BPH - benign prostatic hyperplasia

70 year old man presented to his GP after feeling unwell for 2 weeks. He also gave a history of frequent micturition in the last 1 year. Blood test showed a grossly elevated creatinine.
Ultrasound showed an enlarged prostate gland measuring 80cc in volume (normal <30cc).
This is consistent with BPH

Scans of his kidneys showed bilateral small kidneys with thin parenchyma.
Right kidney measures 10.1cm in bipolar length and 8mm parenchymal thickness.
Left kidney measures 9.7cm in bipolar length and 7mm parenchymal thickness.