Hypercalcemia following high dose Vitamin D therapy in end stage renal failure

Background. Secondary hyperparathyroidism in chronic renal failure is due to the lack of calcitriol. Therapy with vitamin D prevents renal osteopathy. However, the dosage and monitoring of vitamin D therapy requires profound knowledge of calcium-phosphate metabolism in chronic renal failure. Case report. We present two patients in end stage renal failure with substantial hypercalcemia and hyperphosphatemia following high dose vitamin D therapy. Parathormone was suppressed in both cases. One patient showed cardiac calcifications leading to third degree heart block. In both cases a temporary discontinuation of vitamin D therapy, dietetic instructions, phosphate binders and adequate renal replacement therapy led to a normalized calcium-phosphate metabolism. Discussion. The administration of vitamin D represents a standard therapy in chronic renal failure. However, this case demonstrates the consequences of inadequate monitoring of vitamin D therapy. To determine the appropriate dose we recommend careful monitoring of serum calcium, phosphate, parathormone and alkaline phosphatase in a paediatric nephrology department.