myoclonic epilepsies, Jenn (and others)

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Have to hurry here, but this is a summary on the info I have on MAE. When I looked for other info on severe myoclonic eilepsies, I decided the details vary too much between papers to be able to summarise properly. Severe Myoclonic Epilepsy of Dravet, is also known as The Malignant Myoclonic Epilepsy of Dravet, yet one journal excerpt says it was inaccurately named, as the outcome could be benign. This differs from other articles I have read, I would suggest tapping into Medscape or Medline, and see what you come up with. Juvenile Myoclonic Epilepsy, which has a favourable prognosis, doesn't start until late childhood, some say 8 or 10 yrs onwards, so I have never looked too deeply into this one.

The Progressive Myoclonic Epilepsies (PME's) are as a result of inborn errors of metabolism, or mitochondrial diseases, such as MERRF, MELAS, Batten's disease, etc. These are what the various biopsies and blood enzyme assays are for, as well as in depth urine studies. The resultant epilepsy is a secondary manifestation of an underlying genetic metabolic disorder.

There is very little written about MAE, so not too many articles to conflict each other!

Myoclonic Astatic Epilepsy of Early Childhood, also known as MAE or Doose Syndrome : Similar to Lennox Gastaut Syndrome, a mixed generalised seizure disorder, but without the 'classic' LGS eeg pattern, and without tonic seizures (except in rare cases at night between 4 and 6 am). Predominant seizure type is myoclonic astatic, where a myoclonic jerk precedes the drop attack. Also seen are myoclonic jerks of limbs, including irregular twitching of extremities and facial features, and astatic seizures, or drop attacks. Absences are also seen in more than half the cases, as are generalised tonic clonic seizures. (GTC was 's presenting seizure type, but we rarely see these now). The child is almost always neurologically normal before seizure onset, there is never an underlying cause, eg, metabolic, brain malformation etc, as there often is in LGS. Focal seizures are also absent.

The eeg pattern depends on the predominant seizure type, and during sleep, spike and wave is regularly activated. Photosensitivity is common, but does not always show until age 5 onwards. The background rhythm slows during periods of frequent seizure activity, but usually reverts to back to normal, with stable alpha rhythm

present. This is in contrast to LGS where the background activity is almost always slowed, even when no seizure activity is present. During bouts of status in MAE, usually minor motor status, continual absences with twitching of extremities are seen, often interspersed with more violent myoclonic jerks (this is what has been through with the chicken pox) The eeg during status shows 2-3 c/s spike and wave, and continuous activity resembling hypsarrhythmia.

Differential diagnosis between MAE and Infantile Spasms (when seizure onset is in a younger child, ie, 6 mths to 2 yrs), is usually made when the predominant seizure type is myoclonic (and therefore polyspike and wave on the eeg), and when the seizures do not come in the 'series' of spasms (often tonic) seen in infantile spasms. Hypsarrhythmia is almost always present on the eeg with IS, even when the child is not clinically seizing.

Prognosis of MAE is variable, the outcome ranges from spontaneous remission in about 52 % of cases, often from age 7 onwards, to a malignant course with the progressive dementia often seen in LGS. Males are affected twice as often as females. Treatment options include valproate and ethosuximide, with ACTH indicated for refractory minor motor seizures, and primidone for tonic clonic seizures. Bear in mind that most of the info I have typed here is from the paper written by Herman Doose himself, and is dated 1992, with a lot more meds available now. (Not that any treatment except the diet have helped !)

There is almost always a genetic link, a close relative with epilepsy, even if it is a benign type syndrome that the relative may have. I have a first cousin with epilepsy, that started when she was 2 yrs old, this is apparently a close enough link to fit into this diagnosis.

Feel free to ask me more, will answer when I can. Have to go and do the swap at the hospital with 's Dad.

Hill, mother to 5, 7, and 21 mths in NZ