[Pathogenesis of diabetic neuropathies]

There are two types of diabetic neuropathy: on the one hand, mononeuritis and, on the other hand, the symmetric polyneuropathy with a glove and stocking distribution and autonomic polyneuropathy. Mononeuritis (or mononeuritis multiplex) seems to be the result of ischaemia due to intrinsic or extrinsic (altered coagulability) vascular disease. Polyneuropathy is probably due to metabolic factors related to chronic hyperglycaemia: abnormal nerve energy metabolism, impaired axonal transport, increased activity of the sorbitol pathway, non-enzymatic nerve protein glucosylation and abnormal myo-inositol metabolism. The respective roles of these different factors in the pathogenesis of polyneuropathy are discussed.