冰试验诊断重症肌无力上睑下垂的价值

Value of ice test in diagnosis of myasthenia gravis

目的观察冰试验在重症肌无力(MG)上睑下垂诊断中的价值。方法对32例MG上睑下垂患者和33例非MG上睑下垂患者进行冰试验和休息试验,MG上睑下垂患者另行新斯的明实验。所有接受检查者均在同一天交替进行冰试验和休息试验2次,MG患者在接受冰试验和休息实验后行新斯的明实验。由两名不知道其临床诊断的观察者在试验前后用精确度为0.5mm的20mm钢尺测量上下睑缘中点之间的宽度,以同一受检者两次冰试验或休息试验前后睑裂宽度之差的平均值为上睑下垂改善程度。结果冰试验和休息试验均能改善部分MG上睑下垂,但对非MG上睑下垂无改善,两者的特异度均为100%。冰试验比休息试验能更大程度的改善MG上睑下垂,具有更高的灵敏度(78%)。对于完全性上睑下垂,冰试验亦能有效的改善其睑裂宽度。与新斯的明试验相比,冰试验敏感性略低,但冰试验检查时间短,无需注射,避免了注射带来的不适,而且无任何毒副作用。结论冰试验是诊断MG上睑下垂的一种简单、安全且灵敏度和特异度较好的检查手段,有较好的临床应用价值。

Objective To investigate the value of ice test in the diagnosis of ptosis of myasthenia gravis（MG）. Methods A total of 32 patients with myasthenic ptosis and 33 with nonmyasthenic ptosis underwent ice and rest test which were performed alternately twice within 1 day on each patient. Besides, neostigmine test was performed on the patients with myasthenic ptosis after ice and rest test. Two observers who didn＇t know the clinical diagnosis were asked to evaluate the improvement of eyelid elevation by measuring the width between the midpoints of upper and lower eyelid with a 20 mm steel rule （precision of 0. 5 mm）. The average of margin of palpebral-fissure width after double ice or rest tests subtracted from the one before the tests in one patient was the standard of the improvement of eyelid elevation. Results lee and rest test improved myasthenie ptosis but not nonmyasthenie ptosis with the specificity of 100% in both of the tests. In addition, ice test improved myasthenie ptosis more effectively with a higher sensitivity of 78%, and it could also improve the palpebral-fissure width in paitents with complete myasthenie ptosis apparently. Compared with the neostigmine test, ice test had lower sensitivity, cost shorter time, didn＇t need injection which avoided the discomfort, and had no side effects. Conclusion Ice test is a simple and safe means with high sensitivity and specificity to diagnose myasthenie ptosis, which is valuable in clinical application.