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Kidney Week

Abstract: TH-PO111

Normal Renal Function in a Patient With Elevated Serum Creatinine

Session Information

  • AKI: Mechanisms - I
    November 03, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Muuse, Janelle, Christ Hospital, Cincinnati, Ohio, United States
  • Pennekamp, Alexander, Christ Hospital, Cincinnati, Ohio, United States
  • Hergenrother, John, Christ Hospital, Cincinnati, Ohio, United States
Introduction

Creatinine is an imperfect marker to estimate GFR, and awareness of situations where it will not accurately reflect kidney function is crucial. Creatinine is affected not only by states that increase or decrease its production (i.e. rhabdomyolysis, sarcopenia) but also by factors that affect its reabsorption in the tubule (or within the body).

Case Description

A 65 year old male with a history significant for prostate cancer was admitted to the hospital for abdominal pain and distention four days after undergoing a radical prostatectomy. Initial pertinent labs included a serum creatinine of 1.5mg/dL (baseline 1.0 mg/dL) and an eGFR of 47 (CKD-EPI 2009). He had a JP drain in place with large amounts of serosanguinous fluid. Imaging revealed postoperative ileus. On subsequent days, his creatinine continued to rise and was refractory to intravenous fluids. The patient became increasingly distended to the extent that abdominal compartment syndrome was a concern. A decompressing colonoscopy failed to relieve the patient’s symptoms. Lasix and albumin were given and caused his JP drain output to increase significantly.
The abdominal fluid was found to have a creatinine of 9.7, signifying a possible urine leak. By day 3, his serum creatinine rose to 4.10. Urinalysis was bland. A cystogram was then performed and demonstrated a moderate vesicourethral anastomotic leak. Due to the patient’s large urine output and lack of othermarkers of renal dysfunction such as fluid overload and electrolyte abnormalities, it was determined that both his ileus and elevated creatinine were caused by uroperitoneum. This was later confirmed by a cystatin c level. His urine leak was treated conservatively and his serum creatinine returned to normal in the following days.

Discussion

This was an unusual case of uroperitoneum post prostatectomy, as urine leaks most commonly present in the retroperitoneum. Creatinine absorbed into the peritoneum caused an elevated serum creatinine due to reabsorption of creatinine from the peritoneal space back into the blood. The utility of measuring cystatin c is highlighted here– his eGFR using cystatin c was found to be 52 (compared to 14 using the creatinine equation)– showing a much more accurate indicator of renal function. Identifying pseudo-acute renal failure was imperative in this case to avoid unnecessary interventions such as dialysis.