Absence seizures are one of several kinds of generalized seizures. These seizures are sometimes referred to as petit mal seizures (from the French for "little illness", a term dating from the late 18th century). Absence seizures are characterized by a brief loss and return of consciousness, generally not followed by a period of lethargy (i.e. without a notable postictal state). Absence seizure is very common in children. It affects both sides of the brain. Epidemiology
Absence seizures affect between 0.7 and 4.6 per 100,000 in the general population and 6% to 8% in children younger than 15 years. Childhood absence seizures account for 10% to 17% of all absence seizures. Onset is between 4 and 10 years and peaks at 5 to 7 years. It is more common in girls than in boys. Etiology
An absence seizure is specifically caused by multifactorial inheritance. The voltage-gated T-type calcium channel is regulated by GABRG2, GABRG3, and CACNA1A2 genes. Inheritance of these genes is involved in etiology of absence seizure. The factors that trigger an absence seizure are lack of sleep and compliance, drinking alcohol, and benzodiazepine withdrawal, and use of medication that reduces the threshold of seizure such as Isoniazid, antipsychotics. Signs and symptoms
The clinical manifestations of absence seizures vary significantly among patients. Impairment of consciousness is the essential symptom, and may be the only clinical symptom, but this can be combined with other manifestations.
After 16 weeks of therapy, the freedom-from-failure rates for ethosuximide and valproic acid were similar and were higher than the rate for lamotrigine. There were no significant differences between the three drugs with regard to discontinuation because of adverse events. Attentional dysfunction was more common with valproic acid than with ethosuximide. If monotherapy fails or unacceptable adverse reactions appear, replacement of one by another of the three antiepileptic drugs is the alternative. Adding small doses of lamotrigine to sodium valproate may be the best combination in resistant cases. Although ethosuximide is effective in treating only absence seizures, valproic acid is effective in treating multiple seizure types including tonic-clonic seizure and partial seizure, suggesting it is a better choice if a patient is exhibiting multiple types of seizures. Similarly, lamotrigine treats multiple seizure types including partial seizures and generalized seizures, therefore it is also an option for patients with multiple seizure types. Clonazepam (Klonopin, Rivotril) is effective in the short term but is not generally recommended for treatment of absence seizure because of the rapid development of tolerance and high frequency of side effects. If medication is not effective in treating absence seizures, surgical treatment such as deep brain stimulation can reduce seizure episodes. Prevention
Medication alone cannot prevent absence seizure. It need to be supplemented by life-style changes such as exercise, stress reduction, good sleep hygiene, and healthy diet. Research shows that patient with ketogenic diet have 50% reduction in seizure episodes and 34% of patients become seizure free.