Emphysematous pyelonephritis in patients with diabetes mellitus.

Emphysematous pyelonephritis is a rare, life threatening complication of upper urinary tract infections, characterized by the presence of gas in renal parenchyma and perirenal space. It occurs in 90% of cases in diabetic patients and E coli is the most common causative germ The pathogenesis probably involves several factors including enhanced proliferation of microorganisms due to altered immune defences, mixed acid fermentation of glucose leading to gas production, and decreased elimination of the gas because of impaired tissue perfusion. Diagnosis is often delayed because the symptoms may be non-specific, as illustrated by the two cases we report herein. In patients with diabetes and febrile urinary tract infection, obstruction of the urinary tract should first be eliminated by echography. Then, if the infection does not rapidly respond to antimicrobial therapy, a scan should be performed. Aggressive management including correction of hemodynamics, parenteral antimicrobial therapy and diabetes control with insulin therapy is mandatory, but a surgical procedure (nephrectomy or drainage) is almost always required.