Diabetic somatic neuropathies.

SECTION 1: INTRODUCTION — The neuropathies are among the most common of the long-term complications of diabetes, affecting up to 50% of patients (1–4). Their clinical features vary immensely, and patients may present to a wide spectrum of specialties, from dermatology to podiatry, for example, or from urology to cardiology. Neuropathies are characterized by a progressive loss of nerve fibers, which may affect both principle divisions of the peripheral nervous system. This review will focus on the somatic neuropathies; those affecting the autonomic division were recently reviewed by Vinik et al. (5). There is increasing evidence that measures of neuropathy, such as electrophysiology and quantitative tests, are predictors of not only end points, including foot ulceration, but also of mortality (6). The epidemiology and natural history of diabetic neuropathy (DN) remain poorly defined, partly because of poor patient selection and the variable criteria for what constitutes a diagnosis of DN. These aspects, as well as the pathogenesis of DN, will be covered in detail in this review. Studies have confirmed the major contribution of prolonged hyperglycemia in the etiopathogenesis of neuropathy and neuropathic pain (7–10), and this and other putative mechanisms will be discussed. The clinical features, diagnosis, and management of the focal and multifocal neuropathies will be described. A major portion of this review will discuss the clinical features, assessment, and management of the patient with the most common form of DN, diabetic distal sensory polyneuropathy (DPN). The late sequelae of DPN and their prevention will also be described. Finally, practical guidelines for the screening of DPN in clinical practice will be provided. For further details on this topic, please refer to recent reviews (11– 18).