Endocrine Abstracts

Aim: The aim of this prospective study is to assess if there is any correlation between parathyroid hyperplasia detected by ultrasound and variables connected with secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD) stage 5, treated by dialysis and to determine the PTH level, above which the hyperplasia of parathyroid glands could be visualized.

Methods: Thirty-one patients (14 men and 17 women) with CKD stage 5, treated by haemodialysis for more than 6 months in The University Hospital ‘St. Marina’ in Varna, Bulgaria participated in the study. There are divided in two groups according to the presence of parathyroid hyperplasia visible by high- resolution ultrasound: group 1- patients without parathyroid hyperplasia and group 2- patients with visible hyperplasia. We analysed variables such as duration of dialysis and CKD, levels of parathyroid hormone (PTH), calcium, phosphorus, calcium x phosphorus, alkaline phosphatase. In group 2 we also assessed the number of enlarged parathyroid glands, their total volume, the volume of the most enlarged parathyroid gland and the cut-off value for PTH above which the hyperplasia is visualized by ultrasound.

Results: Using a high-resolution ultrasound we detected parathyroid hyperplasia in 24 patients (77.4%). In group 2 the average PTH level is significantly higher compared to group 1 (P 0.00) with higher levels of phosphorus, calcium x phosphorus, alkaline phosphatase, duration of the CKD and time on dialysis therapy. Significant difference in alkaline phosphatase levels between the two groups is also observed (P 0.004). There is moderate significant correlation between the total volume of enlarged parathyroid glands and levels of phosphorus (r 0,443) and calcium x phosphorus (r 0.466). According to our results the level of PTH above which the hyperplasia becomes visible is 617.5 pg/ml.

Conclusions: SHPT is a relatively common abnormality seen among patients suffering from chronic kidney disease. Its early detection is very important for starting an appropriate therapy, preventing bone and cardiovascular complications.

Keywords: secondary hyperparathyroidism, chronic kidney disease, hyperplasia, ultrasound, parathyroid hormone