甲基丙二酸血症患儿正中神经体感诱发电位变化的意义

Changes of Median Nerve Somatosensory Evoked Potentials in Children with Methylmalonic Academia

目的观察28例甲基丙二酸血症（MMA）患儿正中神经体感诱发电位（MN-SEP）特点,探讨MN-SEP在MMA患儿中的临床应用价值。方法对1999年1月-2007年5月临床确诊的28例MMA患儿进行MN-SEP检查。其中男21例,女7例;年龄5个月-12岁5个月。其尿液有机酸测定采用气相色谱/质谱联用分析（GC-MS）,MN-SEP检查应用尼高力肌电型诱发电位测试仪对MMA患儿进行检测。结果28例患儿尿液中甲基丙二酸水平明显升高。23例于婴儿期起病和2例于幼儿期发病的患儿临床表现以神经系统损害为主;1例学龄前期起病和2例学龄晚期起病的患儿智力、运动倒退突出。患儿均伴头颅影像学改变,头颅CT或MR I主要表现为脑沟增宽、脑室扩大脑室旁低密度灶。28例MMA患儿中24例MN-SEP异常（85.7%）,主要为2例（7.1%）N9潜伏期延长,14例（50%）N9-N13峰间期延长,19例（67.9%）N13-N20峰间期延长,1例（3.6%）N20波形消失。结论MMA患儿的MN-SEP异常发生率高,MN-SEP检测有助于发现MMA患儿的神经系统感觉传导功能异常。

Objective To investigate the characteristics and clinic value of median nerve somatosensory evoked potentials（MN-SEP） in children with methylmalonic academia（MMA） through analyzing the data of 28 MMA children′s MN-SEP.Methods From 1999 to 2007,28 MMA children who had 21 male and 7 female were diagnosed in the hospital by urine organic acids analysis using gas chromatography-mass spectrometry（GC-MS）.Their MN-SEP were recorded with Nicolet myoelectricity evoked potentials otentiometer.Results All of the 28 Children had remarkedly increased urine methylmalonic acid.Twenty-three of them had the onset before 1 year old and one at toddler age,with mental retardation.The others had psycho-motor degeneration at preschool age or late school age.All of them had abnormal findings in head CT or MRI：enlarged cortical sulci,ventriculomegaly,low density areas around the cerebral ventricals.Twenty-four had abnormal findings of MN-SEP.The abnormality detection rate of MN-SEP was 85.7%.The main abnormal parameters in MN-SEP were latency prolongation in wave N9（2/28,7.1%）,inter-peak latency prolongation in N9-N13（14/28,50%）,N13-N20（19/28,67.9%）,disappearance of wave N20（1/28,3.6%）.Conclusion The detection of MN-SEP in MMA reveals the abnormality of conductive function in nervous system and is a useful method in clinic.