Childhood Absence Epilepsy

Question 1

Seizure

Answer 1

an episode of cerebral dysfunction leading to clinical changes in motor, sensory or autonomic function

Question 2

Seizure Epidemiology

Answer 2

Incidence 0.7 – 4.6 per 100,000 children
Prevalence 5-50/100,000
Represent approximately 3-10% of childhood epilepsies
Females > males (60:40)

Question 3

Seizure Genetic factors

Answer 3

Monozygotic twins concordant for absence epilepsy in 75% and 84% for EEG abnormalities
Incidence of seizures or EEG abnormalities in 1st degree relatives ranges from 15-44%

Question 4

Seizure Pathophysiologic mechanism

Answer 4

Thalamocortical oscillatory system

Calcium channels and GABAergic inhibition

Question 5

Simple absence

Answer 5

90% last between 5-15s, 3% of patients may have seizures >30s
Average of 100 seizures per day

Question 6

Complex absence

Answer 6

More common than simple
Automatisms – persistence of an action, mumbling, non-purposeful movements
Autonomic features – pallor, ∆HR, ∆RR, mydriasis, micturition (5-17%)

Question 7

Impairment of consiousness
Prominent motor activity
Myoclonic jerks, automatisms, atonic

Answer 7

Complex absence seizures

Question 8

Impairment of consiousness
Minimal motor activity
Eyelid fluttering, blinking

Answer 8

Simple absence seizures

Question 9

Onset 4-8y (maximum 6-7y)
Frequent absence seizures, often precipitated by HV
GTC seizures in 30% with onset

Answer 9

Childhood Absence Epilepsy

Question 10

Onset 4-30y (mean 13y)
Less frequent absence seizures
Duration may be longer with some preserved awareness
80% with GTC seizures, 15-25% with infrequent myoclonus

Answer 10

Juvenile Absence Epilepsy

Question 11

Infrequent absence seizures
GTC and myoclonic seizures (surrounding sleep) are predominant features
No remission but may be responsive to treatment

Answer 11

Juvenile Myoclonic Epilepsy

Question 12

EEG

Normal background organization and frequencies
Ictal discharges
Abrupt onset and offset
Generalized 3 Hz spike and wave
Frontal maximum
Spikes may become fragmented and irregular during sleep

Answer 12

Typical absence

Question 13

EEG

Often abnormal background with slowing and disorganization
Ictal discharges at 2-2.5 Hz, more irregular

Answer 13

Atypical absence

Question 14

Treatment of Sz

Answer 14

Anticonvulsants
Ethosuximide (Zarontin®) – acts on T type Ca current
Valproic Acid (Depakote®)
Lamotrigine (Lamictal®)
Leviteracetam (Keppra®) – JME

Question 15

Brief arrest in behavior for few seconds

asc. w/ abnormal activity

Answer 15

Absence seizure