Evolution of secondary hyperparathyroidism after renal transplantation

Parathormone levels were determined in 17 patients with functioning renal transplants. In 8 patients recently transplanted, very high serum levels of parathormone were found without obvious relation to the glomerular filtration rate. Hypophosphatemia was also present in these cases. In 9 other patients studied 2-7 years after transplantation the mean level of parathormone was lower than in the previous group but levels above normal were noted in half of the patients, some of which had perfect renal function and normal serum phosphorus. The response to induced hypercalcemia was used as a sensitive test to reveal abnormal responses even in cases which initially had normal peripheral levels of parathormone. From these results, tertiary hyperparathyroidism would appear to be rare although hyperfunctioning parathyroid glands can be demonstrated long after kidney transplantation, even when renal function is close to normal.