Urinary reflux

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Key points to remember

  • urinary reflux is also called vesico-ureteric reflux
  • it is the abnormal flow of urine back up the tubes (ureters) to the kidneys when a child wees
  • if a baby or child has urinary reflux, they may be at risk of UTIs (urinary tract infections) - recurrent UTIs may cause scarring and damage to their kidneys
  • it is important to watch out for the signs of a UTI in your child with urinary reflux
  • if you suspect that your child may have a UTI, go to your family doctor for a urine test
  • in most children the problem is easily managed and resolves as the child grows

It may help to read this fact sheet together with the following pages on this website:

What is the urinary tract and how does it normally work?

The urinary tract is the kidneys, ureters, bladder, and urethra.

The kidneys filter and remove waste and water from the blood to produce urine. The urine travels from the kidneys down 2 narrow tubes called the ureters. The urine is then stored in the bladder.

When your child wees, urine flows out of the body through the urethra, a tube at the bottom of the bladder. The opening of the urethra is at the end of the penis in boys and in front of the vagina in girls.

Urinary tract front
Urinary tract side male
Urinary tract female side
Figure 1. Front view of urinary tract
Figure 2. Side view of male urinary tract
Figure 3. Side view of female urinary tract

What is urinary reflux?

Urinary reflux is the abnormal flow of urine back up the ureters when a child wees. This can happen because the ureters may not close off when urine is being squeezed out of the bladder when your child wees. Normally when the bladder empties, all the urine flows out of the bladder through the urethra.

There are different degrees of severity of urinary reflux, graded from 1 to 5. Grade 1 is the mildest form, while grade 5 is the most severe.

normal kidney, ureter, and bladder

grade I vesicoureteral reflux

grade II vesicoureteral reflux

Normal kidney, ureter, and bladder Grade I urinary reflux:
urine (shown in blue) refluxes part-way up the ureter
Grade 2 urinary reflux:
urine refluxes all the way up the ureter

grade III vesicoureteral reflux

grade IV vesicoureteral reflux

grade V vesicoureteral reflux

Grade 3 urinary reflux:
urine refluxes all the way up the ureter with some widening (dilatation) of the ureter and the part of the kidney where urine collects (calyces)
Grade 4 urinary reflux:
urine refluxes all the way up the ureter with marked widening of the ureter and the part of the kidney where urine collects
Grade 5 urinary reflux:
massive reflux of urine up the ureter with marked twisting and widening of the ureter and the part of the kidney where urine collects

What are the signs and symptoms of urinary reflux?

  • urinary reflux does not cause any symptoms in affected babies or children
  • the most common sign of urinary reflux is a UTI
  • if your child has urinary reflux, it is important to watch out for the signs of a UTI in your child
  • if you suspect that your child may have a UTI, go to your family doctor for a urine test 
  • another sign of urinary reflux is a widened (dilated) urinary tract detected on ultrasound scan; this can sometimes be diagnosed before a baby is born when the mother has an ultrasound scan in pregnancy

How is urinary reflux diagnosed?

There are a variety of tests your doctor may request to diagnose urinary reflux and assess the condition of your child's kidneys and drainage tubes:

  • MCU (micturating cysto-urethrogram) - see the MCU page on this website
  • renal ultrasound scan - see the Renal ultrasound scan page on this website
  • DMSA renal scan - see the DMSA renal scan page on this website

What are the complications of urinary reflux?

  • urinary reflux may increase the chance of your child getting UTIs because of the faulty drainage of urine
  • urinary reflux alone does not usually cause kidney damage but recurrent UTIs in children with urinary reflux may cause kidney damage and scarring and can affect how well the kidneys work.

Only a small proportion of children with urinary reflux develop significant kidney problems. In most children the problem is easily managed with appropriate treatment and monitoring.

What treatment is required if my child has urinary reflux?

Urinary reflux usually gets better by itself as your child grows, especially if it is mild.

The treatment is aimed at preventing UTIs while your child is young, when they can cause damage to the kidneys. Sometimes, a small dose of antibiotics is prescribed at night to prevent UTIs until the urinary reflux improves or resolves by itself. In most children, no treatment is necessary and your child's doctor will monitor the growth and health of your child's kidneys with scans. This will depend on the severity of your child's reflux.

Regular urine tests may be necessary to make sure there is no infection present. If your child develops any symptoms of a UTI while on antibiotics, you should take them to your family doctor for an immediate urine test.

Will long term follow up be needed?

In most children, urinary reflux resolves completely in childhood and they have no future problems.

Urinary reflux may be associated with abnormal development of the kidneys resulting in a condition known as dysplasia. Kidney dysplasia causes reduced function in the affected kidney. Children with reflux and dysplasia will need to have their blood pressure measured every year.

Acknowledgements

This fact sheet has been adapted from:

  • Paediatric Outpatient Department. Christchurch Hospital. Canterbury District Health Board. 2002. Urine infections and ureteric reflux.
  • Children’s Unit. Waikato District Health Board. 1997. Your child with urinary reflux.

Graphics
Graphics of the urinary tract reproduced from NKUDIC (the National Kidney and Urologic Diseases Information Clearinghouse), United States. (These images are in the public domain; reproduction permitted).
Website: http://kidney.niddk.nih.gov/

Graphics of a normal kidney, ureter and bladder and grades 1 to 5 reflux reproduced from Texas Pediatric Surgical Associates website (no longer available) with permission.

This page last reviewed 28 May 2015
© Paediatric Society of New Zealand and Starship Foundation 2005 – 2015
Printed on 06 July 2015. Content is regularly updated so please refer to www.kidshealth.org.nz for the most up-to-date version
Content endorsed by the Paediatric Society of New Zealand