Soft-Tissue Calcification in Uremia

Abstract

The association between soft-tissue calcification (STC) and uremia has been recognized for more than 100 years,¹but it is only since the widespread use of regular dialysis and transplantation that this has become an important problem.² Virchow¹surmised that calcium salts dissolved from bone were carried in the blood and deposited at some distant site to form "calcium metastases," a process analogous to the dissemination of cells from a primary neoplasm. In a review of 88 patients,^"the underlying cause of metastatic calcification was nonmetabolic bone disease in 35, uremia in 23, primary hyperparathyroidism in 21, and vitamin D intoxication in 9. The lesions typically occur in the kidneys, stomach, lungs, and the left side of the heart, supposedly because of relative local alkalinity.⁴The essential feature of metastatic calcification is its occurrence in previously normal tissue exposed to an abnormal chemical environment, in contrast to dystrophic calcification which occurs in