Urinary reflux review

What is vesicoureteral reflux (VUR)?

Vesicoureteral reflux (VUR), sometimes referred to as urinary or bladder reflux, is defined as the abnormal retrograde flow of urine from the bladder into the upper urinary tract through an incompetent ureterovesical junction.1

Low pressure reflux without bacterial contamination has not been documented to be harmful: however, reflux in the presence of infection is a risk factor for upper urinary tract infections (pyelonephritis).1 Untreated upper urinary tract infections have been shown to lead to acquired renal scarring (reflux nephropathy) in children.1

Congenital abnormalities of renal development may have associated vesicoureteral reflux resulting in a clinical picture of reflux nephropathy but without a history of urinary tract infection.1

Reflux nephropathy

Define as the following clinical triad1

  • Renal Scarring
  • Hypertension
  • Vesicoureteral Reflux

Vesicoureteral Reflux (Urinary Reflux)

  • May potentiate febrile UTIs
  • Significant risk factor for UTI
  • Commonly discovered during evaluation for UTI
  • Diagnosed with a voiding cystourethrogram (VCUG)
  • In presence of infection, could lead to long-term kidney disease

Classification of reflux

Primary reflux1
Primary reflux occurs as a result of a congenital deficiency in the formation of the ureterovesical junction in the absence of any other predisposing pathology.

Secondary reflux1
Secondary reflux occurs as a result of other urinary tract anomalies that secondarily cause a decomposition of a normally formed ureterovesical junction: neurogenic bladder, obstruction, infection, bladder and bowel dysfunction (BBD).


  1. Baskin LS, Kogan BA, Stock JA. Handbook of Pediatric Urology Third Edition. Philadelphia, PA: Wolters Kluwer; 2019.