Julia R. Fielding, M.D. Brigham and Women's Hospital, Harvard Medical School Boston, Massachusetts

45 Year-old Woman with Flank Pain

This middle-aged, black, insulin-dependent, diabetic woman presented to the ER with flank pain. Urinalysis demonstrated findings suggestive of infection and she had a mild fever, A supine view of the abdomen (Figure 1) and a CT scan (Figure 2) were obtained. What is the diagnosis and what are the treatment options?

Answer: Emphysematous pyelonephritis. This type of life-threatening infection occurs almost solely in diabetics. The most common organism isolated from the urine is E. coli, although other gas forming organisms have been reported. Diagnosis can be made on the plain film alone which demonstrates a large UPJ stone and perinephric gas. The CT exam shows a large perinephric abcess as well as some intraparenchymal gas. In the vast majority of cases, urgent nephrectomy is performed. The advent of new antibiotics and ICU care has decreased the peri-operative mortality to approximately 20%. In this case, a combination of percutaneous drainage of the perinephric abcess and percutaneous nephrostomy to relieve the obstruction was performed. After a difficult hospital course, the patient returned home, kidney intact.

Reference:

Wan Y, Lee T, Bullard MJ, Tsai C. Acute gas-producing bacterial renal infection: Correlation between imaging findings and clinical outcome. Radiology 1996; 198:433-438.