Talk to Urologist on BPH, Suprapubic Catheter For Last 2 Weeks. Blood In Urine Bag -2days

My father has had BPH, prostate weighing 80 gm,with voiding difficulties. He also has a urethral stricture .he was planned for a cystoscopy and turp. But due to large stricture, a supra pubic catheter was put in. The plan was to get a urethogram done. Since last 2 days, there is blood stained urine in the urine bag. What can be the reason, apart from infection. There's no fever