[Ectopic calcification in patients with aplastic bone disease undergoing dialysis]

Aplastic bone disease (adynamic bone disease) has been attracted attention as the most frequent type of renal osteodystrophy in patients undergoing dialysis, and relatively low serum parathyroid hormone level is considered to be the major cause of aplastic bone disease. In aplastic bone disease, both the number of osteoblast and osteoclast are few and the speed of bone turnover is low, therefore, buffering action of bone for calcium and phosphorus is extremely disturbed. Hypercalcemia due to a prescription of large dose calcium carbonate and hyperphosphatemia derived by high protein diet in this occasion induce high serum calcium and phosphorus product level, and ectopic calcification is likely to occur. When ectopic calcification occur at artery it might develop ischemic change of visceral organ. Recently, the strong association between coronary arterial calcification and high serum calcium and phosphorus products is clarified by a method of electron-beam computed tomography. Based on these findings, high calcium and phosphorus product is now believed as a risk for poor patients' survival. Thus, we should pay attention to calcium and phosphorus product in patients suffering from aplastic bone disease.