title: [Neurophysiologic studies of POEMS syndrome and its related diseases].
abstract: OBJECTIVE
  To explore the electrophysiological characteristics of polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin changes (POEMS) syndrome and its related diseases.
  
  
  METHODS
  The electrophysiological characteristics were analyzed retrospectively from June 2000 to June 2013 in patients with POEMS syndrome, monoclonal gammopathy of undetermined significance (MGUS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Electromyography and nerve conduction examinations of median, ulnar, tibial, peroneal and sural nerves were performed.
  
  
  RESULTS
  In patients with POEMS syndrome, the amplitude of compound muscle action potential (CMAP) of tibial and peroneal nerves was lower than that of median and ulnar nerves ((1.02 ± 0.23) vs (2.12 ± 0.30) mV, (P < 0.05) ); compared with patients with CIDP, the amplitude of CMAP for POEMS patients was lower ((2.12 ± 0.30) vs (3.94 ± 0.52) mV, (1.02 ± 0.23) vs (3.65 ± 0.57) mV) (P < 0.05) while terminal latency indices (TLI) was higher ((0.41 ± 0.13) vs (0.22 ± 0.01), (0.45 ± 0.16) vs (0.24 ± 0.13) ) (P < 0.05) and the occurring rate of conduction block (CB) and temporal dispersion (TD) was lower (P < 0.05). Compared with MGUS patients, the amplitude of CMAP for POEMS patients was lower ((2.12 ± 0.30) vs (3.81 ± 0.83) mV, (1.02 ± 0.23) vs (3.82 ± 0.63) mV) (P < 0.05) ; sensory conduction velocity of POEMS patients was faster ((33 ± 5) vs (20 ± 3) m/s, (28 ± 4) vs (18 ± 3) m/s)(P < 0.05)).
  
  
  CONCLUSIONS
  Nerve conduction studies of POEMS syndrome implicate both axonal loss and demyelination.Uniform demyelination is more predominant in nerve trunk rather than distal nerve terminals. CB and TD occur less frequently and axonal loss is length-dependent.
authors.affiliation: Department of Neurology, Peking University Third Hospital, Beijing 100191, China.
authors.forename: Yingsheng
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Neurology, Peking University Third Hospital, Beijing 100191, China.
authors.forename: Hongsong
authors.initials: H
authors.lastname: Song
authors.affiliation: Department of Neurology, Peking University Third Hospital, Beijing 100191, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Neurology, Peking University Third Hospital, Beijing 100191, China. Email: dsfan@sina.com.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Fan
mesh_terms: D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008998:Monoclonal Gammopathy of Undetermined Significance / Q000503:physiopathology; D009431:Neural Conduction; D016878:POEMS Syndrome / Q000503:physiopathology*; D010543:Peroneal Nerve / Q000503:physiopathology*; D020277:Polyradiculoneuropathy, Chronic Inflammatory Demyelinating / Q000503:physiopathology; D012189:Retrospective Studies