Primary Hyperparathyroidism, Hypoparathyroidism and Vitamin D

The use of active vitamin D analogues in hypoparathyroidism is well established, since low levels of parathyroid hormone (PTH) reduce the activity of renal 1 alpha-hydroxylase, reducing the synthesis of 1,25-OH-vitamin D and consequently decreasing serum calcium and magnesium and increasing phosphatemia. In primary hyperparathyroidism, vitamin D deficit additionally contributes to the elevation of PTH and serum calcium and to the reduction of phosphatemia. In addition, it increases the risk of hungry bone syndrome postoperatively. Vitamin D supplementation in primary hyperparathyroidism is safe if hypercalcemia is mild (<12 mg/dL) and if calcium levels are periodically monitored, and is associated with reduced bone remodelling, the risk of hungry bone syndrome and lower postoperative PTH levels. A minimum 25OH-vitamine D of 20 ng/mL is advised in these patients.