Early diagnosis of diabetic small fiber neuropathy by disturbed cold perception.

In diabetes mellitus, polyneuropathy is an important complication and should be diagnosed as early as possible in order to prevent damage to the patient. Determination of warm, cold, and heat pain thresholds enables one to judge small nerve fiber sensitivity. This investigation was carried out to determine which parameters best predict such alterations. Using a "Marstock" Thermostimulator, 26 diabetics and 32 healthy subjects were stimulated behind both medial malleoli. At three different rates of temperature rise, repeated warm, cold, and heat pain threshold determinations were performed. The variability of intraindividual threshold ranges was noted. While heat pain determinations were not useful, determination of cold perception, at a moderate rate of temperature change, proved to be the most reliable indicator of small fiber lesions. Cold thresholds as well as their intraindividual ranges were most often impaired. The importance of this clinical investigatory method is discussed with respect to the importance of early prophylaxis of complications such as trophic lesions.