A rare case of emphysematous pyelonephritis within a horseshoe kidney

To correlate imaging findings of types I and II emphysematous pyelonephritis (EPN) with clinical course and prognosis. The imaging studies and clinical outcome in 38 patients with EPN were retrospectively studied. The imaging studies performed included radiography (n = 33), computed tomography (n = 31), and ultrasonography (n = 35). Two types of EPN were identified. Type I EPN was characterized by parenchymal destruction with either absence of fluid collection or presence of streaky or mottled gas. Type II EPN was characterized as either renal or perirenal fluid collections with bubbly or loculated gas or gas in the collecting system. The mortality rate for type I EPN (69%) was higher than that for type II (18%). Type I EPN tended to have a more fulminant course with a significantly shorter interval from clinical onset to death (P < .001). Two distinct types of EPN can be seen radiologically, and the differentiation is important due to the prognostic difference.

Diabetes mellitus is a common multisystemic disease with serious effects on the genitourinary system. In the radiology literature, little attention has been paid to developing an integral approach to imaging of the genitourinary tract in diabetes. The long-term effects of diabetes on the genitourinary system include diabetic nephropathy, papillary necrosis, renal artery stenosis, diabetic cystopathy, and vas deferens calcification. Diabetes-associated urinary tract infections include renal and perirenal abscesses, gas-forming infections such as emphysematous pyelonephritis and emphysematous cystitis, fungal infections, and xanthogranulomatous pyelonephritis. Diabetes-associated genital infections include Fournier gangrene and postmenopausal tubo-ovarian abscess. In a diabetic with fever of unknown origin or in the event of a persistent infection in a diabetic with clinical deterioration despite use of antibiotics, radiologic studies can demonstrate the presence of genitourinary complications. Finally, radiologists should be aware of the risk of contrast material-induced nephropathy in diabetics.

Emphysematous pyelonephritis is an acute bacterial infection responsible for a high mortality. It is characterized by bacterial gas production in the renal parenchyma, occurring in diabetic patients in most case. The gold standard treatment has always been surgery associated with antibiotic therapy. We report the case of a 58 year-old woman, with undocumented diabetes, who presented with emphysematous pyelonephritis complicated with septic shock and acute renal failure. Antibiotherapy alone was successful.