• Barbara Namer, Stefan Pfeffer, Hermann O Handwerker, Martin Schmelz, and Andreas Bickel.
• Department of Physiology and Pathophysiology, University of Erlangen, Universitätsstr. 17, 91054, Erlangen, Germany. namer@physiologie1.uni-erlangen.de
• Muscle Nerve. 2013 Mar 1; 47 (3): 357-63.

IntroductionObjective diagnosis of small fiber impairment is difficult.MethodsWe 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.ResultsIn 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.ConclusionsBoth 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.Copyright © 2012 Wiley Periodicals, Inc., a Wiley company.

37 keywords...

hide…