Axon reflex flare and quantitative sudomotor axon reflex contribute in the diagnosis of small fiber neuropathy
Article first published online: 24 NOV 2012
Copyright © 2012 Wiley Periodicals, Inc., a Wiley company
Muscle & Nerve
Volume 47, Issue 3, pages 357–363, March 2013
How to Cite
Namer, B., Pfeffer, S., Handwerker, H. O., Schmelz, M. and Bickel, A. (2013), Axon reflex flare and quantitative sudomotor axon reflex contribute in the diagnosis of small fiber neuropathy. Muscle Nerve, 47: 357–363. doi: 10.1002/mus.23543
- Issue published online: 23 FEB 2013
- Article first published online: 24 NOV 2012
- Accepted manuscript online: 1 AUG 2012 03:17AM EST
- Manuscript Accepted: 28 JUL 2012
- axon reflex sweating;
- axon reflex erythema;
- axon reflex flare;
- small fiber neuropathy;
- thermal thresholds
Objective diagnosis of small fiber impairment is difficult.
We used the quantitative sudomotor axon reflex test (QSART) and axon-reflex-flare-test in the foot and thigh of 46 patients with peripheral neuropathy to assess C-fiber function in addition to conventional neurography and thermal threshold testing.
In all patients, small fiber impairment was suspected because of abnormal warmth detection thresholds (76% of all tested) and/or pain in the feet. A total of 83% had reduced axon-reflex flare areas and 17% lower QSART scores. Patients with pure small fiber neuropathy had higher rates of reduced flare areas (87.5%) and sweating rates (25.5%). There was no difference between patients with and without pain regarding thermotesting and axon-reflex testing.
Both axon-reflex tests are helpful to identify objectively patients with small fiber impairment. Afferent and efferent C-fiber classes can be impaired differently. These tests detect small fiber impairment, but they cannot differentiate between painful and nonpainful neuropathy. Muscle Nerve 47: 357–363, 2013