12. this gentleman has worsening bilateral hydronephrosis. he did not have much of a post void residual on his bladder scan. he is taken to the operating room to have a bilateral cystoscopy and retrograde pyelogram. the results come back as gross prostatic hyperplasia with urinary retention as the cause of the hydronephrosis

52005, N40.0 and N13.39

Explanation:

52005 identifies a cystoscopy with bilateral ureteral catheterization  and injection of dye for a retrograde pyelogram (x-ray of the kidney and  ureter. N40.0 is the correct diagnosis code for hyperplasia of prostate.  Although the patient has hydronephrosis caused by the prostate  problem, there is no mention of lower urinary symptoms. N13.39  indicates "other" hydronephrosis. Hydronephrosis in this case is  caused by enlargement of the prostate, which causes urinary retention  with backup of urine to the kidneys.