The stone-forming kidney: a study of functional differences between individual kidneys in idiopathic renal lithiasis

The 24-hour urinary excretion of various electrolytes, as well as the glomerular filtration rate, renal plasma flow and maximal rate of tubular excretion of para-aminohippuric acid was measured in each kidney of 10 patients with idiopathic renal lithiasis. Results in hypercalciuric patients indicate that, in contrast to earlier views, actively stone-forming, normally functioning kidneys are normocalciuric but hypophosphaturic in comparison to their mates with inactive or no stone disease, which are hypercalciuric but normophosphaturic. Therefore, hypophosphaturia rather than hypercalciuria may be an important calculogenic factor in some patients.