Childhood absence epilepsy

Childhood absence epilepsy (CAE), also known as pyknolepsy, is one of the most common epilepsy syndromes in children. It is a genetic generalized epilepsy characterized by frequent, brief episodes of impaired consciousness called absence seizures. These seizures typically last 4 to 20 seconds and can occur dozens to hundreds of times per day. During an episode, the child appears to stare blankly and becomes unresponsive, often with subtle motor features such as eyelid fluttering, lip smacking, or mild hand automatisms. There is no warning before the seizure and no confusion afterward; the child resumes normal activity immediately. The condition primarily affects the central nervous system, specifically involving abnormal electrical activity in the brain. CAE typically begins between the ages of 4 and 10 years, with a peak onset around 5 to 7 years. It is slightly more common in girls than boys. The hallmark electroencephalographic (EEG) finding is bilateral, synchronous, symmetric 3 Hz spike-and-wave discharges on a normal background. Hyperventilation reliably provokes these discharges and is used as a diagnostic tool during EEG recording. Neurological examination and brain imaging are typically normal. Intelligence and development are generally unaffected, though frequent unrecognized seizures can impair school performance and attention. The prognosis for CAE is generally favorable. First-line treatment includes antiseizure medications such as ethosuximide, which is preferred for absence seizures alone, and valproic acid, which may be chosen if generalized tonic-clonic seizures are also present or suspected. Lamotrigine is considered a second-line alternative. With appropriate treatment, seizure control is achieved in approximately 60–70% of patients. Seizures remit by adolescence in the majority of cases, though a proportion of patients (approximately 10–20%) may develop generalized tonic-clonic seizures or evolve into juvenile absence epilepsy or juvenile myoclonic epilepsy. The genetic basis is complex, with susceptibility genes including GABRG2, GABRA1, CACNA1H, and others implicated, though no single gene accounts for most cases.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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