Reviewed by DR. D. DATTA.
Ex. Emergency Medical Officer.
Absence seizures, previously called petit mal epilepsy, is a type of seizure that involves a sudden, brief lapse of awareness (usually not lasting more than 20 seconds). Symptoms start at childhood or adolescence.
During the attack the child cannot understand what is going on around him. As a result, the patient stops whatever he or she is doing for a few seconds. It occurs suddenly without prior warning and the patient regains quick consciousness and usually resumes what he or she was doing before the attack.
The patient cannot remember the incident after he regains awareness.
Due to quick return of normal awareness the patient does not fall, and physical injury does not occur.
Absence seizures occur in 5 to 8 in every 100,000 people and 10% of all childhood seizures belong to this category.
Symptoms of absence seizures
During the attack there is a sudden stop in motion or activity.
The patient may look like he or she is staring blankly, eyes may turn upwards.
There is a sudden return to normal activity when seizure ends.
There may be smacking of lips,
Fluttering of eyelids,
Chewing motion in mouth,
Small movements of both hands.
Absence seizures may occur daily or even more than a hundred times a day. Due to its short duration, it may remain unnoticed and undiagnosed for many months or several years.
Parents or teachers may think that the child is not paying attention or daydreaming.
Muscle jerking and shaking movements indicate that other types of seizure coexist with absence seizure.
Causes of absence seizures
Exact cause of absence seizures is not known. It may be genetic or due to gene mutation.
Electrical impulses originate from nerve cells (neurons) of the brain. When there is discharge of abnormal electrical impulses from brain cells seizure occurs.
Risk factors –
Age- children between 4 to 14 years are more prone to absence seizures.
Sex- absence seizures is more common in female.
Family history – in 50% cases there is a positive family history of absence seizures in a close relative.
Complications of absence seizures
Most children outgrow absence seizures at the age of 18 to 19 years.
When absence seizures occur several times a day it may affect learning and behavioral problems. There may be social isolation.
Sometimes patients may develop other types of seizures such as generalized tonic clonic seizure.
Patients may need prolonged or lifelong treatment with anti-seizure medicines.
There is risk of side effects of medicines used to control seizure.
Diagnosis of absence seizures
Sometimes absence seizures remain undiagnosed for years due to its brief period and as the patient returns to normal activity as soon as seizures stop. There is no post seizure confusion. Somebody who is present during the incident may think that the child is not giving attention or daydreaming.
Daydreaming and absence seizures can be differentiated by close observation. Daydreaming usually occurs during periods of boredom but absence seizures can occur at any time even during physical activity. Daydreaming tends to continue for a prolonged period. Somebody can interrupt to stop it. Absence seizures end quickly, usually within 10 to 20 seconds, but cannot be interrupted.
Proper history from a person such as a family member or teacher may help to diagnose it.
History of absence seizure in close relatives may be present.
Investigations-Â
EEG- Most commonly used investigation to diagnose absence seizure. This is a painless procedure. Electrodes are attached to the scalp by paste. The EEG machine records brain electrical activity and there is abnormality in EEG (generalized bilaterally synchronous spike and wave complexes at a frequency of 3/s).
Rapid breathing (hyperventilation) during an EEG recording may initiate absence seizure.
CT or MRI- CT or MRI may be used to exclude any other problem in the brain such as brain tumour.
Treatment of absence seizures
1 Antiepileptic (antiseizure) drugs:
There are several medicines to treat absence seizures.
Ethosuximide (zarontin) – This is the most commonly used drug to treat absence seizures. There may be side effects such as nausea, vomiting, sleepiness or insomnia.
Valproic acid- valproic acid is used in children. It is also used in children when there is coexistence of grand mal seizures along with absence seizures. It is not recommended in women during pregnancy or while trying to conceive, because it may cause birth defects of the fetus.
Hepatic and renal dysfunction, “Reye like” syndrome, bleeding, alopecia, excessive weight gain, aggravation of polycystic ovarian disease and false positive urine sugar tests are other possible side effects of valproic acid.
Lamotrigine is used sometimes.
Take medicines in the proper dose and at the proper time. Don’t stop taking medicines without advice from your doctor.
2 Lifestyle changes-
Lack of adequate sleep, stressful life, physical and mental exhaustion can trigger seizures.
Get enough sleep,
Avoid stress if any,
Avoid physical and mental exhaustion
Diet- sometimes a ketogenic (low carbohydrate and high fat) diet can improve seizure control. It may be tried when medicines fail to control seizure.
3 Education- Family members of the patient must be educated about the nature of the disease. They must support the child and know when they should consult a doctor. At school the child should not face any stigma or isolation. Teachers should be informed about the disease of the child and which activities should not be performed by the child at school and what to do when seizures occur at school.
4 There may be some restrictions like driving, cycling, swimming, operating dangerous machinery or working near a fire. There must be a prolonged seizure free period and the doctor must be consulted before driving or swimming. Don’t swim unless somebody is nearby.
There are many people living with seizure disorders. So don’t feel alone. Communicate with local support groups or online support communities for help if you need.
