Autonomic neuropathy and toe circulation. A prospective study.

Ankle and toe pressure ratios and toe temperature reactions to cold followed by indirect heating were evaluated in 23 diabetic patients with and without autonomic neuropathy (AN) in a first and in a second follow-up study after 5-7 years. In the first study, despite normal blood pressure ratios, AN patients, all with parasympathetic neuropathy, showed a markedly delayed increase in toe temperature after cooling followed by indirect heating. In the second study, most AN patients showed sympathetic neuropathy and had higher toe temperatures before cooling than those without AN. Parasympathetic neuropathy leads to increased sensitivity to cold in toe vessels and sympathetic neuropathy to vasodilation and increased toe temperatures.