Endocrine Abstracts

Thyroid hormones have an important role in bone metabolism. In this case, hyperthyroidism causes secondary osteoporosis and osteopenia. There is very little information in the literature about the state of bone metabolism in children and adolescents with thyrotoxicosis. Thus, our work aimed to study the state of bone mineral density and levels of calciotropic hormones in children and adolescents with thyrotoxicosis. The study was conducted in a group of 19 children and adolescents with thyrotoxicosis at the age of 9–18 years. The control group consisted of 23 healthy children and adolescents. All studies were conducted in the RSSPMCE. Levels of TSH, fT4 and fT3, PTH and vitamin D were determined using a closed-type immunochemistry analyser Cobas e 411 Hitachi company HoffmanLeRoche (Switzerland) and its reagents. Bone mineral density was evaluated by dual-energy absorptiometry on a Stratos X-ray densitometer from DMS, France. The results of the study showed that the average value of the level of vitamin D in the control group was 20.4 ± 6.2 ng/ml, in the group with thyrotoxicosis – 12.3 ± 1.1 ng/ml, P <0.05. At the same time, vitamin D deficiency was detected in 43.4% of children and adolescents without endocrine pathology. In the group with thyrotoxicosis, vitamin D deficiency was diagnosed in 84.2%, and its deficiency in 15.8% of pediatric patients. The average level of parathyroid hormone in the control group was 49.2 ± 2.3 ng/ml, whereas, in the group with thyrotoxicosis, the average level of parathyroid hormone was significantly lower and amounted to 45.1 ± 3.9 ng/ml, P < 0.05. In the group with thyrotoxicosis, hypoparathyroidism occurred 4.9 times more often than among healthy children, 21.1% showed an increase in PTH levels of more than 65 ng/ml. According to the results of dual-energy X-ray absorptiometry in children and adolescents with thyrotoxicosis, the mean valuesand median of the Z-index of femoral neck, lumbar vertebrae and the total body were significantly lower than in the control group. In this control group, 4.2% of adolescents were diagnosed with juvenile osteoporosis. At the same time, in the group with thyrotoxicosis, 36.8% registered osteoporosis, P ≤ 0.01.Thyrotoxicosis in children and adolescents causes a decrease in BMD and increases the development of osteoporosis by almost nine times. Thus, thyrotoxicosis in children and adolescents causes a decrease in bone mineral density and is accompanied by hypoparathyroidism and vitamin D deficiency.