Acute Urinary Retention Leading to Post-renal Acute Kidney Injury Post-radiotherapy: A Case Report.

A man in his 70s with high-risk localized prostate adenocarcinoma underwent definitive external beam radiotherapy (EBRT) to the prostate and pelvis with concurrent androgen deprivation therapy using leuprolide. Eight days after completion of radiotherapy, he developed acute urinary retention (AUR) with overflow incontinence, constipation, and post-renal acute kidney injury (AKI), requiring hospitalization and bladder decompression with Foley catheter placement. Initial urine output was approximately 1 liter, and creatinine improved from 4.89 mg/dL to 1.46 mg/dL after decompression. Imaging demonstrated mild left hydronephrosis and chronic renal disease without an obstructing calculus. He was discharged home on tamsulosin and a bowel regimen with a Foley catheter in place. Persistent catheter dependence subsequently required transurethral resection of the prostate (TURP) with improvement in symptoms. This case report describes a case of severe acute urinary retention with post-renal acute kidney injury occurring shortly after prostate and pelvic radiotherapy. The obstruction was likely multifactorial, with radiation-associated inflammation or edema potentially aggravating the underlying outlet issues and constipation. Prompt recognition and bladder decompression may permit rapid renal recovery and are important in patients with reduced renal reserves.