In which patients with nephrocalcinosis and an incomplete distal RTA would you consider further testing for medullary sponge kidney?  

Yes, definitely. The better question is how to test. Since sponge kidney is an anatomical disorder of dilated collecting ducts in the renal papillae, it's best to look anatomically. These are 3-dimensional structures and are best seen with a 3-dimensional image. We no longer have intravenous pyelogr...