The Case | Azotemia without renal failure

A 75-year-old male was transferred to our facility from an outside hospital for the management of complications of acute pancreatitis. There he was diagnosed with a common bile duct stone and underwent endoscopic retrograde cholangiopancreatography 6 weeks before transfer. His course was complicated by acute pancreatitis with a pseudocyst compressing the right ureter requiring ureteral stenting and by Clostridium difficile infection. All nutrition and hydration was given by tube feeds via a gastrojejunostomy tube, including 3?g/kg/day of protein in an attempt to reverse his 14?kg weight loss. At the time of transfer, laboratory abnormalities included blood urea nitrogen (BUN) concentration of 96?mg/dl, creatinine (Cr) of 0.88?mg/dl, albumin 2.8?g/dl, alkaline phosphatase of 238?U/l, and lipase 197?U/l. Other electrolytes were normal. At the time of admission to the outside hospital his BUN was 16?mg/dl, and Cr was 0.8?mg/dl. Three days before transfer his BUN was 77?mg/dl. The patient reported that his urine output was significantly reduced such that he was voiding very small amounts once or twice per day. Computed tomography at our facility showed pneumobilia and gas in the right renal collecting system (Figure 1), not seen on imaging 2 weeks prior. When asked directly, the patient admitted to pneumaturia.