencephalogram (EEG).

People with atypical absence seizures tend to have a particular pattern of brain activity characterized by slow spikes of activity between seizures at a frequency of 1.5 to 2.5 Hertz and wave activity that’s asymmetrical, low amplitude, or irregular.

If you’re visiting the doctor for your child, it’s a good idea to take written notes of your child’s symptoms, or take a video if possible.

Takeaway

Atypical absence seizures tend to last about 15 to 30 seconds. When somebody has this type of seizure, they may seem like they’re daydreaming and become unresponsive.

If you think you or your child may be having seizures, it’s important to see a doctor. Different types of seizures are treated differently, so a proper diagnosis is necessary.

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