[Anomalies of phosphate and calcium metabolism in chronic renal insufficiency]

The disturbances of calcium and phosphate metabolism in chronic renal failure involve mainly two hormones, namely calcitriol and parathyroid hormone. They are thought to start with a reduction in calcitriol synthesis, probably due to several mechanisms, and with a reduced action of calcitriol at its target tissues, including the parathyroid cell. They may lead to several complications of clinical importance including both secondary hyperparathyroidism, in the presence or absence of vitamin D deficiency, and hypoparathyroidism. The corresponding expression at the bone level may be osteitis fibrosa, osteomalacia or adynamic bone disease. These complications are frequently associated with soft tissue calcifications, mainly vascular and periarticular, with serious clinical consequences in some patients.