Obstructive Nephropathy Without Hydronephrosis: Suspicion Is the Key.

Urinary tract obstruction leading to acute kidney injury is usually associated with bilateral hydroureters and hydronephrosis, often accompanied by oliguria. We present an atypical case of obstructive uropathy without these features that presented with severe acute kidney injury. A 64-year-old male with no known medical history has presented with a 2-week history of nausea, decreased appetite, flank pain, and lower extremity edema, and was found to have an elevated creatinine of 10.5 mg/dL. Renal ultrasound showed mild prominence of the bilateral renal collecting systems with no evidence of hydronephrosis. Computed tomography scan showed findings suggestive of retroperitoneal fibrosis involving ureteral region and bilateral ureteral stent placement has led to dramatic improvement of creatinine to 1.3 mg/dL over the next 4 days.