Medullary sponge kidney and urolithiasis.

A review of the urographic findings in 200 patients with renal colic due to urolithiasis demonstrated radiological evidence of medullary sponge kidney in 34, an incidence of 17%. In the majority, the diagnosis was readily made and the changes were bilateral and extensive. This relatively high incidence suggests that medullary sponge kidney may be a contributing factor in a population already predisposed to calculus formation because of other factors such as diet and dehydration.