Renal tubular function in urinary stone disease

Abstract

There is much evidence that renal tubular function is more or less defective in nephrolithiasis. In order to make clear whether tubular dysfunction is a cause or consequence of stone disease, we conducted renal tubular function tests in 9 idiopathic calcium stone patients when the stone seemed to be no longer obstructive to the urinary tract on intravenous pyelographs. All the tests were repeated one month after removal of stones. We compared the values of tubular reabsorption of phosphate, urinary acidification ability and fractional excretion of magnesium, potassium and insulin before and after removal of stones, and found no significant difference. The urinary excretion of gamma-GT was elevated in some cases with calculi. However, after removal of them, it returned to a normal level. We concluded that if tubulopathy is consequent upon the stone disease, it may be caused by obstruction of the involved urinary tract with calculi.