CALCIUM-METABOLISM AND HYPERPARATHYROIDISM AFTER RENAL-TRANSPLANTATION

  • 1 January 1983
    • journal article
    • research article
    • Vol. 52  (205) , 67-78
Abstract
Plasma Ca and albumin levels were measured serially in 100 patients for 2-yr following successful renal transplantation. Mean plasma Ca increased during the first 6 mo. after grafting, in large part attributable to an increase in plasma albumin. The variance around the mean plasma Ca did not increase suggesting that mechanisms responsible for hypercalcemia were common to the majority of patients. Thirty-six percent of patients developed hypercalcemia within 2 yr of grafting but the incidence fell to 11% when more rigorous criteria for hypercalcemia were used. The mechanisms maintaining plasma Ca were studied in 29 of the patients, 9 of whom were hypercalcemic and 20 of whom were normocalcemic. Before transplantation, mean plasma Ca and phosphate levels were higher, the prevalence of subperiosteal erosions and extraskeletal calcification radiographically was greater, and the duration of hemodialysis treatment was longer in the hypercalcemic patients than in the normocalcemic recipients. At assessment after transplantation, hypercalcemic patients had lower levels of plasma phosphate, higher plasma levels of alkaline phosphatase and parathyroid hormone and higher hydroxyproline excretion. Renal function and 47Ca absorption were similar in the 2 groups. The major cause for apparent hypercalcemia in transplanted patients appeared to be an increase in plasma albumin. In patients with true hypercalcemia the major cause was pre-existing hyperparathyroidism where hypercalcemia was mediated by increased renal tubular reabsorption of Ca.