Gas-containing renal stones.

Emphysematous pyelonephritis is a rare, but potentially lethal, possible sequela of nephrolithiasis, occurring most commonly in diabetic patients. The diagnosis of emphysematous pyelonephritis relies on the radiologic finding of gas in the renal parenchyma. We present the case of a patient with sarcoidosis, diabetes, and obstructing, gas-containing ureteral stones. Gas-containing renal stones are exceedingly rare, but have been linked to serious renal infections. The case management and a brief review of the published reports follow. We propose that gas-containing stones be considered evidence of emphysematous pyelonephritis in certain clinical settings.