Hypercalcemia following renal transplantation: causes and consequences
Conceicao, S.C.; Wilkinson, R.; Feest, T.G.; Owen, J.P.; Dewar, J.; Kerr, D.N.
Clinical Nephrology 16(5): 235-244
1981
ISSN/ISBN: 0301-0430 PMID: 7030546 Document Number: 168659
In an attempt to define the incidence of, and the factors responsible for, postransplant hypercalcemia, 95 transplant were studied who had functioning grafts for between 6 mo. and 12 yr. Serum ionized and total Ca immunologically active parthyroid hormone (iPTH), phosphate, and other biochemical variables, and recorded the clinical state of the patients, duration of maintenance hemodialysis prior to transplantation, and where available bone biopsy findings at the time of the transplant. In 36 patients skeletal radiological studies were performed. Serum ionized Ca concentration was raised in 47 patients, but serum total Ca was above normal in only 10, 2 of whom had normal ionized Ca concentrations. Hypophosphatemia was present in only 15 patients, 4 of whom were normocalcemic. Serum immunoreactive parathyroid hormone (iPTH) was raised in 33 patients, but was not related to the time since transplant or to serum Ca or P concentration. This does not exlude hyperparathyroidism as a cause of hypercalcemia, as renal function will markedly influence all these variables. The degree of osteitis fibrosa on bone biopsy at the time of transplantation was related to serum Ca concentration and inversely related to serum P concentration. Hyperparathyroidism may be an important factor in post-transplant hypercalcemia and hypophosphatemia. The clinical significance of hypercalcemia is uncertain. Normocalcemic and hypercalcemia. The clinical significance of hypercalcemia is uncertain. Normocalcemic and hypercalcemic patients were symptomatically the same, although hypercalcemic patients had an increased incidence of subperiosteal erosions and arterial calcification. No relationship was found between avascular necrosis and hypercalcemia or serum iPTH levels. Hypercalcemia may damage transplant function, but as renal failure itself reduces serum Ca concentration the effect of hypercalcemia on renal function cannot be determined without a prospective long-term study.