ABSTRACT
Vesicoureteric reflux (VUR) may be defined as a permanent or intermittent intrusion of bladder urine into the upper urinary tract due to a defective ureterovesical junction. The defect in the ureterovesical junction may be a primary disorder or may arise secondary to bladder dysfunction (neuropathic bladder, dyssynergic bladder) or bladder outlet obstruction (posterior urethral valve). The refluxing urine can fill the upper excretory system (ureters and renal pelvis) between and/or during micturition, and can sometimes penetrate into the renal substance (intrarenal reflux). The volume of refluxing urine can vary in the same patient at different times. Attempts to classify the degree of reflux are therefore of limited practical interest, as reflux may change in intensity in individual patients.
