DIAGNOSTIC AND CLINICAL ASPECTS OF NORMOCALCEMIC PARATHYROID HYPERPLASIA AND NON-RENAL SECONDARY HYPERPARATHYROIDISM IN EXPOSED AND NON;EXPOSED TO IONIZING RADIATION INDIVIDUALS (LITERATURE REVIEW AND OWN RESEARCH DATA).

Parathyroids are the key regulators of calcium-phosphorus metabolism. By means of parathyroid hormone they respond to any changes in the serum level of calcium and phosphorus ions and determine the integrity of skeleton, affecting almost all systems and cells where calcium and phosphorus are involved in metabolism and/or signaling.Disorders of parathyroid function are associated with significant complications accompanying secondary hyperparathyroidism. Unfortunately, most medical practitioners and scientists underestimate the impact of parathyroid hormone excess and vitamin D deficiency. Usually, medical practitioners do not prescribe the assay of serum level of parathyroid hormone, which should be done as a screening test, so the disease remains unnoticed for a long time.In fact, the incidence of parathyroid disorders, namely hyperparathyroidism, is almost equal to the incidence of thyroid diseases and is more than 10 % for the entire population, depending on the observation groups (gender, age, exposure to ionizing radiation), as demonstrated in our previous studies. Thus, according to our data, the incidence of parathyroid hyperplasia is 24.3 % (with 50-70 % in children and adolescents) in the state of euparathyroidism, and incidence of normocalcemic hyperparathyroidism is up to 14.3 % in the average population of Ukraine. Today, we see much confusion in publications and available recommendations regarding diagnosis, pathogenesis, and course of parathyroid disease. It is often not taken into account that the strain in calcium-phosphorus system usually occurs due to the lack/deficiency of vitamin D, which is very common worldwide. Often a simple administration of vitamin D in optimal and individual dosages solves (prevents) the problem of hyperparathyroidism or reduces the aggressiveness of its course. Review of data from literary sources and results of own research on pathogenetic patterns and clinical course of parathyroid diseases was carried out, and it was determined that the lack/deficiency of vitamin D is the most common ground of development of hyperparathyroidism, which affects the formation of parathyroid hyperplasia or adenoma, and the process itself is of a gradual, staged clinical development.