Absence Seizures: Causes, Triggers & Diagnostic Pathway

Absence seizures (formerly petit mal) are brief (5–15 sec) generalized non-convulsive seizures with impaired awareness and EEG 3-Hz spike-wave discharges. Onset typically 4–12 years.

Etiologic Factors

• Genetic: Strong heritability; mutations in CACNA1H, GABRG2, SCN1A, SLC2A1 (GLUT1 deficiency).
• Neurotransmitter imbalance: GABAergic inhibition / glutamatergic excitation dysregulation in thalamocortical circuits.
• Neurodevelopmental: Immature synaptic pruning, network hyperexcitability.
• Structural: Rarely, cortical malformations, tumors.
• Metabolic triggers: Hypoglycemia, electrolyte disturbances.
• Environmental precipitants: Sleep deprivation, hyperventilation, photic stimulation, stress.

Diagnosis & Management

• EEG with hyperventilation/photic activation confirms.
• First-line: Ethosuximide (absence-only) or valproate (if mixed seizure types; avoid in girls of childbearing potential).
• Lamotrigine, levetiracetam as alternatives.
• ~70% remit by adolescence; lifelong epilepsy risk persists in some.

Refer to pediatric neurologist/epileptologist for comprehensive evaluation.