In order to elucidate the mechanism of derangement of calcium metabolism in patients under corticosteroid therapy, serum calcium, inorganic phosphorus, creatinine, alkaline phosphatase and parathyroid hormone (PTH) and urinary calcium, phosphorus and creatinine were measured and tubular reabsorption of phosphorus (%TRP) calculated in 20 patients before and during corticosteroid therapy up to 6 months. Serum calcium was significantly lower and serum PTH significantly higher in patients under corticosteroid therapy than those without it. During the course of corticosteroid treatment, serum calcium was significantly below the control level after 2 months of treatment, while urinary phosphorus excretion rose and %TRP fell significantlp after 6 months. These data would indicate a tendency of corticosteroid-induced hypocalcemia and secondary hyperparathyroidism with hyperphosphaturia in patients under corticosteroid therapy.
View full abstract