An Overlooked Cause of Pseudo-Kidney Failure Due to Spontaneous Bladder Rupture 8 Years after Radiation Therapy

Introduction: Pseudo-renal failure is characterized by acute renal failure-like abnormalities despite normal renal function. The most common cause is bladder rupture. Pseudo-renal failure occurs secondary to reverse peritoneal dialysis. The initial diagnosis rate of bladder rupture is low; it is often misdiagnosed as peritonitis or acute renal failure. We report a case of pseudo-renal failure due to spontaneous bladder rupture and discuss its diagnostic challenges. Case Description: A 55-year-old woman underwent total hysterectomy and chemoradiotherapy for cervical cancer 8 years previously. She visited her family hospital because of abdominal pain and diarrhea, and ascitic effusion and elevated serum creatinine (S-Cr) were found. Fluid therapy was given for dehydration due to diarrhea, and antibiotic therapy was given for peritonitis due to enteritis. However, she was admitted to our hospital because of her high S-Cr level (9.7 mg/dL) and increased ascites. She had oliguria and uremic symptoms, and we performed diagnostics while initiating hemodialysis. We suspected urinary ascites because the serum cystatin C level (1.2 mg/dL) was inconsistent with the S-Cr level, and both the urea nitrogen (125.8 mg/dL) and creatinine (27.5 mg/dL) levels in the ascites were extremely high. Cystography showed leakage of contrast medium into the abdominal cavity (Figure), indicating pseudo-renal failure due to spontaneous bladder rupture. The S-Cr level normalized 2 days after urethral catheter insertion, and the ascites disappeared. Discussion: The incidence of spontaneous bladder rupture is approximately 0.002%, and pelvic radiation and alcohol intoxication are the most common causes. The initial misdiagnosis rate is 64% because of the nonspecific symptoms, and delayed diagnosis is common. Cystography is useful for definitive diagnosis. In this case, the increased ratios of S-Cr to cystatin C and ascites creatinine to S-Cr assisted the diagnosis, as reported in previous studies. The differential diagnosis of pseudo-renal failure is important when acute renal failure with ascites effusion occurs after pelvic radiation.