Medical terminology

Translate definitions into simple terms and insert them into the story:
Smaller subs had taken similar voyages in years prior and they had been equipped with diuretics, which carried them smoothly through the renal system. This patient was known for his hydronephrosis and after an intravenous pyelogramwas performed the way was cleared for the sub to travel to see what was the problem. This patient initially experienced oliguria which made it hard for the sub to pass through but finally enuresis was achieved!  The team noted the presence of renal calculi, but the team had to be cautious that the patient was not undergoing a concurrent lithotripsy, which would crack the hull of the sub.  The kidney was mildly irritated by the sub’s journey thus experiencing prerenal azotemia and pyelonephritis but thankfully no nephrosclerosis resulted.