Incidence and prevalence of diabetic neuropathy increase with age and increasing duration of diabetes. Evidence supports an ischemic cause for mononeuropathies, but the pathogenesis of polyneuropathy is still uncertain. Mononeuropathies, involving discrete cranial or peripheral nerves, usually resolve spontaneously or respond to therapy. Distal symmetrical polyneuropathy, the most common form of diabetic neuropathy, tends to be progressive and difficult to treat. Autonomic neuropathy occurs as an extension of polyneuropathy in up to 70% of diabetics. Since no organ supplied by the autonomic nervous system is immune.