Vesicoureteral reflux (VUR)

Vesicoureteral reflux, often shortened to VUR, is a condition where urine travels back up from the bladder, into one or both ureters and in severe cases, all the way back up to the kidneys. It happens when the valve that usually prevents urine from flowing backwards from the bladder is weakened or isn’t working properly. 

Urine is a waste product and it is not supposed to flow back up through the urinary system. Urine passing back through the urinary tract can cause problems such as infection and damage to the kidneys. 

VUR is graded from grade 1 to grade 5, with grade 1 being the mildest form, where urine flows from the bladder back only to the ureters, and grade 5 being the most severe, where the urine flows all the way up to the kidneys and causes significant stretching of the ureters and kidneys. More than 80% of VUR cases are graded as 2 or higher, which means that in most cases, the condition is moderate to severe. 

Doctors use this grading system to help them propose the best treatment options.

How common is vesicoureteral reflux?

VUR is present in about 2% of all newborn babies. Only a few children have noticeable symptoms. As children grow older and the bladder matures, diagnosis of this condition becomes less common. 

VUR is sometimes found during a medical test such as a scan being carried out for other symptoms or another medical condition. It is more commonly seen in children who have congenital differences in their kidneys or other part of their urinary system, such as those with duplex kidney, ureterocele and ectopic ureters. 

Duplex kidney (also called ureteral duplication, is where one or both kidneys have an extra ureter. 

Ureterocele is where the lower part of the ureter becomes enlarged, forming a balloon-like structure inside the bladder. 

An ectopic ureter is where the ureter attaches elsewhere in the urinary tract or bladder.

VUR is found to be the cause in 30-50% of children who have medical tests carried out for recurrent UTIs. 

If your child is diagnosed with VUR, their doctor will advise you if any treatment or further investigation is needed.

What are the symptoms of vesicoureteral reflux?

Usually, vesicoureteral reflux doesn’t cause any noticeable symptoms, but the most common is a UTI. In young children and babies, a UTI can be challenging to identify. The most common sign is a high fever. Alternatively, they may seem irritable or off their food. 

In older children, signs of a UTI are easier to spot and include a burning sensation while peeing, having to pee a lot, cloudy or foul-smelling urine, and abdominal discomfort. An older child will also be able to better communicate with you about their symptoms.

If your child does have a UTI, your doctor will prescribe antibiotics. If you suspect your child has a UTI, it is important to see a doctor promptly for treatment. Untreated infections can spread up to the kidney and cause serious infections.

How problematic is vesicoureteral reflux?

Children with VUR may experience repeat urinary infections, which require treatment and investigation as repeat infection can cause kidney damage. Your child’s doctor will be able to advise you about how severe their VUR is and how to manage the condition. 

To grade your child’s VUR, doctors use a range of medical tests, to assess their renal (kidney or urinary) function in further detail. These tests include scans such as dimercaptosuccinic acid renal scanning (DMSA) which is a type of scan that involves a safe tracer dye being injected into your child’s arm. This dye works its way through the bloodstream and into the kidneys and it causes any scarred areas to glow up on a scan, so that doctors can check to see whether VUR has caused any damage to your child’s kidneys. 

The results of tests such as this are used by doctors to diagnose and grade VUR and to work out how best to treat it. Further testing may be needed if initial tests and scans are unable to provide all the information needed for the doctor to make a diagnosis. This includes tests to rule out other medical conditions. 

Your child’s doctor will discuss any testing that is necessary to make a diagnosis, at each stage, with you so that you understand what tests are being proposed, why and what they entail, as well as if there are any risks involved.

This chapter contains general information about vesicoureteral reflux (VUR). It is not a substitute for professional medical advice or treatment. Always consult your doctor or healthcare provider for guidance on your individual medical situation.

Last updated: April 2025