Myoclonic‐Astatir Epilepsy: A Report of Three Intractable Cases.

Abstract

Purpose: Myoclonic‐astatic epilepsy (MAE), as first described by Doose (1970), is a rare generalized epilepsy of early childhood characterized by myoclonic, astatic, and myoclonic‐astatic seizures. Although valproate (VPA) seems to have proven efficacy for the treatment of MAE, a few patients are known to be resistant to antiepileptic drug (AED) therapy. We describe 3 patients with MAE who were non‐responsive to AEDs. Subjects: Case 1 was a 2‐year‐7‐month‐old boy first seen with generalized tonic‐clonic seizures (GTCS). He was born at full term with an uneventful delivery and his psychomotor development was normal. Computed tomography (CT) and magnetic resonance imaging (MRI) scans of the skull revealed no abnormalities. EEG showed monofrequent theta rhythms with parietal accentuation during wakefulness. He was given VPA with the recurrence of GTCS after a 2‐week seizure‐ free period. Both carbamazepine (CBZ) and zonisamide (ZNS), with the combination of VPA, showed no effectiveness. At the age of 2 years and 9 months he started to experience brief astatic seizures often followed by a short period of diminished responsiveness. Combined administration of VPA and ethosuximide (ESM) was temporarily effective, but he again developed astatic seizures. After adding clonazc‐ pam (CZP) to VPA and ESM at the age of 2 years and I I months, the frequency of the astatic seizures decreased, but they were not entirely abolished. Acetazolamide was given at the age of 3 years and 3 months, with only partial effectiveness. He was lost to follow‐up at the age 3 years and 7 months. Case 2, a 2‐year‐5‐month‐old boy, developed drop attacks which occurred in clusters of 0–50 times a day. He was first seen at the age of 2 years 1 I months, and his psychomotor development was normal. He was born weighing 2,144 g at 36 weeks of gestation after an uneventful pregnancy and delivery. EEG and MRI of the skull revealed no abnormalities. Shortly after his first visit, he experienced GTCS and VPA was started. After a 4‐month seizure‐free period, he began having sudden episodes of momentary head nodding. These episodes were not ameliorated with the addition of CBZ. The combi‐ nation of CZP and VPA achieved seizure control, but astatic seizures recurred at the age 3 years and 7 months. The seizures were satisfac‐ torily controlled after adding ESM to VPA, except for 2 episodes of astatic seizures. Case 3, a 1 year and 4 month old boy, was first seen with febrile seizures which recurred 4 times a day. PB was administered. He was born weighing 2,380 g at 37 weeks of gestation after an uneventful pregnancy and delivery. His psychomotor development was normal. Three siblings of his father had had seizure episodes as chil‐ dren. A CT scan revealed an arachnoid cyst of the right temporal fossa. EEG was normal. At the age of 1 year and 7 mouths he started to experience astatic seizures that were easily evoked by visual or photo stimulation. PB was changed to VPA at the age of 2 years and 2 months. At the age of 2 years and 4 months he experienced astatic seizures. The addition of ESM and later CZP to VPA showed temporary effectiveness. Even though he has been treated with the combina‐ tion of VPA, ESM, and mexiletine since the age of 2 years and 6 months, several monthly episodes of astatic seizures have been noted. Conclusions: In our experience, ESM seemed to be the most effective for the treatment of refractory minor seizures in patients with MAE. It is necessary to keep serum concentrations at higher levels, ranging from 109–124 mglL, to achieve favorable control. In 1 patient, mexiletine showed partial effectiveness.