Absence Seizures

Absence seizures or petit mal seizures are brief seizures that cause a sudden lapse in awareness. An absence seizure lasts between 10 seconds to 20 seconds. Barely noticeable, an absence of seizure looks like daydreaming or lack of attention to an onlooker. In most cases, the absence of seizures causes no long-term issues and can be easily treated with anti-seizure medications and a healthy diet.

Alternate Name

Petit mal seizures, Childhood absence epilepsy, pyknolepsyAssociated Anatomy

Abnormal electrical activity in the brain

Signs or Symptoms of Absence Seizures

Absence seizures generally last between 10 seconds to 20 seconds. Symptoms of absence seizures one should look out for are:

• Leaning backward or forward
• Fluttering eyelids
• Suddenly stopping speech in the middle of a sentence
• Blankly staring into space
• Chewing motions
• Suddenly appearing motionless
• Sudden small movements of both hands
• No memory of the episode

Causes of Absence Seizures

Currently, the exact cause behind absence seizures is yet to be understood completely. Studies indicate that a genetic predisposition or a family history may play a major role in the development of absence seizures. Research has identified some triggers that cause absence seizures. These include:

• Use of drugs
• Use of alcohol
• Little or lack of sleep
• Stress or overexcitement
• Not taking medications as per doctor’s instructions
• Bright or flashing lights
• Loud noise
• Sudden withdrawal from medications
• Taking medications that may increase the likelihood of absence seizures, such as antipsychotic medications

Typical Test For Absence Seizures

The first step in diagnosing absence seizures is to take a detailed description of the symptoms, conduct a physical exam, and understand the overall medical history of the patient. Once this is completed and all other possible conditions ruled out, the doctor may ask the patient to get the following tests done. These include:

• Electroencephalogram (EEG) - This is a medical test where small electrodes are attached to the patient’s scalp to measure and monitor the electrical activity in the brain. This test is used to check for any changes in brain functioning. It is also used to study the pattern during an absence seizure and normal brain activity.
• Brain scans - Imaging tests such as Magnetic Resonance Imaging (MRI) scans are conducted to get a detailed image of the brain and rule out potential medical conditions such as tumors.

Absence Seizures Treatment

As per the symptoms, doctors opt for antiseizure medications for absence seizures treatment. The doctor may start with the lowest dose of medication and see the effect it has on the seizures. Depending on the frequency and severity of the seizures, the doctor may either increase the dosage or switch to another medication for better results. Once the child is seizure-free for two years, the doctor may slowly stop the medication. Some of the medications prescribed for the absence seizures are:

• Zarontin - In most cases of absence seizures, the doctors prescribe this medication. Patients mostly respond well to this medication but may experience side effects such as nausea, vomiting, hyperactivity, or trouble sleeping.
• Depakene - This medication is given to children when they experience both absence seizures and grand mal seizures.
• Lamictal - Studies suggest that this medication is less effective than the above two but shows fewer side effects than Depakene or Zarontin.

Risk factors of Absence Seizures

A variety of risk factors can increase the chances of an absence seizure. They are:

• Family history - A family history of epilepsy increases the risk of developing absent seizures in children
• Age - Absence seizures are commonly observed between children of 4 to 12 years of age, typically peaking between ages 6 to 7 years
• Triggers - Factors such as flashing lights or hyperventilation may have a higher risk of triggering absence seizures in certain individuals

Possible Complications of Absence Seizures

In most cases, children outgrow the absence of seizures after a certain period. However, certain children may continue to experience absence seizures which may progress into intense and longer seizures. While there are no long-term negative effects or damages, children may experience difficulties in learning and may get injured.

Prevention of Absence Seizures

Primary Prevention

There is no way to prevent absence seizures completely as researchers believe that genetics play a major role in the development of absence seizures.

Secondary Prevention

Some of the following measures can help in the management of absence seizures when traditional medications fail to do so.

• Diet modification - Doctors recommend eating a diet high in protein and low in carbohydrates may be effective in controlling seizures
• Get adequate sleep - Little or lack of sleep can contribute to one getting absence seizures often. Get enough sleep every night to reduce the frequency of seizures.
• Activities under supervision - Since patients with absence seizures don’t realize they are having one, activities such as swimming or driving should be done in the presence of another person.

Differential Absence Seizures Diagnosis

Doctors may diagnose absence seizures as focal onset seizures or partial seizures. These seizures originate in one part of the brain and may also cause impaired awareness in the patient. Some of the essential symptoms of focal onset seizures from absence seizures are:

• They last between 30 to 45 seconds
• The patient may experience an aura before the onset of the seizure
• A state of confusion and sleepiness after the episode

Epidemiology

• The occurrence of absence seizures is between 0.7 to 4.6 per 100,000 in the general population
• The occurrence of absence seizures is between 6 to 8 per 100,000 in children younger than 15 years of age
• Absence seizures commonly develop in children between the ages of 4 years to 12 years
• Girls have more and more frequent episodes of absence seizures than boys

Prognosis

Expected Prognosis

Fortunately, advancement in medicine has made it possible to completely treat one of the absence seizures. Most children respond well to antiseizure medications. Studies show that 57% to 74% of these seizures completely go away by the time children reach their teenage years and no longer require medication.

Natural Progression

Absence seizures, if left untreated, may progress to more complex forms of epilepsy such as generalized tonic-clonic seizures and may develop learning difficulties and behavioral issues.

Pathophysiology

Although the exact mechanism behind absence seizures is not completely understood, studies indicate that abnormal firing of cells in the cortico-thalamic-cortical system may contribute to the development of absence seizures. With a genetic predisposition, some people are at an increased risk of developing these seizures.