This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': '60 yrs old male with poor stream of urine, post void residual urine is 400m1, b/1 hydronephrosis and prostate weighing 70 g. His urea is 120 and creat 3.5. Ideal "next immediate" step : \nSelect and explain. \nA. Catheterize with Foley catheter, B. b/1 PC Nephrostomies, C. CT to rule out ca, D. MRI pelvis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans is \'a\' i.e. Catheterize with Foley catheter "Catheterization is mandatory for acute urinary retention. Spontaneous voiding may return, but a catheter should be left indwelling for 3 days while detruson tone returns."- CSDT I3/e This is a case of bladder outlet obstruction most likely due to BHP (can also be due to ca). So the immediate next step is to drain the bladder a transurethral Foley catheter. If this fails suprapubic drainage can be done.', 'role': 'assistant'}]