Paediatrics: Vesicoureteric reflux

2021-03-04 12:00 AM

This is the retrograde flow of urine from the bladder into the upper urinary tract.

Vesicoureteric reflux

This is the retrograde flow of urine from the bladder into the upper urinary tract. VUR is usually congenital in origin, but maybe acquired (e.g. post-surgery). VUR combined with UTI leads to progressive renal scarring. Such reflux nephropathy may progress to end-stage renal failure if untreated. The incidence of VUR is 71% in newborn infants. It is observed in 30–45% of young children (<5yrs) presenting with UTI. There is often a strong family history with a 35% incidence rate among siblings of affected children. So called ‘congenital reflux’ is also now recognized as a result of routine antenatal scanning. This can result in small, smooth underdeveloped kidneys in otherwise asymptomatic children.

Grade of VUR

The extent of retrograde reflux from the bladder can be graded according to the International Reflux Study grading system:

  • I: into the ureter only.
  • II: into ureter, pelvis, and calyces with no dilatation.
  • III: with mild/moderate dilatation, slight or no blunting of fornices.
  • IV: with moderate dilatation of the ureter and/or renal pelvis and/or tortuosity of the ureter, obliteration of sharp angle of fornices.
  • V: gross dilatation, tortuosity, no papillary impression visible in calyces.

Diagnosis

The diagnosis of VUR is established by radiological techniques.

Micturating cystourethrogram

This technique involves urinary catheterization and the administration of radiocontrast medium into the bladder. Reflux is detected on voiding.

  • Advantages: grade of reflux seen.
  • Disadvantages: requires bladder catheterization, radiation dose.

Indirect cystogram

A radionucleotide method. Includes mercaptoacetyltriglycine (MAG-3) and diethylenetriamine pentaacetic acid (DTPA) scans.

  • Advantages: no catheterization required; lower radiation dose.
  • Disadvantages: false negatives found; co-operation of child to void is needed.

Follow-up and treatment

The aims are to prevent progressive renal scarring. Prophylactic antibiotics may be used to prevent this and imaging by indirect cystogram (e.g. MAG-3) and DMSA are sometimes used for follow-up. Randomized controlled trials of medical versus surgical treatment show surgery can reduce the incidence of pyelonephritis, but there is no difference in scarring compared with medical treatment.

Medical therapy

Antibiotic prophylaxis therapy

Surgery

Not routinely recommended. Indications for surgery include failed medical therapy or poor compliance.

  • ‘STING’ procedure (sub-ureteric Teflon injection): commonly used.
  • Endoscopic injection of materials behind the ureter to provide a valve mechanism during bladder filling and emptying. Longevity and the need for repeat treatments not fully known.
  • Open surgery: re-implantation of ureters.

Prognosis

  • Spontaneous resolution of VUR often occurs, especially with lower grades of reflux.
  • Bilateral reflux (grades IV and V) and reflux into duplex systems is associated with a lower probability of resolution.