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Kidney Week

Abstract: SA-PO550

Absence of Hydronephrosis Does Not Exclude Obstructive Nephropathy

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical, Outcomes, and Trials

Authors

  • Koratala, Abhilash, University of Florida, Gainesville, Florida, United States
  • Olaoye, Olanrewaju Adebayo, University of Florida, Division of Nephrology, Gainesville, Florida, United States
Introduction

Clinicians should be aware of the pitfalls associated with diagnostic renal imaging.

Case Description

A 63-year-old man with a history of nephrolithiasis and neurogenic bladder requiring chronic indwelling urinary catheter was admitted for urinary tract infection and acute kidney injury (AKI) with a serum creatinine of 3.6 mg/dL (baseline ~1.9-2.2). Bedside renal sonogram did not demonstrate hydronephrosis or nephrolithiasis [Figure-1A,B]. Non-contrast CT scan of the abdomen also was negative for hydronephrosis but showed a 2.6 cm staghorn-appearing calculus in the right kidney [Figure-1C]. As the patient appeared dehydrated, he was treated with intravenous hydration along with antibiotics. However, renal function continued to worsen. Because of high index of suspicion for obstructive nephropathy, a radioisotope-lasix renogram was performed, which demonstrated complete obstruction on the right [Figure-2A]. Moreover, right kidney had a differential function of ~70%, which explains AKI with unilateral obstruction. Interestingly, a repeat renal sonogram demonstrated mild hydronephrosis and calculus in the right kidney [Figure-2B,C]. Serum creatinine improved significantly after nephrostomy tube placement, reaching baseline in a few days.

Discussion

Renal imaging can be negative for hydronephrosis in the setting of volume depletion. It should be repeated after volume repletion if the index of suspicion for obstructive nephropathy is high. Radioisotope renography is beneficial in selected cases. Early diagnosis is crucial for timely intervention and prevention of irreversible renal injury.