ABSTRACT
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; χ2=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; χ2=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; χ2=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=1 077.500, 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.
ABSTRACT
Objective To describe the repetitive nerve stimulation ( RNS) in anti-muscle specific tyrosine kinase (anti-MuSK) receptor antibody positive myasthenia gravis (MG), and compare with anti-acetylcholine receptor ( AChR ) positive myasthenia gravis , to figure out characteristics of anti-MuSK receptor MG.Methods We analyzed clinical and RNS data of nine anti-MuSK receptor MG and 19 age-and sex-matched anti-AChR MG.RNS was performed to the abductor digiti minimi , orbicularis oculi or musculus frontalis and trapezius .Results In anti-MuSK receptor MG , abnormal RNS in facial nerve was seen in 6/9 and in trapezius was 5/9, in limbs was 0.In anti-AChR MG, abnormal RNS in facial nerve was seen in 13/19, in trapezius was 18/19 and in limbs was 7/19.Abnormal in any of three parts was 8/9 and 19/19 in anti-MuSK receptor MG and anti-AChR MG, respectively.The RNS decrementing was more obvious in facial nerve in anti-Musk receptor MG than in anti-AChR MG.Negative prostigmin test was independently associated with anti-MuSK receptor MG (OR=4.25,95% CI 2.19 -15.25, P=0.015). Conclusions Abnormal RNS in any of three parts is more pronounced in anti-AChR MG compared with anti-MuSK receptor MG.RNS decrementing in facial nerve is more obvious in anti-AChR MG.Negative prostigmin test can aid in early suspicion in anti-MuSK receptor MG.
ABSTRACT
Objective To describe the repetitive nerve stimulation ( RNS) in anti-muscle specific tyrosine kinase (anti-MuSK) receptor antibody positive myasthenia gravis (MG), and compare with anti-acetylcholine receptor ( AChR ) positive myasthenia gravis , to figure out characteristics of anti-MuSK receptor MG.Methods We analyzed clinical and RNS data of nine anti-MuSK receptor MG and 19 age-and sex-matched anti-AChR MG.RNS was performed to the abductor digiti minimi , orbicularis oculi or musculus frontalis and trapezius .Results In anti-MuSK receptor MG , abnormal RNS in facial nerve was seen in 6/9 and in trapezius was 5/9, in limbs was 0.In anti-AChR MG, abnormal RNS in facial nerve was seen in 13/19, in trapezius was 18/19 and in limbs was 7/19.Abnormal in any of three parts was 8/9 and 19/19 in anti-MuSK receptor MG and anti-AChR MG, respectively.The RNS decrementing was more obvious in facial nerve in anti-Musk receptor MG than in anti-AChR MG.Negative prostigmin test was independently associated with anti-MuSK receptor MG (OR=4.25,95% CI 2.19 -15.25, P=0.015). Conclusions Abnormal RNS in any of three parts is more pronounced in anti-AChR MG compared with anti-MuSK receptor MG.RNS decrementing in facial nerve is more obvious in anti-AChR MG.Negative prostigmin test can aid in early suspicion in anti-MuSK receptor MG.