Imaging diagnosis of emphysematous pyelonephritis in a non-diabetic dog

An 11-year-old, 4.3 kg, mixed breed, intact female dog exhibiting vomiting and a reduced appetite was presented. On physical examination, palpation of the right kidney elicited discomfort. Blood analysis revealed leukocytosis with neutrophilia, and elevation of alkaline phosphatase and blood urea nitrogen. Escherichia coli was detected in urine culture, whereas urine analysis showed absence of glucose. Radiography and ultrasonography suggested that there was gas in the right renal parenchyma, and computed tomography was performed while the dog was awake to investigate the suspected gas in the right kidney. After unilateral ureteronephrectomy, a histological diagnosis of right emphysematous pyelonephritis (EPN) was made. EPN refers to a severe necrotizing infection of the renal parenchyma with gas accumulation in the tissue. It is rare in both human and veterinary medicine, and almost all EPN patients have uncontrolled diabetes mellitus. This case report describes the imaging-based diagnosis of a rare occurrence of unilateral EPN in a non-diabetic dog.