肘肌重复频率刺激对重症肌无力的诊断价值

Repetitive Stimulation of Anconeus Muscle in Diagnosis of Myasthenia Gravis

目的探讨肘肌重复神经刺激（ＲＮＳ）对重症肌无力的诊断价值。方法以小指展肌ＲＮＳ缺血加强试验为对照，测定了重症肌无力２７例及正常人２１例的肘肌ＲＮＳ。结果正常对照组，肘肌ＲＮＳ疲劳前电压平均降低１．６７±１．６６％，最大降低值为８％；疲劳后降低２．６７±２．０５％，最大降低值为７％。重症肌无力组疲劳前测试１３／２７例（４８％）阳性（电压降低≥１０％），疲劳后阳性率为１８／２７例（６６．７％）；而同组患者３／２３例（１３％）小指展肌ＲＮＳ缺血加强试验阳性。卡方检验两种方法阳性率有极显著性差异（χ２＝１４．６６，Ｐ＜０．００１）。结论肘肌ＲＮＳ方法简便，敏感，患者不适感轻。

Objective Repetitive nerve stimulation of anconeus muscle(anconeus RNS) was explored in diagnosis of myasthenia gravis.Methods As compared with abductor digiti minimi(ADM) muscle, anconeus RNS was conducted on 27 patients with myasthenia gravis and 21 control subjects. Results All of the control subjects were negative (amplitude reduce <8%) before or after efforts with anconeus RNS; In the myasthenia gravis group, 13 patients(48%) were positive(amplitude reduce>10%) before effort and 18 patients ( 66.7 %) positive after effort. In same myasthenia gravis group,RNS of ADM in 3/23 (13%) patients were positive after ischemic blood. Anconeus RNS was more sensitive than ADM(χ 2= 14.66 ,P< 0.001 ).Conclusion Anconeus RNS is a simple, sensitive and practicable method for diagnostic myasthenia gravis or estimation of neuromuscular function.