Ion Dan Bucaloiu
Nephrology Program Director
Geisinger Medical Center, United States
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Title: Reflux Anuria: An Unusual Cause of Postoperative Acute Kidney Injury
Introduction: Reflux anuria is a rare and serious complication of bilateral prophylactic ureteral stenting (PUS). While the exact mechanism is not clearly understood, it is characterized by acute ureteral tract obstruction leading to acute kidney injury (AKI). We present a case of acute reflux anuria initially mistaken for prerenal kidney injury complicated by acute hypoxic respiratory failure secondary to fluid overload pulmonary edema requiring transfer to the intensive care unit (ICU).
Description: A 57-year-old female underwent surgical repair of a colovesical fistula. Preoperatively, PUS was performed to reduce the risk for iatrogenic ureteral injury. Immediately after surgery, the ureteral catheters were removed and a Foley catheter was left in place. 24 hours after surgery, decreased urine output was noted which did not improve with several boluses of IV crystalloid. The following day, her creatinine had risen to 2.3 mg/dL from a preoperative baseline of 0.9 mg/dL. A fractional excretion of sodium was calculated at 0.5% and interpreted as suggestive of a pre-renal etiology of the AKI. Additional fluid boluses were administered resulting in respiratory failure due to acute pulmonary edema. She was emergently intubated and transferred to the ICU. A renal ultrasound showed mild bilateral hydronephrosis. Nephrology was consulted for emergent hemodialysis. Due to the high suspicion for reflux anuria, the patient underwent emergent retrograde pyelogram showing complete absence of ureteral efflux bilaterally. Bilateral ureteral stenting resulted in immediate restoration of urine output with gradual resolution of the AKI and pulmonary edema with no requirement for hemodialysis.
Discussion: A high index of suspicion for reflux anuria as a potential complication of PUS is important for appropriate management and avoidance of additional patient morbidity. Traditional tests used in evaluation of AKI may be deceiving as ureteral obstruction may be associated with excess sodium conservation in the acute phase. Early renal imaging findings of obstruction are often subtle or absent. The appropriate management is prompt management of the ureteral obstruction.