Modern approaches to the diagnosis of diabetic polyneuropathy: innovations and prospects

Diabetic neuropathy (DN) is a severe complication of diabetes mellitus, which includes disorders of the sensory, motor and autonomic function of peripheral nerves. According to existing literature, the development of DN is observed in more than half of patients with diabetes mellitus and depends on the degree of its compensation. DN is divided into symmetric (distal sensorimotor polyneuropathy, small fiber polyneuropathy, autonomic neuropathy) and asymmetric (mononeuropathies and radiculoplexopathies). Distal sensorimotor diabetic polyneuropathy is the most common phenotype, which accounts for a third of all existing polyneuropathies and 75—90 % of peripheral nervous system lesions in diabetes mellitus. More than a quarter of patients with DN already at the beginning of the disease suffer from neuropathic pain syndrome, which significantly worsens their quality of life and increases the socioeconomic burden. According to the results of studies published to date, the pathogenesis of the disease is quite complex and multilevel and is determined by the degree of hyperglycemia, the duration of the disease and associated risk factors, among which obesity has the greatest pathogenetic significance. It is important that at the beginning of the disease, damage to the peripheral nervous system is characterized by an asymptomatic course and only the further progression of diabetes mellitus leads to the manifestation of sensitive, autonomic and motor disorders. Excess body weight in these patients significantly enhances, and sometimes is the direct cause of hyperglycemia, since due to the secretion of adipokines, such as adiponectin and leptin, it contributes to an increase in insulin resistance, the progression of metabolic disorders and stimulates inflammation. The connection of peripheral nerves damage in diabetes mellitus with inflammation, one of the most powerful markers of which is Tumor Necrosis Factor-alpha (TNF-alpha), is an important aspect of pathogenesis. In addition to clinical symptoms, scales, electrophysiological and microscopic studies are used to diagnose peripheral nervous system lesions in diabetes. The Sudoscan and Neuropad methods allow for non-invasive determination of vascular motor dysfunction in patients with DN, and the study of biomarkers, such as inflammatory cytokines and neurotrophic factors, is a promising direction for predicting the occurrence and clinical manifestations of DN. An integrated approach to research opens up opportunities for the development of specific methods for diagnosing and treating DN, contributing to improving the quality of life of patients facing this complex problem.