What Is Absence Epilepsy?
Epilepsy is a nervous system disorder that causes seizures, which are temporary changes in brain activity. Doctors categorize different types of epilepsy based on the kind of seizure they cause. Absence epilepsy is characterized by petit mal seizures, also known as absence seizures. These seizures are brief, usually less than 15 seconds, and have symptoms that may be barely noticeable. However, loss of consciousness, even for such a short time, can make absence epilepsy dangerous.
Recognizing a Petit Mal Seizure
Petit mal seizures most commonly affect children ages 5 to 9, although they can occur in adults as well. Children with epilepsy may experience both petit mal and grand mal seizures, which are larger-scale seizures.
Signs a person may be experiencing a petit mal seizure include:
- staring off into space
- smacking the lips together
- fluttering eyelids
- stopping speech mid-sentence
- making sudden hand movements
- leaning forward or backward
- appearing suddenly motionless
Children with absence epilepsy are often believed to be misbehaving or inattentive.
A child’s teacher is often the first to notice absence epilepsy symptoms. The child appears temporarily “absent” from his or her body—hence the term absence epilepsy.
You can tell if a person is experiencing an absence seizure, as opposed to some other type of episode that resembles an absence seizure, because an absence seizure cannot be interrupted with touch or sound. Large-scale seizures may begin with an aura or warning sensation. However, petit mal seizures typically occur suddenly and with no warning. This makes taking precautions to protect the patient important.
What Causes Absence Epilepsy?
Your brain is a complicated organ that the body relies on to maintain your heartbeat and breathing. The nerve cells in your brain communicate with each other by sending electrical and chemical signals. A petit mal seizure interferes with this electrical activity in the brain. During a petit mal seizure, your brain’s electrical signals repeat themselves. This pattern typically lasts about three seconds each cycle. A person who has absence seizures may also have altered levels of neurotransmitters, the chemical messengers that help cells communicate.
Researchers have not identified a specific cause for absence epilepsy. The condition may have a genetic component in some patients. Hyperventilation or flashing lights may trigger a petit mal seizure in others. For some patients, physicians may never detect a distinct cause.
Potential Complications from Petit Mal Seizures and Absence Epilepsy
Petit mal seizures typically last less than 15 seconds before the person returns to normal behavior. The patient does not typically have any memory of the past few moments or the seizure itself. Some petit mal seizures last longer. These are known as atypical petit mal seizures and can last several minutes.
While petit mal seizures may have to do with the brain, they do not cause brain damage. Most children with absence seizures will not have affected intelligence though some may have learning difficulties because of the lapses in consciousness.
As long as a person has not been injured during the seizure, a full recovery can be made almost immediately. Falls do not typically happen during the seizure. A person can experience petit mal seizures a dozen or more times per day without any ill effects.
Because the patient is unaware the seizure is taking place, others are usually the first to notice the petit mal seizures.
Children with absence epilepsy often outgrow the condition. However, some patients may have absence epilepsy that progress to longer seizure episodes or larger seizure types.
How Is Absence Epilepsy Diagnosed?
A neurologist specializes in diagnosing nervous system disorders such as absence epilepsy. Neurologists will evaluate:
- overall health
- medications taken
- pre-existing conditions
- imaging and brain wave scans
A physician typically will try to rule out other causes of your symptoms before diagnosing absence epilepsy. For example, a physician may order a brain scan using a magnetic resonance imaging (MRI) machine. This scan captures detailed views of brain vessels and areas where potential tumors could rest.
Another diagnostic method involves using bright, flickering lights or hyperventilation to trigger a seizure. During this test, an electroencephalography (EEG) machine measures brain waves to determine any function changes.
How Is Absence Epilepsy Treated?
Anti-seizure medications are available to treat absence epilepsy. However, determining the right medication involves trial and error and can take time. A physician may start with low dosages of anti-seizure medications and adjust based on results.
Some examples of medications used to treat absence seizure are:
- ethosuximide (Zarontin)
- lamotrigine (Lamictal)
- valproic acid (Depakene, Stavzor)
Women who are pregnant or are thinking of becoming pregnant should not take valproic acid due to its increased risk for birth defects.
Because absence epilepsy results in temporary loss of awareness, certain activities can be dangerous. These include driving and swimming during which a lapse of consciousness might cause an accident or drowning. A physician may restrict a patient’s activity until the petit mal seizures have been controlled for some time. States also may have laws about how long a person must go without a seizure before getting back on the road.
Those with absence epilepsy may wish to wear a medical identification bracelet. This helps emergency responders know how to handle the patient in case of emergency. Patients also may want to educate loved ones on what to do if a seizure occurs.
What Is the Long-Term Outlook for Absence Epilepsy?
With regular treatment, an estimated 80 percent of absence epilepsy patients go into remission, according to New York University’s Langone Medical Center (NYU). Many children outgrow absence epilepsy in their teens. Absence seizures can usually be controlled with anti-seizure medication, and this will help to avoid any social or academic difficulties.