Lambert-Eaton肌无力综合征6例临床与电生理特点分析

Analysis of 6 patients with Lambert-Eaton myasthenic syndrome: clinical and electrophysiological features

目的探讨Lambert-Eaton肌无力综合征(LEMS)的临床及电生理特点。方法分析2002-2011年作者医院诊断的6例LEMS患者的临床资料及神经电生理检查结果。结果 6例患者起病年龄34～65岁(中位数53岁),病程0.5～35个月(中位数4个月)。4例患者最初诊断为重症肌无力。5例患者伴恶性肿瘤。6例患者均以肢体近端无力起病。5例患者腱反射减低或消失。3例患者伴口干、眼干等自主神经症状。5例患者行新斯的明试验,其中4例阳性。6例患者均行神经电生理检查,共9次。5例行针极肌电图检查共6次,其中结果显示肌源性改变3次,神经源性改变2次,正常1次。5例行7次神经传导速度检查,全部提示复合肌肉动作电位明显减低。6例共行9次重复神经电刺激(RNS)检查,全部提示高频刺激波幅递增。结论掌握LEMS的临床及电生理特征有助于及时正确诊断。

Objective To investigate the clinical and electrophysiological features of Lambert-Eaton myasthenic syndrome （LEMS）. Methods Six LEMS patients admitted to our hospital from 2002 to 2011 were reviewed. Clinical and electrophysiological characteristics were analyzed. Results The age range of the patients was 34-65 years old with the median of 53 years old, time from onset to diagnosis was 0.5-35 months with the median of 4 months. Four patients were primary diagnosed as myasthenia gravis. Tumor was found in 5 patients. All of the 6 patients presented with proximal weakness. Five patients had decreased tendon reflexes. Three patients had dryness of mouth and eyes. The neostigmine test was positive in 4 of the 5 patients tested. Nine electrophysiological tests were performed in these 6 patients. In the 6 needle electromyography （EMG） examinations, 3 showed myopathic changes, 2 showed neuropathic changes, and 1 showed normal EMG. Seven nerve conduction studies all showed significantly decreased compound muscle action potential. Nine repetitive nerve stimulation （RNS） all demonstrated amplitude increment〉100%. Conclusions Awareness of the clinical and electrophysiological features of LEMS can improve diagnosis.