Juvenile myoclonic epilepsy
- Aka: bilateral myoclonus.
- 5–10% of cases of epilepsy.
- An idiopathic generalized epilepsy syndrome with age-related onset consisting of 3 seizure types (may have one or all types):
- Absence (5-14 years),
- Myoclonic jerks (9-18 years)
- Predominantly after waking
- Generalized tonic-clonic seizures (9-26 years)
- Predominantly after waking
- EEG
- Paroxysmal spike, polyspike, and wave complexes that may be regular at 3-5 Hz but often are irregular with 2- to 10-Hz components.
- Photoconvulsive effect on the EEG has been described in at least one third of cases.
- Hyperventilation less reliably than in childhood absence epilepsy or juvenile absence epilepsy.
- Strong family history (link to the HLA region on the short arm of chromosome 6).
- Treatment: depakene
Juvenile absence epilepsy
- A type of idiopathic generalized epilepsy.
- Onset is from age 8 to age 16 years,
- Peak occurrence at 10-12 years of age.
- Vs childhood absence epilepsy
Feature | Childhood absence epilepsy | Juvenile absence epilepsy |
Age of onset | 4-10 yrs | 8-16 yrs |
Fq of absence seizures | Higher | Lower |
Fq of generalized tonic clonic seizure | Lower | Higher |
Probably of seziure going into adulthood | Lower | Higher |
impairment of consciousness | Severe | Moderate |
Fq in a day | Multiple times a day | Once or in a cluster within an hour after waking |
FHx of epilepsy | 15%; | 11% |
EEG | 3Hz spike and slow wave discharges on ictal EEG | Spike and wave slightly faster |
- Absence seizures are predominant.
- The level of retained consciousness may vary significantly from seizure to seizure in the same patient.
- The classic clinical feature
- “Simple absence” with staring and altered alertness
- Sometimes “complex absence” with blinking or head nodding).
- Seizures are typically triggered by
- Hyperventilation OR
- Sleep deprivation.
- EEG: Interictal background activity is usual normal, spike and wave slightly faster (3.5-4 Hz).
- Treatment
- Ethosuximide
Others
- Epilepsy with generalized tonic-clonic seizures alone
- Progressive myoclonus epilepsies
- Autosomal dominant epilepsy with auditory features
- Familial temporal lobe epilepsies
- Familial focal epilepsy with variable foci and reflex epilepsies
- Have a less specific relationship with age of onset.
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