A 15-year-old boy had hypercalcemia and renal insufficiency secondary to immobilization for multiple fractures. After being immobilized for 12 weeks he was noted to have hypercalcemia, a metabolic alkalosis, and renal insufficiency. Renal function studies demonstrated reduction in iothalamate sodium I125 clearance, increase in fractional excretion of sodium and phosphorus, and increased urinary excretion of calcium and magnesium. Except for increase in urinary magnesium excretion, results of repeat renal function studies were normal nine months later.
Immobilization hypercalcemia with renal insufficiency in adolescence appears to be related to the high rate of bone turnover. Reduction in renal function may be related to direct effect of excess calcium on the kidney. Other metabolic abnormalities may be related to decreased renal function or to effects of bone dissolution.
Possible therapeutic regimens include furosemide, corticosteroids, phosphate salts, and mithramycin.