Dramatic Effect of Ethosuximide on Epileptic Negative Myoclonus: Implications for the Neurophysiological Mechanism
Dramatic Effect of Ethosuximide on Epileptic Negative Myoclonus: Implications for the Neurophysiological Mechanism
复制标题
乙舒酰亚胺对癫痫阴性肌阵挛的显着作用：对神经生理机制的影响
作者：
H. Oguni;Takashi Uehara;Teruyuki Tanaka;M. Sunahara;Michiko Hara;M. Osawa
癫痫阴性肌阵挛(ENM)是最近定义的一种癫痫发作类型，见于各种癫痫综合征。虽然长期预后良好，但由于ENM的明显耐药性质，儿童时期的定位相关癫痫(LRE)合并ENM的治疗有时很困难。我们评价了10例ENM患者应用抗癫痫药物(AEDs)的疗效。8名患者接受了卡马西平治疗，但没有一人好转。氯硝西潘和丙戊酸的反应不可预测，而乙琥胺(ESM)作为辅助治疗的6例患者ENM均得到完全控制。ENM对CBZ和ESM的药理反应与失神惊厥非常相似。根据SPECT和发作期EEG的结果以及本研究的药理学反应，我们倾向于假设ENM是通过对运动皮质的直接抑制作用而产生的，从而导致由尖-慢波复合波产生的自主肌肉收缩中断，这与失神发作的机制相一致。如果在诊断LRE时选择了错误的AED，如PHT或CBZ，则ENM难以治疗和持续。我们建议在LRE的临床病程中发生ENM时进行ESM试验，而不考虑病因。
Epileptic negative myoclonus (ENM) is a recently defined epileptic seizure type seen in various epileptic syndromes. Although the long-term prognosis appears to be favorable, the treatment of localization-related epilepsy (LRE) with ENM in childhood is sometimes difficult due to the apparently pharmaco-resistant nature of ENM. We evaluated the effects of antiepileptic drugs (AEDs) in 10 patients with ENM. Carbamazepine was administered to eight patients, none of whom improved. Responses to clonazepam and valproic acid were unpredictable, whereas ethosuximide (ESM) achieved complete control of ENM in all six cases treated with this drug as adjunctive therapy. The pharmacological responses of ENM to CBZ and ESM were quite similar to those of absence seizures. According to the SPECT and ictal EEG findings in addition to the pharmacological responses from this study, we favor to postulate that ENM is produced by a direct inhibitory action on the motor cortex resulting in the interruption of voluntary muscle contraction as generated by sharp-slow wave complexes, compatible with the mechanism considered to underlie absence seizures. ENM are refractory to treatment and persisting if the wrong AEDs, such as PHT or CBZ, are selected at the diagnosis of LRE. We recommended a trial of ESM when ENM develops during the clinical course of LRE regardless of etiology.