CHILDHOOD ABSENCE EPILEPSY

Overview
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Seizure Classification
Generalized onset seizure
- Motor Onset
- Non-Motor Onset
Focal Onset Seizure
- By Onset Feature
- Focal to Bilateral Tonic-Clonic
- Hemispheric lateralization
- Lobar localization
  - Frontal
  - Temporal
  - Parietal
  - Occipital
Unknown Onset Seizure
Epilepsy Classification
Generalized Epilepsy
Focal Epilepsy
Generalized and Focal Epilepsy
Unknown Epilepsy
Epilepsy Syndromes
Neonatal/Infantile
- Self-limited neonatal seizures and Self-limited familial neonatal epilepsy
- Self limited familial and non-familial infantile epilepsy
- Early myoclonic encephalopathy
- Ohtahara syndrome
- West syndrome
- Dravet syndrome
- Myoclonic epilepsy in infancy
- Epilepsy of infancy with migrating focal seizures
- Myoclonic encephalopathy in non-progressive disorders
- Febrile seizures plus, genetic epilepsy with febrile seizures plus
Childhood
- Epilepsy with myoclonic-atonic seizures
- Epilepsy with eyelid myoclonias
- Lennox-Gastaut syndrome
- Childhood absence epilepsy
- Epilepsy with myoclonic absences
- Panayiotopoulos syndrome
- Childhood occipital epilepsy (Gastaut type)
- Photosensitive occipital lobe epilepsy
- Childhood epilepsy with centrotemporal spikes
- Atypical childhood epilepsy with centrotemporal spikes
- Epileptic encephalopathy with continuous spike-and-wave during sleep
- Landau-Kleffner syndrome
- Autosomal dominant nocturnal frontal lobe epilepsy
Adolescent/Adult
- Juvenile absence epilepsy
- Juvenile myoclonic epilepsy
- Epilepsy with generalized tonic-clonic seizures alone
- Autosomal dominant epilepsy with auditory features
- Other familial temporal lobe epilepsies
Any Age
- Familial focal epilepsy with variable foci
- Reflex epilepsies
- Progressive myoclonus epilepsies
Epilepsy Etiologies
Genetic Etiology
- Chromosomal abnormalities
- Gene abnormalities
Structural Etiology
- Malformations of cortical development
- Vascular malformations
- Hippocampal sclerosis
- Hypoxic-Ischemic
- Traumatic brain injury
- Tumors
- Porencephalic Cyst
Metabolic Etiology
Immune Etiology
- Rasmussen syndrome
- Antibody mediated
Infectious Etiology
Unknown Etiology
- Febrile infection related epilepsy syndrome
Epilepsy imitators

CHILDHOOD ABSENCE EPILEPSY

Background

The background is normal. Occipital intermittent rhythmic delta activity (OIRDA) may be seen in a third of children with childhood absence epilepsy, at a frequency of 2.5-4 Hz, and may have a notched appearance.

CAUTION Focal slowing seen consistently in one area right arrow consider structural brain abnormality.

CAUTION Generalized slowing is not seen.

Interictal

Generalized spike-and-wave, or fragments of generalized spike-and-wave are seen in the interictal EEG. These are brief (usually < 2 second) and most commonly seen in sleep.

CAUTION Although focal spikes (as fragments of generalized spike-and-wave) can occur, if they consistently arise in one area right arrow consider structural brain abnormality.

Activation

EEG abnormality and absence seizures are provoked by hyperventilation. If hyperventilation is poorly performed, generalized spike-and-wave may not be triggered.

Intermittent photic stimulation triggers generalized spike-and-wave in a small proportion of individuals.

EEG abnormality is enhanced by sleep deprivation and by sleep. Generalized spike-and-wave often becomes fragmented with sleep deprivation or in sleep. Fragmented generalized spike-and-wave can appear focal or multi-focal but usually is not consistently seen in one area. The morphology of the focal spike-and-wave typically appears similar to the generalized spike-and-wave.

CAUTION Where hyperventilation is performed well for three minutes and no generalized spike-and-wave is seen, childhood absence epilepsy is unlikely.

Ictal

Regular 3 Hz generalized spike-and-wave occurs associated with absence seizures. Polyspike-and-wave can occur in the ictal EEG.

CAUTION Slow spike-and-wave (<2.5Hz) is exclusionary.

eeg
Example of 3Hz generalized spike-and-wave seen on the ictal EEG