Prevalence
~2% to 3% of all epilepsies and around 8% to 10% of idiopathic generalized epilepsies (IGE) in adults >20 years.

Age at onset
Peak at 9 to 13 years (70% of the patients) but range is from 5 to 20 years. Myoclonic jerks (in 20% of patients) and generalized tonic-clonic seizures (GTCS; nearly in all) usually begin 1 to 10 years after the onset of absences.

Sex
Males = females.

Neurological and mental state
Normal.

Etiology
Genetically determined but mode of transmission and relation to other forms of IGE have not yet been established. JAE may be linked to chromosomes 8, 21, 18, and probably 5.

Clinical manifestations
JAE manifests with severe typical absence seizures; many patients (80%) also suffer from GTCS and 1/5 have sporadic myoclonic jerks.

Absence seizures are severe and frequent, often daily, and very similar but milder than those of childhood absence epilepsy. Duration varies from 4 to 30 sec (~16 sec).

GTCS are probably unavoidable in untreated patients. GTCS are usually infrequent but they may also become severe and intractable.

Myoclonic jerks are infrequent, mild, and of random distribution. They occur in the afternoon hours when the patient is tired rather than in the morning after awakening.

Seizure-precipitating factors
Typical absence seizures are nearly invariably provoked by hyperventilation. Mental and psychological arousal is other main precipitating factor for absences. Conversely, sleep deprivation, fatigue, alcohol, excitement, and lights alone or usually in combination are the main precipitating factors for GTCS. Clinical photosensitivity is exceptional or may not exist.

Inter-ictal EEG
Normal background or with mild abnormalities only. Focal epileptiform abnormalities and abortive asymmetrical bursts of spike/multiple spikes are common.

Ictal EEG
Generalized 3 Hz (2.5 to 4 Hz) spike or polyspike slow-wave complexes.

Prognosis
JAE is a lifelong disorder, although seizures can be controlled in 70% to 80% of patients. Absences and GTCS may become intractable in 1/5 of patients, particularly if appropriate treatment is not initiated early.

Differential diagnosis
Mainly from other IGEs such as childhood absence epilepsy or juvenile myoclonic epilepsy.

Management options*
Valproate is the drug of choice but lamotrigine and levetiracetam are possible alternatives.

Patients should be warned with regard to precipitating factors of GTCS.

*Expert opinion, please check FDA-approved indications and prescribing information

This page was adapted from:

The educational kit on epilepsies: The epileptic syndromes By C. P. Panayiotopoulos Originally published by MEDICINAE 21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007

Authored By: 
C. P. Panayiotopoulos MD, PhD, FRCP
I<
Authored Date: 
01/2006
Reviewed By: 
Steven C. Schachter MD
on: 
Sunday, June 1, 2008