An Unusual Case of Bilateral Ureteric Obstruction Caused by Colorectal Cancer

Acute kidney injury (AKI) is a common complication in patients with cancer. The aetiology of these cases can be categorized into pre-renal, intra-renal, and post-renal causes based on the location of the lesion. Post-renal AKI is caused by obstructive uropathy, especially in malignancies of the bladder, prostate, uterus, and cervix, but less commonly in colorectal cancer. This can eventually lead to hyperkalaemia, metabolic acidosis, and acute renal failure. To emphasize that colorectal carcinoma is an uncommon cause of bilateral obstructive uropathy, we present this case of post-renal acute kidney injury to draw attention to and familiarize clinicians with its uncommon presentation. An 81-year-old male patient with a past medical history of recurrent colorectal cancer presented with fatigue and low urine output for two days in the emergency department. His examination was unremarkable. His blood gas analysis showed metabolic acidosis, hyperkalaemia, and AKI (warning stage 3). A computed tomography (CT) scan showed new bilateral renal pelvicalyceal dilatation and ureteric obstruction. He was admitted to the intensive treatment unit (ITU) with a diagnosis of AKI secondary to bilateral ureteric obstruction due to relapse of his colorectal cancer. Bilateral nephrostomies were performed, and his blood parameters improved gradually, along with returning urine output.