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Childhood absence epilepsy

Accounts for 10-17% of all cases of childhood onset epilepsy.

Childhood absence epilepsy and juvenile absence epilepsy or common idiopathic generalized epilepsies.

Childhood absence epilepsy and juvenile absence epilepsy have absence, early morning generalized tonic clonic and myoclonic seizures.

Childhood absence epilepsy and juvenile absence epilepsy are both relatively benign and usually remit, but can the lead to progressive myoclonic epilepsy syndromes.

Annual incidence has been estimated at 1-8 per 100,000 in children aged 0-15 years.

Girls represent 60-76% of patients.

Onset ranges from ages 3-13 years with a peak at ages 6-7 years.

A positive family history of epilepsy is present in about one third of patients.

Multifactorial pattern that involves both genetic and environmental factors.

ECA1 form, has been linked to chromosome band 8q24.

ECA2 form, in which patients have absence and febrile seizures, is caused by mutation in the GABRG2 gene on band 5q31.1.

A third form, ECA3, is caused by a mutation of the chloride channel gene CLCN2 on band 3q26.

Variants in the CACNA1H gene have been identified in childhood absence epilepsy.

These seizures are the initial seizures that occur in developmentally normal children.

Seizures are brief, most commonly lasting 5-10 seconds.

Seizures may occur 10-100 times a day.

Seizures usually occur spontaneously but may be precipitated by emotional, intellectual, or metabolic factors.

Absence status occurs in 10% of cases.

Manifests as a loss of responsiveness with cessation of ongoing activity.

Six types of absence seizures can be identified: (1) simple absence with impaired consciousness (10%), (2) absence with mild clonic components usually involving the eyelids (50%), (3) absence with atonic components resulting in gradual lowering of the head or arms (20%), (4) absence with tonic components, (5) absence with automatisms that are either perseverative (ie, the patient persists in what he is doing) or de novo such as lip smacking or swallowing (60%), and (6) absence with autonomic activities.

EEg is usually normal, although mild abnormalities may be present.

Patients who become seizure free ranges from 33-79.3%.

The longer the follow-up, the smaller the percentage of patients whose seizures are controlled.

Many patients develop generalized tonic-clonic seizures later in the course of the epilepsy.

Absence seizures may persist in about 6% of cases.

Generalized tonic-clonic seizures develop in about 40%, but infrequent, easily controlled, and generally occur 5-10 years after the onset of absences.

Juvenile myoclonic epilepsy is reported to occur in 44% of patients who do not have remission of their seizures.

Problems with cognition, social adaptation, or behavior may occur in one third of patients.

Most common form of pediatric epilepsy.

Associated with frequent daily, brief staring spells.

Typically begins at age 4-8 years of age, in a otherwise healthy appearing child.

EEG classically shows generalized spike-wave bursts of 3 Hz with normal background activity.

Associated with variable remission rates.

Affects children’s cognitive performance,and is associated and long term psychosocial difficulties.

Treatment is usually monotherapy with ethosuximide, valproic acid or lamotrigine.

Ethosuximide and valproic acid are significantly more effective than lamotrigine in controlling seizures (Glauser T).

Attention dysfunction was more common with valproic acid then with ethosuximide (Glauser T).

The best available agents fail almost 50% of the time to manage seizures in newly diagnosed cases.

No studies have demonstrated conclusive efficacy of any drug in this process.

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