POEMS综合征患者临床与节段神经传导速度研究

Motor nerve conduction and clinical characteristics of POEMS syndrome

目的总结POEMS综合征患者早期临床及神经传导损害的表现特点,探索节段传导速度在POEMS综合征疾病诊断中的应用价值。方法对北京协和医院2009年9月至2019年6月收治的73例首次确诊为POEMS综合征患者的临床特点进行总结,结合患者正中神经、尺神经、胫神经以及腓神经节段运动神经传导、感觉神经传导检测数据进行分析,并纳入了27名正常对照者。分析指标主要包括临床表现、体征、节段运动神经传导和感觉神经传导。节段神经传导分析指标包括:运动末端潜伏期(distal motor latency,DML),复合肌肉动作电位(compound muscle action potential,CMAP)波幅,正中神经肘-腕速度、腋-肘速度,尺神经肘下-腕速度、肘上-肘下速度、腋-肘上速度、胫神经踝-腘窝速度、腓神经踝-腓骨小头速度,感觉神经传导指标包括:波幅、速度、正中神经远端潜伏期指数(terminal latency indices,TLI),并观察有无神经传导阻滞。结果本组患者中以周围神经损害表现起病的有32例,占43.8%(32/73),其中下肢麻木者占81.3%(26/32)。存在肢体麻木的POEMS综合征患者感觉神经传导检查均异常,不存在感觉症状的患者有9.5%(7/73)存在感觉神经传导的异常。此外,运动波幅降低对应临床肌力下降及运动功能障碍。在POEMS综合征患者中,下肢的运动神经传导较上肢更容易受累且程度更重:下肢与上肢的CMAP消失比例分别为47.6%(112/235)与2.8%(7/252;χ^2=133.698,P<0.01);感觉神经传导较运动神经传导损害更严重:感觉与运动波幅消失比例分别为43.0%(141/328)与24.4%(119/487;χ^2=31.053,P<0.01);运动神经传导速度减慢较波幅降低更普遍:运动神经传导速度减慢比例为88.7%(432/487),波幅降低比例为52.8%(257/487;χ^2=151.905,P<0.01)。POEMS综合征患者的正中、尺神经DML均较对照组延长[正中神经:4.4(3.7,5.0)ms与3.2(3.0,3.5)ms,U=854.000,P<0.01;尺神经:3.1(2.7,3.8)ms与2.5(2.2,2.7)ms,U=1077.500,P<0.01]。POEMS综合征患者的正中神经TLI明显高于正常对照者(0.40±0.11与0.35±0.06,t=3.466,P=0.001),而前臂段与上臂段神经传导速度差异无统计学意义。结论POEMS综合征患者以神经损害起病较为常见,感觉神经损害常为首发临床表现,患者早期的神经损害下肢重于上肢,感觉神经重于运动神经。POEMS综合征患者节段运动神经传导结果提示神经髓鞘损害早于轴索损害,近端损害稍重于远端损害,且较少出现传导阻滞,这些节段神经传导特点可为POEMS综合征诊断提供更多证据。

Objective To summarize the clinical characteristics and nerve conduction damage in patients with early POEMS syndrome,and to explore the value of segment nerve conduction velocity in the diagnosis of POEMS syndrome.Methods A total of 73 patients with POEMS syndrome and 27 healthy controls in Peking Union Medical College Hospital from September 2009 to June 2019 were recruited in this study.The motor and sensory nerve conduction characteristics of median,ulnar,tibial,and peroneal nerves and the clinical features of the participants were analyzed.The analysis parameters included:(1)distal motor latency(DML),compound muscle action potential(CMAP);(2)the median velocity from elbow to wrist,the median velocity from axillary to elbow,the ulnar velocity from the site below elbow to wrist,the ulnar velocity from the site above elbow to below elbow,the ulnar velocity from axillary to the site above elbow,the tibial velocity from ankle to knee,the peroneal velocity from ankle to fibulae capitulum;(3)sensory nerve conduction velocity and amplitude of these nerves;(4)terminal latency indices(TLI)of median;(5)motor nerve conduction blocks.Results Peripheral nerve damages were the initial symptoms in thirty-two patients in this group,accounting for 43.8%(32/73),and 81.3%(26/32)of these patients only showed numbness in lower extremities.All POEMS syndrome patients with numbness had abnormal sensory nerve conduction,and 9.5%(7/73)of patients without sensory symptoms also had abnormal sensory nerve conduction.On the other hand,the decrease of CMAP amplitude corresponded to clinical muscle strength decline and motor dysfunction.In the patients with POEMS syndrome,motor nerve conduction in the lower limbs were more likely to be affected and the damages were more severe than in the upper limbs:the proportion of CMAP disappearance in the lower limbs and upper limbs was 47.6%(112/235)vs 2.8%(7/252;χ^2=133.698,P<0.01).Sensory nerve conduction damage was more severe than motor nerve conduction:the proportion of amplitude disappearance in sensory and motor conduction was 43.0%(141/328)vs 24.4%(119/487;χ^2=133.698,P<0.01).The slowing of motor nerve conduction velocity was more common than the decrease of CMAP amplitude:the rate of slowing down of motor nerve conduction was 88.7%(432/487),and the rate of decrease of amplitude was 52.8%(257/487;χ^2=151.905,P<0.01).The DML of median and ulnar nerve in the POEMS syndrome group was longer than that in the control group(median nerve:4.4(3.7,5.0)ms vs 3.2(3.0,3.5)ms,U=854.000,P<0.01;ulnar nerve:3.1(2.7,3.8)ms vs 2.5(2.2,2.7)ms,U=1077.500,P<0.01).The TLI of median nerve in patients with POEMS syndrome was significantly higher than that of healthy controls(0.40±0.11 vs 0.35±0.06,t=3.466,P=0.001).There was no statistically significant difference in nerve conduction velocity between the forearm segment and the upper arm segment in the POEMS group.Conclusions Neurological damages were common in patients with POEMS syndrome with sensory nerve damage often being the initial clinical manifestation.In patients with POEMS syndrome,the nerve damage in the lower limbs was more severe than in the upper limbs,and sensory nerve damage was more severe than motor nerve damage.Segmental motor nerve conduction results suggested that demyelination damage occurred earlier than axonal damage,and proximal lesions were slightly heavier than distal lesions.No conduction block was detected in these patients.These characteristics of segmental nerve conduction can provide more evidence for clinical diagnosis of POEMS syndrome.