Evaluation of somatic and autonomic small fibers neuropathy in diabetes.

The relationship between somatic and autonomic neuropathy was assessed in the feet of 30 diabetic patients. Somatic small fiber function was evaluated by the thermal threshold test for cold (A delta fibers) and warmth (C fibers). Telethermography and transcutaneous oxygen tension were used to investigate the autonomic control of peripheral circulation. Autonomic neuropathy caused the opening of arteriovenous anastomosis, which was revealed through an elevation of the feet's temperature and a low transcutaneous oxygen tension. The association of the opening of the arteriovenous anastomosis and the perturbation of the thermal threshold test established a relationship between the dysfunction of the autonomic and the somatic fibers.