Vesicoureteral reflux (urinary reflux)

 

Vesicoureteral reflux (urinary reflux) is a childhood 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 (the ureterovesical junction) there is a valve mechanism.  As the bladder is being emptied these valves close, preventing urine from flowing backwards (refluxing) towards the kidneys.

 

With vesicoureteral reflux, urine flows from the bladder, through the valves at the ureterovesical junstion, back up the ureters and back into the kidneys. It is usually a congenital condition (present at birth) and occurs when one or both valve mechanisms are not working correctly.  The condition is more common in girls than boys.

Vesicoureteral reflux is graded 1 to 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 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 ureterovesical junctions mature as the child ages and most children with vesicoureteral reflux will grow out of the condition within a few years of birth. Spontaneous resolution of the condition is more likely to occur in children who have mild to moderate grade reflux. High-grade, severe reflux is less likely to spontaneously resolve.

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 UTIs have a normal urinary tract. However up to 30% of them have some degree of urinary reflux. Children who experience repeated UTIs 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:

Medications:
UTIs require prompt treatment with antibiotics to prevent infection developing in the kidneys.  In children who have recurrent UTIs, prophylactic (preventative) antibiotics may be recommended to prevent UTIs from developing, and hence prevent damage to the kidneys. Again, the health and growth of the kidneys will be regularly assessed with ultrasound scans.

Surgery:

Surgery to repair the valve mechanism at the ureterovesical junction is referred to as “ureteric reimplantation”. The surgery is performed under a general anaesthetic and may require a 2 or 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 rate of success for the treatment of vesicoureteral reflux.

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

O’Toole, M.T. (Ed.) (2013). Vesicoureteral reflux. Mosby’s Dictionary of Medicine, Nursing & Health Professions (9th ed.). St Louis, MI: Elsevier Mosby.
Mayo Clinic (2014). Vesicoureteral reflux (Web Page). Rochester, NY: Mayo Foundation for Medical Education and Research. http://www.mayoclinic.org/diseases-conditions/vesicoureteral-reflux/basics/definition/con-20031544 [Accessed: 22/09/17]
KidsHealth (2015). Urinary reflux (vesico-ureteric reflux) (Web Page). Auckland: Paediatric Society of New Zealand and Starship Foundation. https://www.kidshealth.org.nz/urinary-reflux [Accessed: 22/09/17]

 

Last reviewed -  September 2017