Etiology of small-fiber neuropathy

The aim of this study was to evaluate the etiology in a group of 84 patients with painful sensory neuropathy with predominant small-fiber dysfunction (54 men and 30 women, median: 58; range: 25-83 years) recruited from a population of the South Moravian region of the Czech Republic. Involvement of small nerve fibers was verified by abnormal thermal thresholds and/or reduced intraepidermal nerve fiber densities. Motor signs or symptoms or significant clinical signs of sensory large-fiber involvement were exclusionary; 33 patients, however, had sensory nerve conduction abnormalities. For comparison, the prevalence of risk factors was assessed in a group of 47 asymptomatic age- and sex-matched controls (30 men and 17 women, median: 59; range: 29-85 years). The multivariate regression model disclosed that diabetes mellitus (odds ratio [OR] = 4.08), chronic alcoholism (OR = 5.31), and serum cholesterol levels (OR = 4.51) were the only parameters independently associated with small-fiber involvement. No possible etiology was detected in 19 patients (22.6%). In conclusion, the spectrum of risk factors and proportion of idiopathic cases in geographically defined small-fiber polyneuropathy sample is similar to that referred in large-fiber polyneuropathy.