Background
s and objectives: POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes)syndrome is the rare cause of polyneuropathy. Although the polyneuropathy is essential for the diagnosis of the disease,the pattern of electrodiagnostic abnormalities has not been characterized in detail. The purpose of this study was to elucidatethe features of nerve conduction abnormalities in POEMS syndrome. Methods: We reviewed the medical recordsand nerve conduction studies (NCS) of 12 consecutive patients with POEMS. Results: A total of 68 motor and 46 sensorynerves were examined. Compound muscle action potentials (CMAPs) and sensory nerve action potentials wereabnormally attenuated or not elicited in majority of motor and sensory nerves (80.88% in motor, and 82.6% in sensorynerves). Frequency of the nerves with no potential was significantly higher in lower limbs than in upper limbs (p<0.01in both motor and sensory nerves), and CMAP amplitude was more reduced in lower limbs than in upper limbs(p<0.01). Conduction slowing was very frequently observed with 95% and 76% of motor and sensory nerves, respectively,having the abnormally reduced values of conduction velocity. Distal motor latencies were abnormally prolongedin 75% of motor nerves, and terminal latency indices were significantly higher in patients than in normal controls (p <0.05). Conduction block was observed only in 5% of motor nerves. Conclusions: NCS in POEMS syndrome showedcharacteristic patterns, in which conduction abnormalities were more frequently and severely affected in the lowerlimbs, and more predominantly in the intermediate nerve segments than in the distal portions. The recognition of thesecharacteristic patterns may be helpful in early diagnosis of polyneuropathy in POEMS syndrome.
