一氧化二氮滥用致周围神经病患者的神经电生理特点

Neuroelectrophysiological characteristics of peripheral neuropathy patients caused by nitrous oxide abuse

目的探讨一氧化二氮(N_2O)滥用致中毒性周围神经病患者的神经电生理特点。方法回顾性分析10例N_2O滥用导致的周围神经病患者的神经电生理(神经传导速度测定、针极肌电图检查、F波、H波)特点。结果与正常参考值相比,上、下肢近端所检运动纤维及上、下肢远端所检运动纤维异常率分别为0、40%、37.5%、90%,异常运动纤维远端潜伏期(MLAT)分别延长0、36.1%、17.8%、37.2%,复合肌肉动作电位(CMAP)分别下降0、88.6%、31.4%、64.5%;上、下肢远端运动纤维运动传导速度测定(MCV)分别延长10.4%、16.4%;上、下肢远端感觉纤维异常率分别为7.5%、80%;上、下肢异常感觉纤维波幅分别下降7.5%、79.4%,感觉传导速度测定分别延长0、8.6%;上、下肢F波异常率分别为0、50%;双下肢H波异常率100%;双上肢针极肌电图异常率30%,双下肢针极肌电图异常率90%(P<0.05)。结论N2O滥用致周围神经损害可同时累及运动纤维与感觉纤维,以轴索损害为主,下肢受累为著,远端受累较近端受累为重,具有长度依赖性及对称性。针极肌电图可早期出现中-多量失神经电位,大力收缩募集减少,伴或不伴运动单位时限增宽。神经电图提示F波出现率减少或H波波幅降低,伴或不伴潜伏期延长。

Objective To explore the neuroelectrophysiological characteristics of toxic peripheral neuropathy caused by the abuse of nitrous oxide(N2O).Methods Retrospective analysis of the neuroelectricity of 10 patients with peripheral neuropathy caused by N2O abuse.Features of physiology(measurement of nerve conduction velocity,needle electromyography,F wave,H wave).Results Compared with the normal reference value,the motor fiber detected in the proximal end of the upper limb and the lower limb;motor fibers detected at the distal end of the upper limb and the lower limb were 0,40%,37.5%,90%;the distal latency(AT)of the abnormal motor fibers detected was longer than normal by 0,36.1%,17.8%,and 37.2%,respectively;compound muscle action potential(CMAP),they were decreased by 0,88.6%,31.4%,and 64.5%;the detected motor fiber velocity of the upper and lower extremities(MCV)was 10.4%longer.The abnormal rate of the sensory fibers and the sensory fibers detected at the distal end of the lower limb were 7.5%and 80%,respectively.The abnormal sensory fiber amplitudes of the upper and lower limbs examined were decreased by 7.5%and 79.4%;the measurement of sensory conduction velocity was extended by 0 and 8.6%.Upper and lower limb F wave abnormal rate 0,50%;H-wave abnormality rate of both lower limbs is 100%.The abnormal rate of needle pole electromyogram detected by both upper limbs was 30%,and the abnormal rate of needle pole electromyogram detected by both lower limbs was 90%(P<0.05).Conclusion Peripheral nerve damage caused by N2O abuse can involve motor fibers and sensory fibers at the same time,mainly axonal degeneration,can be accompanied by demyelinating damage,lower limb damage is more severe than upper limbs heavily affected,the distal involvement is more severe than the proximal involvement,with length dependence and left-right symmetry.EMG can show early-to-large amount of denervation potential,reduce vigorous contraction and recruitment,and widen the time limit with or without motor unit.The electroencephalogram indicates that the frequency of F waves is reduced or H waves decreased,with or without incubation period extension.