An absence seizure is a generalized onset seizure, which affects both sides of the brain at the same moment. During an absence seizure, you lose awareness of your surroundings.These seizures can cause a person to stare blankly, as though they are daydreaming. They may last around 15 seconds and can occur several times per day.
This article explains the causes, symptoms, and treatment options related to absence seizures. It also covers epilepsies characterized by absence seizures and their management.
What is an absence seizure?
Doctors may categorize an absence seizure as typical or atypical, according to the Epilepsy Foundation. They are brief and do not involve large movements or changes in muscle tone, unlike motor seizures, such as generalized tonic-clonic seizures.
Typical absence seizures
Typical absence seizures are more common than atypical absence seizures and usually last less than 10 seconds. Symptoms can include:
- stopping all activity, with the person possibly stopping talking mid-sentence
- staring into the distance
- having a blank look on the face
- eyes looking upward
- eyelids fluttering
- not responding to anything, or impaired awareness
Atypical absence seizures
Atypical absence seizures last 20 seconds or longer, and they start and end slower than typical absence seizures. The symptoms include those of a typical absence seizure but include more movements, such as:
- smacking the lips
- chewing movements
- hand motions and fidgeting
- limp muscles
- moving around
- responding to the environment
After a seizure of this type, you are likely to continue the activity you were doing before the seizure and may not be aware that you had a seizure. However, if you have many seizures throughout the day, you may be confused. You may not follow what has been going on around you.
What causes absence seizures?
Seizures are due to alterations in electrical activity in the brain. Doctors can measure these changes with an electroencephalogram (EEG). An absence seizure is marked by a generalized and rhythmic 3-Hertz spike-and-wave EEG pattern.
Often, doctors cannot find the specific reason for the absence seizure.
However, absence seizures may have a genetic link. Absence seizures are hallmarks of at least the following genetic epilepsies:
- childhood absence epilepsy
- juvenile absence epilepsy
- juvenile myoclonic epilepsy
- Lennox-Gastaut syndrome
The genetic disorder glucose transporter type 1 deficiency syndrome can also cause absence seizures. This is because the brain is not getting enough glucose, which it needs for energy.
Various things can trigger seizures, in general, and these can vary among people. Some triggers include:
- not taking your seizure medications consistently
- not getting enough sleep
- drinking alcohol
- withdrawing from some medications or alcohol
- taking medications that may interfere with your seizure drugs
How do doctors diagnose absence seizures?
An EEG helps diagnose the type of seizure. If the doctor needs to bring about a seizure to record by EEG, they may ask a child to hyperventilate for 3–4 minutes while they count out loud, with their eyes shut. This can bring on an absence seizure in over 9 in 10 children with childhood absence epilepsy.
The doctor will also ask you about your or your child’s absence seizures. They will need clear details of what happens during the seizures. The more specific you can be, the easier it will be for your doctor to make the correct diagnosis.
Genetic tests may also be a part of the diagnosis when the doctor suspects a genetic epilepsy syndrome.
Getting an accurate diagnosis is important because absence seizures can be misinterpreted as focal impaired awareness seizures. This type of seizure begins in one side of the brain and, like an absence seizure, may or may not involve movements. In addition, a doctor may misdiagnose an absence seizure as a staring spell, which does not involve changes in brain activity.
The doctor may diagnose epilepsy if the absence seizure is followed by a second one more than 24 hours later or if there is a 60%-or-higher chance of a second one.
How do you treat absence seizures?
If someone is having an absence seizure, stay with them and try to steer them away from anything that may cause them harm. Note the details about the seizure, including how long it lasts, as this information can be useful for diagnosis and the ongoing management of absence seizures.
You or your child may not need treatment, especially if the seizures are rare. However, if the seizures are frequent, a doctor may prescribe a medication. The medication works by stabilizing the electrical activity in your brain. Commonly prescribed medications include:
- ethosuximide (Zarontin)
- lamotrigine (Lamictal)
- valproic acid (Depakene)
- divalproex sodium (Depakote)
How long you or your child may need this medication will vary. You may need to try different combinations of medications or various dosages to manage the seizures. Some childhood absence epilepsies resolve in adolescence. However, lifelong treatment may be necessary.
Self-care and diet for absence seizures
Avoiding known triggers is another way to treat absence seizures. Make sure that you or your child is getting enough sleep and eating meals regularly.
Talk with a doctor about dietary therapy for epilepsy. There is some evidence to suggest that a ketogenic diet can help manage seizures. The keto diet is high in fats and low in carbohydrates, which provides more energy for the brain. A medium-chain triglyceride (MCT) diet is more flexible than a keto diet and may also help. An MCT diet includes more carbohydrates and proteins and incorporates MCT oil, which is a type of fat.
What are some coping tips for absence seizures?
You can live a full and active life with some absence epilepsies, especially with the support of medications and self-care. However, you or your child may need support in various areas of your life. Specific recommendations depend on the age of the person who is experiencing seizures. Here are some general tips:
- Communication and socializing: Talk with your child about their seizures and ensure that they get an opportunity to ask questions. Encourage them to safely take part in activities, build routines, and enjoy spending time with their family members and friends.
- Education and employment: Educate your child’s teacher and school nurse about your child’s seizures. If you are affected and you work, talk with your employer to ensure that you are safe while working. Keep in mind that the Americans with Disabilities Act covers epilepsy, according to a 2013 document from the U.S. Equal Employment Opportunity Commission.
- Bullying and discrimination: There can be a stigma attached to having seizures. Ask your child’s teacher to talk with the class about seizures and what to do if someone has one. If you have seizures, talk with your colleagues and friends.
- Self-care: Getting enough sleep, eating regular healthy meals, and following a keto diet may help reduce your risk of experiencing a seizure. You may also need support with managing stress or anxiety.
- Driving: Check with your local state regarding the laws for driving if you have seizures. You may wish to use public transport instead.
- Online information and support groups: Connecting and talking with others who have seizures can be both helpful and reassuring. Some support groups include:
- Epilepsy Foundation
- American Epilepsy Society
- International League Against Epilepsy
What is the outlook for someone with absence seizures?
The outlook for people with absence seizures and epilepsy depends on the specific type of epilepsy and seizures the person experiences. Around 7 out of 10 people with childhood absence epilepsy will have their absence seizures under control with epilepsy medications, according to Epilepsy Action.
Absence seizures usually stop by adolescence for 57–74% of children with
childhood absence epilepsy. It is rare for absence seizures to continue into adulthood.
Other frequently asked questions
Here are some other questions that people have asked about absence seizures.
Are absence seizures dangerous?
Even though they are brief, absence seizures can be dangerous when they occur during a particular activity, such as bathing, swimming, climbing, or driving. In addition, children who experience absence seizures often have impaired attention and memory.
Who gets absence seizures?
Absence seizures occur in children more frequently than in adults. Children are usually ages 4–14 years when they start having seizures. Females tend to experience absence seizures more than males.
How often do absence seizures occur?
Absence seizures can happen regularly and frequently — from 10 to more than 30 times per day.
Can you prevent absence seizures?
You may be able to reduce the frequency of your absence seizures by avoiding your triggers, taking your prescribed medications, and sleeping and eating well.
Absence seizures occur when someone loses awareness of their surroundings for around 15 seconds. The seizures are defined by a rhythmic spike-and-wave pattern on an EEG. These seizures can occur many times per day.
Absence seizures are associated with certain types of epilepsy that tend to affect children.
Taking medications and avoiding known triggers can help reduce the frequency of absence seizures.
Source: healthgrades.com, Rebekah Louise