Vesico-ureteric reflux (VUR)

Vesico-ureteric reflux (VUR) describes abnormal backflow of urine from the bladder into the ureter and the kidney. It is one of the most common abnormalities of the renal tract, predisposing to infection. and necessitating thorough investigation of childhood urinary tract infection (UTI).

• reported prevalence of VUR varies from 1.3% of healthy children to 8% to 50% of children evaluated after UTI (1)
  • newborns and infants, the incidence of VUR diagnosed after UTI is 36% to 49%
  • children with VUR detected after UTI are predominantly female

The international grading system of VUR:

• Grade 1: Reflux only into the non-dilated ureter.
• Grade 2: Reflux into the ureter and the renal pelvis without dilatation
• Grade 3: Reflux with mildly dilated ureter and pyelocalyceal system
• Grade 4: Reflux with the tortuous and moderately dilated ureter with blunting of renal fornices. The papillary impression is preserved
• Grade 5: Reflux with the tortuous and severely dilated ureter, dilatation of pyelocalyces with loss of fornices, and papillary impression

This process can lead to scarring and destruction of the kidney:

• renal scarring associated with VUR may be congenital in origin, which is also called congenital reflux nephropathy (RN) (1)
  • renal scarring that results due to acute pyelonephritis is called acquired RN
  • congenital RN is more common in boys, whereas the acquired RN is more common in girls
  • in most children, renal scarring may not be clinically significant
    • hypertension occurs in 10% to 30% of children and young adults and 34% to 38% of adults with renal scarring
      • in a follow-up period lasting 15 years in pediatric patients with renal scarring, about 13% at age 20 to 31 years were hypertensive

Antibiotics prophylaxis in infants with Grade III, IV, or V VUR (2):

• RCT (n=292 age 1-5 months with no previous UTI) found continuous antibiotic prophylaxis for 2 years reduced the occurrence of a first UTI vs no treatment (31 [21.2%] vs 52 [35.6%] patients, HR 0.55, 95%CI 0.35-0.86, NNT = 7)
• serious adverse events were similar across the group
• note that the trial was neither blinded nor placebo-controlled, and four different antibiotic options were used for continuous antibiotic prophylaxis

Reference:

• Mattoo TK, Mohammad D. Primary Vesicoureteral Reflux and Renal Scarring. Pediatr Clin North Am. 2022 Dec;69(6):1115-1129.
• Morello M et al. Antibiotic Prophylaxis in Infants with Grade III, IV, or V Vesicoureteral Reflux. NEJM September 14th 2023.