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Kidney Week

Abstract: PUB022

An Unusual Case of Retroperitoneal Fibrosis Masking Severe Hydronephrosis

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

  • Kalfayan, Garo, Los Robles Regional Medical Center, Thousand Oaks, California, United States
  • Gower, Arian, Los Robles Regional Medical Center, Thousand Oaks, California, United States
  • Takher, Jasprit, Los Robles Regional Medical Center, Thousand Oaks, California, United States
Introduction

Acute kidney injury (AKI) increases morbidity and mortality. Hydronephrosis is dilatation and distension of the renal collecting system of one or both kidneys due to obstruction of urine outflow distal to the renal pelvis. This a unique case as the degree of hydronephrosis is being undervalued due to the retroperitoneal fibrosis.

Case Description

A 75 year old female presented with progressively worsening abdominal pain. Initial laboratory evaluation demonstrated blood urea nitrogen (BUN) of 19 mg/dL and creatinine of 1.09 mg/dL. Lab values approximately 2 years prior were 10 mg/dl and 0.60 mg/dl. Computed Tomography showed extensive inflammatory changes in the lower pelvis, centered mostly around the cervix and extending into bilateral lower retroperitoneum. Ultrasound demonstrated very mild bilateral hydronephrosis. Nuclear medicine renal with Lasix showed significant renal impairment with an element of renal obstruction that cannot be excluded. Creatinine worsened to 6.46 mg/dl and BUN 48 mg/dL. It was hypothesized that imaging was incorrectly portraying the degree of hydronephrosis, and potentially it may be worse than a mild degree. Right sided percutaneous nephrostomy tube was placed with 2,175 mL output in 24 hour period. Creatinine improved to 3.76 mg/dL and BUN 46 mg/dL. Ultrasound six days later confirmed resolution of hydronephrosis, and return of creatinine to 0.48 mg/dL and BUN to 14 mg/dL.

Discussion

The resolution of hydronephrosis and AKI after percutaneous nephrostomy tube placement with significant output confirmed the hypothesis that imaging was potentially inaccurately portraying the degree of hydronephrosis. This can help guide future treatment when considering whether retroperitoneal fibrosis may be masking the degree of hydronephrosis.

Retroperitoneal fibrosis appreciated on Coronal CT Abdomen (red arrow)