Magnesium deficit after renal transplantation with secondary posttransplantation hypocalcemia and hypophosphatemia.

Hypomagnesemia, hypocalcemia and hypophosphatemia after renal transplantation in an 18-year-old patient is described. Serum magnesium decreased in consequence of increased renal transplant function with high urinary magnesium excretion. At the time of serum magnesium depletion, pretransplantation hypocalcemia persisted and severe hypophosphatemia developed. Magnesium oxide treatment was followed by the increment not only in serum magnesium but also in serum calcium and phosphate to normal level. Causal relationship between magnesium deficit and impaired renal transplant tubular reabsorption of magnesium and between magnesium deficit and serum calcium and phosphate depletion in the patient is suggested.