Renal hypercalciuria and metabolic acidosis associated with medullary sponge kidney: effect of alkali therapy.

Sixteen patients with medullary sponge kidney (MSK) and renal stones underwent evaluation of calcium metabolism and acid base balance. Six normal subjects and eight patients with non-MSK absorptive hypercalciuria served as control. Nine (56%) were hypercalciuric and seven (44%) were normocalciuric (N-MSK). Hypercalciuria was divided into absorptive (AH-MSK, n = 2) and renal leak hyerpcalciuria (RH-MSK, n = 7). The mean of minimal urine pH of RH-MSK group (5.28 +/- 0.09 (SE] was significantly higher than that of normal control (4.78 +/- 0.12) and of non-MSK AH (4.80 +/- 0.6) during acute acid challenge. The mean of the arterial blood HCO3 concentration of RH-MSK group was significantly lower than that of two control groups. The urine calcium and a frequency of stone passage were decreased significantly after alkali treatment in RH-MSK.