例1 女、18岁,92年6月始相继出现双睑下垂、四肢无力、言语不清和吞咽困难。作新斯的明试验阳性。诊为重症肌无力,给以强的松每日60mg,一个月内病情一度好转,但一个月后病人上述症状加重,并出现四肢肌肉萎缩,无力及萎缩以双下肢近端为重。四肢肌力3级,锥体束征阴性,CPK 40IU/L.EMG示肌源性损害。病肌活检示选择性Ⅱ型肌纤维萎缩,肌核密集,无炎性细 Case 1 female, 18 years old, 92 years ago, there have been double eyelid ptosis, weakness, verbal illnesses and difficulty swallowing. Neostigma test positive. The diagnosis of myasthenia gravis, given prednisone 60mg daily, the condition was improved within a month, but one month later the patient’s symptoms worsened, and limb muscle atrophy, weakness and atrophy to the proximal lower extremity. Limb muscle strength 3, cone sign negative, CPK 40IU / L.EMG showed myogenic damage. Sick muscle biopsy showed selective type Ⅱ muscle fiber atrophy, muscle-intensive, no inflammatory thin