儿童脊髓性肌萎缩症的临床特征及电生理分析

Clinical Manifestations and Electrophysiology Analysis of Spinal Muscular Atrophy in Children

目的探讨儿童脊髓性肌萎缩症(SMA)的临床及电生理特点。方法收集32例SMA患儿的临床资料,其中28例患儿行肌电图、运动神经传导速度及感觉神经传导速度等神经电生理检查,24例患儿行腓肠肌活检。结果32例SMA中,SMAⅠ型15例,SMAⅡ型12例,SMAⅢ型5例,均表现为进行性肌无力、肌萎缩,肌张力低下。各型SMA患儿起病年龄及病情轻重有其相应的特点。SMAⅠ型患儿不能竖头,均有呼吸肌受累表现,其中10例有颅神经受累症状。SMAⅡ型患儿能独坐,仅1例出现矛盾呼吸及吞咽困难。SMAⅢ型患儿能独站,其中3例可行走,均无呼吸肌受累表现。肌电图呈神经源性损害,主要表现为自发电位,其出现率为87%,运动单位时限延长(幅度30%～150%)、波幅增高(幅度90%～450%),28%运动神经传导速度轻度减慢(降幅24%～40%),93%肌肉复合动作电位波幅降低(降幅56%～99%),远端潜伏期均正常。感觉神经传导速度及诱发波幅均在正常范围。肌肉活检为典型的神经源性肌萎缩。结论根据临床特点、肌电图及肌活检结果可确诊SMA,重视SMA患儿的呼吸管理,可延长患儿生存时间,提高生活质量。

Objective To explore the features of clinical manifestations and electrophysiology of spinal muscular atrophy （SMA） in children. Methods The clinical features and laboratory data were analyzed in 32 children with SMA, electromyography tests were carried out in 28 patients and the muscle biopsy were performed in 24 cases. Results The 32 cases were subdivided into 3 clinical groups, 15 cases were SMA Ⅰ , 12 cases were SMAⅡ ,5 cases were SMAⅢ. They were all characterized by progressive muscle weakness associated with hyptonia and atrophy. The clinical distinction between SMA Ⅰ to SMAⅢreflected different age of onset and disease severity. All cases of SMA Ⅰ had symptoms of respiratory disability, only Ⅰ case of SMAII had paradoxical breathing and none of SMA Ⅲ had similarly symptoms. Eleetromyographic studies showed a pattern of denervation with no sensory involvement. The rate of spontaneous potential was 87% ,with gentle strain,the duration of motor unit was extended（30% - 150% ） and the amplitude of it was increased （90% -450% ）, the motor nerve conduction velocity was reduced slightly in 28% patients. The muscle biopsy provided evidence of skeletal muscle denervation with groups of atrophy. Conclusions The clinical features, the changes of electromyography and the muscle biopsy are valuable for diagnosis of SMA. Respiratory management will prolong survival and improve the quality of life for these patients.