pathophysiology
After invasion by bacteria, the fist line of defense in the lower urinary tract is complete evacuation by voiding. Inflammation in the bladder and urethral wall is apparent within 30 minutes of in vasion by a bacterial pathogen. Polymorphonuclear leukocytes rapidly migrate to the bladder wall, which becomes conpletely injected within 2 hours. Complete evacuation of bacteria from the urine. Urination not only removes bacteria and associated toxins contained in the urine, it also allows more efficient destruction of the bacteria remaining on the thin film of urine that is closely adherent to the vesical wall.
Recurrent infection of the urinary bladder predisposes the individual to transient episodes of VUR. After resolution of the infection the reflux is not detectable on voiding cystourethrography(VCUG). Although it is known that certain adherent bacteria promote urinary system dilation,the relationship between bladder wall inflammation and ureterovesical junction competence remains unclear (Walsh, Retik, Vaughan, and others, 1998).