Abstract: TH-PO0725
A Case of Pseudo-AKI Associated with a Sigmoidovesical Fistula
Session Information
- AKI: Prevention, Diagnostics, and Management
October 22, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 101 AKI: Epidemiology, Risk Factors, and Prevention
Authors
- Ota, Eriko, St Marianna University, Kawasaki, Japan
- Ogata, Masatomo, St Marianna University, Kawasaki, Japan
- Shibagaki, Yugo, St Marianna University, Kawasaki, Japan
Introduction
Pseudo–acute kidney injury (pseudo-AKI) refers to elevation of serum creatinine without true deterioration of kidney function. It may occur when urinary creatinine is reabsorbed through extrarenal pathways, such as in urinary ascites. However, pseudo-AKI associated with enterovesical fistula has rarely been reported. We report a case of pseudo-AKI associated with a sigmoidovesical fistula, in which discordance between serum creatinine and cystatin C levels provided an important diagnostic clue.
Case Description
A 66-year-old man was referred for evaluation of acute kidney injury (AKI). Four months earlier, he had developed diarrhea and painful urination and had been treated for a presumed urinary tract infection. However, his symptoms recurred. Abdominal ultrasonography revealed left hydronephrosis and irregular thickening of the posterior bladder wall. Non-contrast computed tomography (CT) demonstrated sigmoid colon penetration with abscess formation, suggesting an enterovesical fistula.
Cystography revealed a sigmoidovesical fistula. During hospitalization, while managed with an indwelling urinary catheter, he developed decreased urine output and watery diarrhea. His serum creatinine (Cr) level increased from 1.88 mg/dL to 2.37 mg/dL.
Because fecal material was observed within the urinary catheter, catheter obstruction was suspected. After replacement with a 16-Fr catheter and irrigation, approximately 2 L of urine was drained, followed by rapid improvement in serum Cr levels. In contrast, serum cystatin C levels remained stable at 2.08–2.09 mg/L throughout the clinical course.
Discussion
In this case, obstruction of the urinary catheter likely increased intravesical pressure, resulting in urinary flow into the intestinal tract through the sigmoidovesical fistula. Subsequent intestinal absorption of urinary creatinine was considered to have caused elevation of serum Cr, representing pseudo-AKI. An important finding was the discordance between serum creatinine and cystatin C levels. Despite elevation of serum Cr, cystatin C levels remained stable, suggesting preserved kidney function. Because cystatin C is less influenced by extrarenal creatinine handling, dissociation between serum Cr and cystatin C may help distinguish pseudo-AKI from true AKI.
This case suggests that elevated serum creatinine does not necessarily indicate true kidney dysfunction in patients with enterovesical fistula.
Acknowledgment
All authors contributed substantially to the conception, drafting, and revision of the manuscript and approved the final version for publication.