Evidence of small-fiber neuropathy in neurofibromatosis type 1

Muscle Nerve. 2019 Dec;60(6):673-678. doi: 10.1002/mus.26687. Epub 2019 Sep 12.

Abstract

Introduction: Large-fiber neuropathy is rare in neurofibromatosis type 1, but small-fiber neuropathy has not been studied.

Methods: Patients with neurofibromatosis type 1 underwent nerve conduction studies for large-fiber assessment. Small-fiber tests included quantitative thermal thresholds, laser Doppler flare imaging, intraepidermal nerve fiber density, and corneal nerve fiber length.

Results: Of the 52 patients enrolled, 31 (60%) were female and the mean age was 33.0 ± 12.3 years. Four (8%) patients had abnormal nerve conduction studies. Small-fiber tests were frequently abnormal: thermal thresholds in 7 (13%); laser Doppler flare imaging in 10 (19%); intraepidermal nerve fiber density in 11 (22%); and corneal nerve fiber length in 27 (52%). The mean corneal nerve fiber length was below normative level (10.1 ± 2.7 mm/mm3 ).

Discussion: Small-fiber neuropathy may be common in neurofibromatosis type 1, and should be investigated in symptomatic patients.

Keywords: NF1; confocal corneal microscopy; intraepidermal nerve fiber density; small-fiber neuropathy.

MeSH terms

  • Adult
  • Cornea / innervation
  • Electrodiagnosis
  • Female
  • Humans
  • Intravital Microscopy
  • Laser-Doppler Flowmetry
  • Male
  • Microscopy, Confocal
  • Middle Aged
  • Neural Conduction / physiology*
  • Neurofibromatosis 1 / complications
  • Neurofibromatosis 1 / physiopathology*
  • Sensory Thresholds
  • Skin / blood supply
  • Skin / pathology
  • Small Fiber Neuropathy / etiology
  • Small Fiber Neuropathy / physiopathology*
  • Thermosensing
  • Vasodilation
  • Young Adult