低频重复神经电刺激疲劳试验对重症肌无力患者的诊断作用

Diagnostic value of exercise test of low-frequency repetitive nerve stimulation in patients with myasthenia gravis

目的:对重症肌无力(MG)患者行低频重复神经电刺激(RNS)检测中的疲劳试验,阐明疲劳试验对MG患者的诊断价值。方法:收集30例MG患者,对面神经进行静息状态低频RNS检测,并进行疲劳试验,分别疲劳1和2min,在疲劳结束后的即刻、休息1min及2min再进行RNS检测。分析静息及疲劳后不同时间点RNS中复合肌肉动作电位(CMAP)波幅递减百分率的差异。结果:低频RNS疲劳试验各时间点CMAP波幅递减幅度均较静息状态递减幅度明显,30例患者中以疲劳2min后休息1min RNS递减幅度最明显。30例患者中12例患者RNS静息状态下CMAP波幅未见明显递减现象,而疲劳后CMAP波幅递减明显。结论:低频RNS疲劳试验可明显提高MG患者的诊断率,尤其对于静息状态下RNS检测正常的MG患者有效。检测时以疲劳2min后休息1min效果最明显。

Objective To perform the exercise test of low-frequency repetitive nerve stimulation（RNS）in the patients with myasthenia gravis（MG）,and to clarify the diagnostic value of exercise test in the patients with MG.Methods 30 patients with MG were collected.The RNS at rest and exercise test in facial nerve were performed in all patients.Exercise test was performed at fatigue 1min and 2min,then the RNS was performed at the ending of fatigue,1min and 2 min after fatigue,respectively.The decreasing degree of compound muslce action potential（CMAP）amplitude at different time points were analyzed.Results The CMAP amplitudes in exercise test of RNS were decreased significantly when compared with RNS at rest at different time points,especially at fatigue 2 min and rest 1min.Amang 30 patients,12patients had normal RNS at rest,but all of them had abnormal RNS after exercise test.Conclusion Exercise test of RNS has the diagnostic value in the patients with MG,especially in the patients with normal RNS at rest.Fatigue 2min and rest 1min could be considered when performing exercise testof RNS.