HistoryA 4-year-old sexually intact male Yorkshire Terrier was examined because of intermittent dysuria of approximately 1 month' s duration. Two days previously, the dog had a consistently poor urine stream. There was no evidence of blood in the urine; however, blood was observed in the feces. Stranguria had been observed 2 days previously. The result of a recent heartworm test was negative, and immunizations were current.Physical examination revealed a firm, moderately distended urinary bladder and bilateral grade II of IV medial patellar luxation. Bilaterally symmetric prostatomegaly was detected during per rectal examination. Results of a CBC were within reference ranges. A mildly high BUN concentration (32 mg/dL; reference range, 7.0 to 27.0 mg/dL) was identified on serum biochemical analysis. Urine was collected by cystocentesis. Urine specific gravity was 1.025. Urinalysis by use of a commercially available reagent test strip revealed proteinuria (1+) and blood (3+). Urine contained 11 to 20 WBCs/hpf and 21 to 50 RBCs/hpf. Urine was not submitted for bacteriologic culture. Radiographs of the abdomen were obtained (Figure 1).Determine whether additional imaging studies are required, or make your diagnosis from Figure 1-then turn the page →