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Vesicoureteral reflux in children

Vesicoureteral reflux (urinary reflux) is a condition in which urine flows from the bladder, back towards or into the kidneys. The refluxing urine increases the pressure within the kidneys and may contain bacteria that can lead to kidney infection. Long term increased pressure and repeated infections can lead to damage and scarring of the kidneys (known as kidney dysplasia), potentially interfering with kidney development and kidney function later in life.

Vesicoureteral reflux occurs in approximately one in 100 children. The majority of children with the condition will not require any treatment and will grow out of the condition in childhood; however a small number will require surgery to correct the condition.

General information

The urinary tract is made up  of the kidneys, the ureters, the bladder and the urethra. Urine produced by the kidneys flows to the bladder via the ureters. The bladder acts as a reservoir for the urine until it is excreted from the body via the urethra.  At the junction where each ureter enters the bladder, there is a valve mechanism.  As the bladder is being emptied these valves close, preventing urine from flowing backwards towards the kidneys.
With vesicoureteral reflux, urine flows from the bladder, through the valves at the junction of the bladder and the ureter, back up the ureters and back into the kidneys. It is usually a congenital condition (present at birth) and occurs when one or both of the valve mechanisms are not working correctly.  The condition is more common in girls and boys.

Vesicoureteral reflux is graded 1 – 5, with 1 being the mildest and 5 being the most severe:
Grade 1 - Urine refluxes part way up the ureter towards the kidney
Grade 2 - Urine refluxes all the way up the ureter and into to the kidney
Grade 3 - Urine refluxes all the way up the ureter and into the kidney. There is some widening (dilatation) of the ureter and the part of the kidney where urine collects
Grade 4 - Urine refluxes into the kidneys and there is marked widening of the ureter and the part of the kidney where urine collects
Grade 5 - Large amounts of urine reflux into the kidneys and there is marked twisting and widening of the ureter and the part of the kidney where urine collects
The valves at the junction of the ureters and the bladder mature as the child ages and approximately 70% of children with vesicoureteral reflux will grow out of the condition within a few years of birth. This is more likely to occur in children who have mild to moderate grade reflux. High-grade, severe reflux is less likely to spontaneously resolve.

Signs and symptoms

Vesicoureteral reflux in itself does not produce any symptoms. These occur when infection of the urinary tract (UTI) is present. Infection causes symptoms such as fever, pain, unpleasant smelling urine and a burning sensation when urinating.  Other symptoms commonly experienced include: 

  • Bedwetting (nocturnal enuresis).
  • Lower abdominal pain.
  • Blood in the urine (haematuria) and/or pus in the urine (pyuria)


Vesicoureteral reflux may be suspected before a baby is born. If prenatal ultrasound scanning shows enlargement of the kidney(s) and/or dilation (widening) of the ureter(s), it may indicate that reflux is occurring.

Vesicoureteral reflux is most commonly first suspected in infancy with the occurrence of repeated urinary tract infections. Most children who experience urinary tract infections have a normal urinary tract. However up to 30% of them have some degree of urinary reflux. Children who experience repeated urinary tract infections should be investigated for vesicoureteral reflux.   As the condition can run in families, there is a chance that a child’s siblings may also be affected by vesicoureteral reflux. It may be suggested that they are screened to rule this out.  Common investigations used to diagnose vesicoureteral reflux and assess for kidney damage include:

Ultrasound Scanning:
The bladder and kidneys are scanned to survey the anatomy and assess for any irregularities.

Micturating Cystourethrogram (MCU):
A small tube (catheter) is put into the child’s bladder and a radio-opaque (visible on x-ray) liquid is passed into the bladder. X-rays are taken as the bladder fills and as the child urinates.

DSMA Renal Scan:
Pictures of the kidneys are taken with a specialised scanner following the injection of a weak radioactive solution (radioisotope) into the bloodstream via a drip in the hand or arm. The pictures taken by the scanner can assess kidney size, position and function and check for scarring of the kidneys as the result of repeated UTI’s. 


The goal of any treatment for vesicoureteral reflux is to prevent damage to the kidneys. Treatment will depend on the severity of the reflux and whether there are ongoing problems with infection. In most cases, no treatment is necessary and the child's doctor will monitor the growth and health of the child’s kidneys with ultrasound scans. It may be recommended that the child has regular urine tests to make sure there is no infection present. If treatment for vesicoureteral reflux is required, there are two main treatment options:

In children who have recurrent UTI's, prophylactic (preventative) antibiotics may be recommended to prevent UTI's from developing, and hence prevent damage to the kidneys. Again, the health and growth of the kidneys will be regularly assessed with ultrasound scans.


Whilst surgery is no longer done routinely for vesicoureteral reflux, a small number of children will require surgery to correct the problem. This is particularly so for children with severe (grade 4 – 5) vesicoureteral reflux who have the following problems: 

  • They continue to develop UTI's while taking prophylactic antibiotics
  • The child is allergic to the antibiotics
  • The reflux does not resolve over time
  • The reflux worsens over time
  • The kidneys are showing signs of damage
Surgery to correct the valve mechanism at the junction of the ureter and bladder is referred to as “ureteric reimplantation”. The surgery is performed under a general anaesthetic and may require a 2 – 3 day stay in hospital.  During surgery the ureters are released and are then “reimplanted” into the bladder wall in such a way that an efficient valve mechanism is created. Prophylactic antibiotic treatment may be continued after surgery until follow up assessment shows that the reflux has resolved. Ureteric reimplantation has a very high (approximately 95%) rate of success for the treatment of vesicoureteral reflux.

Follow up 

After treatment for vesicoureteral reflux, follow up assessment may be recommended. This may involve urine tests, blood tests, ultrasound scanning, or MCU. Blood pressure and height and weight may also be measured. These tests aim to assess kidney function and to ensure that the reflux has resolved.

Further information and support

Kidney Kids is a group of New Zealand parents and children, who are dealing with kidney issues. Kidney Kids has support groups and contacts throughout New Zealand. 

Freephone: 0800 215 437

The New Zealand Kidney Foundation provides education and support about different kidney diseases. Their website provides details of patient support centres in New Zealand.

Freephone: 0800 KIDNEY / 0800 543 639


Anderson, K.N., Anderson, L.E. & Glanze, W.D. (eds.) (2006) Mosby’s medical, nursing, & allied health dictionary (6th ed.) St. Louis: Mosby-Year Book, Inc.
Davison, A.M., Cumming, A.D., Swainson, C.P. & Turner, N. (1999) Diseases of the kidney and urinary system. In C.Haslett, E.R. Chilvers, J.A.A. Hunter & N.A. Boon (eds.) Davidson’s principles and practice of Medicine (18th ed.) (pp417- 470) Edinburgh: Churchill Livingstone
Kidshealth (2013) Urinary reflux / VUR (vesico-ureteric reflux). The Paediatric Society of New Zealand and Starship Foundation. Auckland.
Last Reviewed -  11 July 2013
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