Polyneuropathies are a heterogeneous group of diseases that can be caused both by a primary lesion of peripheral nerves, and secondarily, against the background of various somatic diseases. The most common cause of chronic polyneuropathy is distal symmetrical diabetic polyneuropathy. In clinical practice, it is important to be aware of dysimmune polyneuropathy, such as Guillain Barré syndrome, chronic inflammatory demyelinating polyneuropathy, and paraproteinemic polyneuropathy, which lead to severe motor impairment and disability in patients. Identification of the cause of polyneuropathy requires real art, which includes knowledge of the clinical, electrophysiological picture and variants of the course of the disease, as well as a wide range of conditions leading to their development. Timely diagnosis of polyneuropathies and early assignment of etiological and pathogenetic therapy reduce the risk of developing irreversible changes in peripheral nerves caused by axonal degeneration. In the treatment of polyneuropathy of various origins, a special place is occupied by B vitamins, which have a neurotropic effect. Cyanocobalamin is a pathogenetic therapy in patients with diabetes who take metformin for a long time and who developed polyneuropathy due to vitamin B12 deficiency. In one patient, a combination of several variants of polyneuropathies is possible. The article presents a clinical case of a patient with type 1 diabetes mellitus (DM) who developed dysimmune chronic inflammatory demyelinating polyneuropathy (CIDP) associated with DM on the background of distal symmetrical painless diabetic polyneuropathy after a COVID- 19 infection. A feature of the development of CIDP was the acute onset of the disease. Variants of the clinical picture, ENMG criteria, as well as features of treatment, the effectiveness of therapy and the prognosis of CIDP in patients with DM are discussed.
