Reduction in the length of the intravesical ureter associated with pyelonephritis in the adult pig.

The ureterovesical junction of pigs with cystitis and pyelonephritis was examined. There was significant shortening of the intravesical portion of the ureter in sows with pyelonephritis. In cases associated with acute pyelonephritis the ureteric orifice was found to be significantly wider than that found in the normal population. The ratio of the intravesical length to the ureteric orifice diameter was also significantly reduced. It is postulated that these changes to the ureterovesical junction originate or are caused by the disease processes in the bladder and may allow vesicoureteric reflux to occur, leading to ascending pyelonephritis.