Absence Seizures in Children

1. Absence Seizures
Dr.Padmesh. V

2. • Typical absence seizures have a bimodal
distribution for age of onset;
• First peak at 5-8 years (childhood)
• Second peak near 12 years of age (juvenile)

3. • Childhood Absence Epilepsy (CAE)
• CAE is a childhood epilepsy syndrome occurring in
10–17% of all childhood onset epilepsy.
• The most common pediatric epilepsy syndrome.
• Females > males

4. • Usually start at 5-8 yr of age.
• No aura.
• Usually last for only a few seconds.

5. • Accompanied by eye lid flutter or upward rolling of
eyes.
• Absence seizures can have simple automatisms like
lip-smacking or picking at clothing.
• Head can minimally fall forward.
• No postictal period.

6. • Hyperventilation for 3-5 min can precipitate the
seizures and the accompanying 3 Hz spike–and–
slow-wave discharges.

7. • EEG:
• The ictal EEG of a typical absence seizure
demonstrates:
• generalized spike and wave complexes
• that are > 2.5 Hz, typically 3–4.5 Hz , and
• lasting ≥ 3 seconds.
3/sec spike-and-wave discharge of absence seizures with normal
background activity

8. • The presence of periorbital, lid, perioral or limb
myoclonic jerks with the typical absence seizures
usually predicts difficulty in controlling the seizures
with medications.

9. • Early onset absence seizures (before 4 yr)
Evaluate glucose transporter defect that is often
associated with low CSF glucose levels and an
abnormal sequencing test of the transporter gene.

10. • Atypical absence seizures :
• Associated myoclonic components.
• Tone changes of the head (head drop) and body.
• Variable impairments of consciousness.
• Last longer than typical absences.
• Precipitated by drowsiness.
• Not provoked by hyperventilation or photic stimulation.
• Usually more difficult to treat.
• 1-2 Hz spike–and–slow-wave discharges.

11. • Juvenile absence seizures:
• Similar to typical absences.
• But occur at a later age. (10-17 years)
• Accompanied by 4-6 Hz spike–and–slowwave and
polyspike–and–slow-wave discharges.
• Usually associated with juvenile myoclonic epilepsy

12. • TREATMENT:
• Initial treatment: Ethosuximide (less toxic than
valproate and more effective than lamotrigine.)
• Alternative drugs of first choice are lamotrigine and
valproate, especially if generalized tonic–clonic seizures
coexist with absence seizures. (as these 2 medications are
effective against the latter seizures whereas ethosuximide is not.)
• EEG often normalizes when complete seizure control is
achieved.

13. • TREATMENT:
• Other medications that could be used for
absence seizures include
– Acetazolamide,
– Zonisamide, or
– Clonazepam.

14. • Outcome and Prognosis of Childhood Absence
Epilepsy
• Remission rates : 21%–74%
• Although labeled “benign”, the clinical course of CAE is
variable and remission rates are far lower than in other
classic benign idiopathic epilepsies such as Benign Rolandic
Epilepsy.
• Multiple studies report that GTCs ultimately develop in
roughly 40% of children with absence seizures at onset.

15. • Outcome and Prognosis of Childhood Absence
Epilepsy
• GTCs often occur 5 to 10 years after the onset of
the absence seizures between 8–15 years old.
• Risk factors include:
– Onset of absence seizures after 8 years old,
– Male sex,
– Lack of response to initial therapy and
– Therapy with only an anti-absence drug.
• Accidental injury is common.

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