Abstract. The Nowadays the thyroid pathology is known to be one of the most widely spread ones in the structure of endocrine diseases [2,15]. Recently the increase of occurrence of autoimmune thyropathies, mostly followed by the development of hypothyroidism has been observed in Ukraine and other countries. At the same time, the number of surgeries for nodular forms of goiter, tumors, etc., frequently resulting in hypothyroidism, growths as well. The results of epidemiological studies show, that the overall prevalence of manifested hypothyroidism in the population is 0.2-2 %, subclinical one -7-10 % among women and 2.3 % among men, and morbidity rates are continuously rising every year [15]. There are more than 98 hundred people with this disease, officially registered in Ukraine at the beginning of 2016 [16].At its early stages the disease is accompanied by a wide range of neurological syndromes, which often dominate in the clinical manifestation of the disease and involve practically all levels of the nervous system [7,11]. However, despite a long history of detection of interconnections between the thyroid and neurological pathologies, the study of damaging mechanisms for the nervous system in hypothyroidism still remains a topical issue of contemporary neuroendocrinology.Deficiency of thyroid hormones in the body leads to disorders of water and electrolyte balance, protein, lipid, carbohydrate metabolisms, causing morphologicalfunctional and biochemical changes in various organs and systems [2,15]. Hypothyroidism is accompanied by disturbed synthesis of neurotransmitters, increased levels of blood lipids, lowering the energy potential of the cells, the activation of free radical processes, reduction of synthesis of a nitric oxide and endothelial dysfunction, disturbance of blood microcirculation disorders, imbalance of proinflammatory cytokines and adipocytokines, etc. [18]. A dramatic inhibition of energy and anabolic processes, typical for hypothyroidism, promotes an organic damage of the nervous system [22].Hypothyroid neurological disorders are various and numerous [14,15]. Marked changes in the peripheral nervous system, typical for hypothyroidism, are implemented in the development of pseudomyotonic and pseudomyasthenic syndromes, radiculopathies, polyneuritis, tunnel neuropathies, and polyneuropathies as well. The latter are found in 18-72 % of patients with hypothyroidism [7,11,22], and symptoms of polyneuropathy can develop not only in manifested hypothyroidism, but also in subclinical one [30]. However, there is no consensus concerning the pathogenesis of hypothyroid polyneuropathy (PNP), correlation between the degree of its manifestation and hormonal status, state of the neuromuscular system during the compensation of the underlying disease. Thus, indicating a direct connection between the level of thyroid hormones, the degree of hypothyroidism compensation and polyneuropathy symptoms, some researchers believe that all clinical, electroneuromyographic and histopathological changes in patients w...
