Small-fibre neuropathy can be detected in patients with chronic idiopathic axonal polyneuropathy

Background: The main sensory presenting symptoms of chronic idiopathic axonal polyneuropathy (CIAP) are paraesthesias, numbness and burning pain in the feet. Although these symptoms indicate the involvement of small nerve fibres, clinical analysis or electrophysiological investigations have not yet been studied in detail.

Method: Cardiovascular autonomic tests and cold and heat pain perception threshold tests were performed in 10 patients with CIAP, 10 patients with diabetes mellitus (DM) and 10 healthy volunteers. The results of the DM group were used to see whether the tests were able to detect small-fibre neuropathy in patients with diabetes and pain.

Results: Quantitative sensory threshold and autonomic tests showed more frequent abnormal test results in the patients compared to the healthy control group. The proportion of abnormal test results reached significance for the deep breathing tests in both patient groups and for the cold threshold and heat pain test in patients with CIAP. The spectral analysis of RR intervals showed a significant decrease in the high frequency in both patients with DM and CIAP.

Conclusion: The results of this study demonstrated that small-fibre neuropathy can be detected in patients with CIAP.