Neuromyotonia and type I myofiber predominance in amyloidosis

Muscle Nerve. 1996 Oct;19(10):1338-41. doi: 10.1002/(SICI)1097-4598(199610)19:10<1338::AID-MUS12>3.0.CO;2-Q.


A case of amyloidosis presented with neurormyotonia and marked predominance of type I myofibers as documented by biopsy of an enlarged anterior tibialis muscle. This likely represents conversion of type II fibers to type I from continuous neuromyotonic stimulation. This transformation is well described to occur in animal models and this case represents a unique human example. Enlarged muscles likely reflected pseudohypertrophy.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Amyloidosis / complications*
  • Biopsy
  • Electromyography
  • Fasciculation / etiology*
  • Fasciculation / pathology*
  • Female
  • Humans
  • Microscopy, Electron
  • Muscle Fibers, Skeletal / classification
  • Muscle Fibers, Skeletal / ultrastructure*
  • Muscle, Skeletal / pathology
  • Muscle, Skeletal / physiopathology