伴肌萎缩重症肌无力4例分析并文献复习

Myasthenia gravis associated with muscular atrophy:analysis of 4 cases and review of literature

目的探讨伴肌萎缩重症肌无力(myasthenia gravis,MG)患者的临床特征、抗体及电生理特点,提高对此少见疾病的认识。方法回顾性分析作者医院2003—2016年收治的伴肌萎缩MG患者4例的临床资料,分析其临床特征、抗体、神经电生理检查、治疗及预后特点。结果 4例患者病程中出现不同程度的肌肉萎缩,1例为手肌(左侧大鱼际肌、小鱼际肌及第一骨间肌)萎缩,3例为舌肌萎缩(其中1例同时伴面肌萎缩);抗体检查显示乙酰胆碱受体抗体(AChR-Ab)阳性3例,1例为抗骨骼肌特异性受体酪氨酸激酶抗体(MuSK-Ab)阳性。4例患者低频重复神经刺激波幅均可递减,高频刺激波幅未见明显递增。伴手肌萎缩MG患者针极肌电图检查结果提示神经源性损害。结论伴肌肉萎缩MG较罕见,MuSK-Ab、AChR-Ab阳性MG患者均可出现肌肉萎缩,其机制有待进一步明确;早期行神经电生理检查、AChR-Ab及MuSK-Ab测定有助于明确诊断。

Objective To discuss the clinical characteristics,antibody and electrophysiological characteristics of patients with myasthenia gravis（MG）accompanied by muscle atrophy and to improve the understanding of this rare disease.Methods The clinical data of 4 patients with MG accompanied by muscle atrophy treated in our hospital from 2003 to 2016 were retrospectively analyzed.The clinical features,antibody states,neuroelectrophysiological examination and prognosis were analyzed.Results Four patients showed varying degrees of muscular atrophy during the course of their disease,one case had the hand muscle（the left thenar muscle,the hypothenar muscle and the first interosseous muscle）atrophy,three cases had tongue muscle atrophy,of which 1 case accompanied by facial muscle atrophy;antibody test showed that 3 cases were positive for acetylcholine receptor antibody（AChR-Ab）and 1 case was positive for anti-skeletal muscle specific receptor tyrosine kinase antibody（MuSK-Ab）.The amplitude during low-frequency repetitive nerve stimulation decreased in all 4 patients,and the amplitude during high-frequency stimulation did not significantly increased.Needle EMG examination in the MG patient with hand muscle atrophy suggested neurogenic damage.Conclusions Muscle atrophy in MG is rare,and muscular atrophy may occur in MG patients with MuSK-Ab or AChR-Ab.The mechanism needs to be further clarified.Early neuroelectrophysiological examination,AChR-Ab and MuSK-Ab tests can help confirm the diagnosis.