Abstract: TH-PO1088
Cystatin C for Differentiating True AKI from Pseudo-AKI Due to Intraperitoneal Urinary Leak: A Case Report and Literature Review
Session Information
- Pathology and Lab Medicine
October 22, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pathology and Lab Medicine
- 1700 Pathology and Lab Medicine
Authors
- Lowe, Derek, William Beaumont Army Medical Center, Fort Bliss, Texas, United States
- Nguyen, Julia, Walter Reed National Military Medical Center, Bethesda, Maryland, United States
- Nguyen, Phong T., William Beaumont Army Medical Center, Fort Bliss, Texas, United States
- Yuan, Christina M., Uniformed Services University of the Health Sciences, Bethesda, Maryland, United States
- Forster, Benjamin Michael, William Beaumont Army Medical Center, Fort Bliss, Texas, United States
- Nee, Robert, Walter Reed National Military Medical Center, Bethesda, Maryland, United States
Background
Urinary ascites (intraperitoneal urine accumulation due to lower urinary tract disruption) is an uncommon cause of pseudo-acute kidney injury (AKI). Urine solutes are resorbed across the peritoneum, causing serum creatinine (sCr) to increase. Serum cystatin C (sCysC), which is not excreted in urine, may be used to estimate renal function in this situation. We present a case of postoperative urinary ascites, review eight similar cases, and evaluate sCysC utility in identifying pseudo-AKI.
Methods
Literature search found 8 case reports describing urinary ascites with concurrent sCysC measurement. Data on clinical presentation, urine leak cause, laboratory results, interventions, and outcomes were extracted on these 8 cases in addition to the index case.
Results
Urinary leak was due to trauma/surgical injury (n=5) or spontaneous bladder rupture (n=4). sCr was markedly elevated in all cases, while sCysC was normal or mildly elevated, suggesting preserved intrinsic renal function. Diagnostic imaging and ascites fluid analysis confirmed urinary ascites (ascites Cr similar to urine Cr). After intervention, sCr quickly normalized. Two underwent dialysis before the diagnosis was recognized. No patient developed intrinsic AKI after leak correction.
Conclusion
Normal sCysC with elevated sCr strongly suggested pseudo-AKI due to urinary ascites. Several had sCr to sCysC ratios far above normal. Ascites Cr to sCr ratio >1:1 was uniformly present. Delayed diagnosis risks unnecessary dialysis. Timely correction completely reverses AKI.
Urinary ascites is an uncommon cause of reversible AKI. Normal/near-normal sCysC with markedly elevated sCr should prompt evaluation for urinary leak, especially in postoperative or trauma-related AKI and ascites.