Pseudo-Renal Failure in the Context of Traumatic Bladder Rupture

Abstract

The bladder is both an intraperitoneal and extraperitoneal structure. Its anatomical position increases its risk of rupture. The resultant urine leak or extravasation can be intraperitoneal, extraperitoneal, or even both-with the former leading to more sinister outcomes. Intraperitoneal bladder rupture can lead to urinary ascites which along with anuria and abdominal pain, can present with an apparent abrupt decline in renal function as the creatinine-rich products diffuse across the peritoneal membrane. Glomerular filtration rate, a measure of kidney function is related to the levels of serum creatinine. Clinicians can therefore misdiagnose their patient with acute kidney injury when the serum creatinine is elevated as a consequence of urine being present in the peritoneal space. This is a case report of a 62-year-old male with pseudo-renal failure following intraperitoneal bladder rupture after a fall face-forwards three hours previously. The fall was due to icy conditions outside and no preceding symptoms were reported. He presented to the Accident and Emergency department with abdominal pain and no other positive symptoms. The patient had a good World Health Organisation (WHO) performance status with a background of hypertension, diabetes, and hypercholesterolemia. The bedside examination of the patient revealed a distended, abdomen with peritonitis. There were no signs of urogenital trauma. Blood testing revealed a low estimated glomerular filtration rate (eGFR) and raised creatinine (eGFR of 7 millilitres/minute and creatinine of 658 micromoles/litre). Computerised tomography examination of the abdomen and pelvis (CTAP) revealed free fluid within the peritoneal cavity and an irregular bladder wall. A CT cystogram and consultation with urology led to the diagnosis of intraperitoneal bladder rupture. The patient’s renal function from an initial set of blood tests was reduced. This was not a true impairment in renal function but rather a complication secondary to extravasation of urine in the intraperitoneal space, ie., pseudo renal failure. This supposed impairment in renal function had numerous implications. It affected the choice of antibiotics; amoxicillin and gentamicin were given at a reduced dose due to the patient’s renal function and the patient was prepared for operation theatre. The patient's blood creatinine was falsely elevated at 658 micromoles/litre due to the diffusion of creatinine from the free urine in the peritoneal space into the blood. This painted a false image of renal failure and protracted the clinical decision-making process. Relatively simple measures like an ascitic tap could have helped to differentiate this from a true acute kidney injury and could have resulted in quicker and more effective treatment of this patient. The patient went on to have bladder repair under urology. His follow-up cystogram four weeks post-operation did not show any leak.