Renal emphysema in diabetic patients: CT evaluation.

Renal emphysema is a rare, fulminant, suppurative infection of pelvicaliceal system, renal parenchyma, perinephric tissues, and retroperitoneum. It is characterized by formation of gas. Invariably this condition is associated with diabetes mellitus and carries high mortality (40-90%). Renal emphysema can be classified into two distinct clinical entities: emphysematous pyelitis and emphysematous pyelonephritis. This classification has important prognostic and therapeutic implications. Herein we describe the computed tomographic findings in five unilateral cases of renal emphysema (two cases of emphysematous pyelitis and three cases of emphysematous pyelonephritis) in five insulin-dependent diabetic patients.