title: Motor nerve conduction study and muscle strength in newly diagnosed POEMS syndrome.
abstract: BACKGROUND
  Mixed demyelination and axonal loss are electrophysiological features of polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome. It is unclear whether the demyelination and axonal loss occur concurrently.
  
  
  METHODS
  Electromyography was performed in 37 patients with newly diagnosed POEMS syndrome. Compound muscle action potential (CMAP) amplitude, distal motor latency, motor conduction velocity (MCV), and spontaneous activity were collected. Muscle strength was measured according to the Medical Research Council (MRC) scale.
  
  
  RESULTS
  MCV decreased in all nerves with decreased CMAP amplitude and in 93% of nerves with normal amplitude. CMAP amplitude decreased in 54% of nerves with decreased MCV and was normal in all nerves with normal MCV. MCV deceased in 95% of nerves with normal MRC. Abnormal spontaneous activity was detected in 32% of upper limb muscles.
  
  
  CONCLUSIONS
  Demyelination may be the main manifestation in POEMS neuropathy at an early stage, and axonal loss may be secondary to demyelination as the disease progresses.
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, 100730, Beijing, China.
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Liu
authors.forename: Zhangyu
authors.initials: Z
authors.lastname: Zou
authors.forename: Yuzhou
authors.initials: Y
authors.lastname: Guan
authors.forename: Jian
authors.initials: J
authors.lastname: Li
authors.forename: Daobin
authors.initials: D
authors.lastname: Zhou
authors.forename: Liying
authors.initials: L
authors.lastname: Cui
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000368:Aged; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology*; D016878:POEMS Syndrome / Q000175:diagnosis* / Q000503:physiopathology*; D012720:Severity of Illness Index; D013127:Spinal Nerves / Q000503:physiopathology*; D018709:Statistics, Nonparametric
keywords: POEMS syndrome; axonal loss; demyelination; motor nerve conduction study; muscle strength