Vesicoureteral Reflux (VUR)

Vesicoureteral Reflux (VUR)

Lea este articulo en EspanolWe've all heard of acid reflux — when stomach acids move up into the esophagus and cause a burning sensation — but there can be other types of reflux in the body. When urine (pee) refluxes from the bladder to the kidneys, it's called vesicoureteral reflux (VUR).

Vesicoureteral (ves-ih-koe-yoo-REE-ter-ul) reflux happens when urine abnormally flows backward from the bladder into the ureters, thin tubes that connect the kidneys to the bladder. If backed-up urine reaches the kidneys, it can lead to infection, scarring, and even long-term kidney damage if left untreated. Fortunately, most kids with VUR don't have a severe case of it and outgrow it with no long-term complications.

Treatment depends on the severity of the condition. In mild cases, no treatment is necessary. Moderate to severe cases may be treated with antibiotic medicines to prevent infection. In cases where kids have infections and fevers along with the VUR, surgery may be needed.

How the Urinary Tract Works

The urinary tract is made up of two kidneys, two ureters, one bladder, and one urethra. Kidneys are fist-sized, bean-shaped organs in the back that filter excess fluids and waste products from the blood and turn them into urine. The urine then flows out of the kidneys through the ureters, which are long, thin tubes.

The ureters transfer urine to the bladder, a balloon-like organ that stores the urine until it's emptied during urination. While it's in the bladder, urine is prevented from flowing back into the ureters by valves in the bladder. During urination, it exits the body through the urethra, a tube at the bottom of the bladder.


Normally, urine flows from the kidneys to the bladder, but defects in one or both ureters can allow it to flow the other way. So can a blockage in the ureters or in the bladder.

When a defect causes the condition, it's called primary VUR. This is the most common type of VUR affecting kids. If a child is born with primary VUR, it means that a ureter didn't grow long enough while the baby was in the womb. This can affect the valve where the ureter enters the bladder. If the valve doesn't shut properly, urine can flow back up the ureters to reach the kidney. Primary VUR is believed to be a genetic condition.

If a blockage in the urinary tract obstructs the flow of urine and causes it to go back into the kidneys, it's called secondary VUR. Kids with this type of VUR often have reflux in both ureters. Secondary VUR can be caused by nerve damage, infection, or pressure on the ureter from another organ, such as an enlarged prostate.


Most of the time, VUR has no obvious signs or symptoms. It's often first detected when a child has a urinary tract infection (UTI) with a fever.

Symptoms of a UTI include:

lower tract infection (in the bladder)

upper tract infection (in the ureters or kidneys)

As kids get older, untreated VUR, along with any related UTIs, can lead to long-term problems caused by scarring of the kidney. These problems include:

In some cases, VUR may be detected before a baby is born during a routine prenatal ultrasound. An ultrasound uses sound waves to create an image of the baby in the womb. Ultrasounds can sometimes show if a baby has swollen kidneys (hydronephrosis), which could be a sign of VUR.


If your child has symptoms of a UTI, see a doctor right away. To check for VUR, the doctor will do a physical examination and ask you questions about your family medical history. Blood and urine tests may be done to see how well your child's kidneys are functioning and check for signs of infection or damage to the kidneys.

Doctors can use certain tests to confirm a diagnosis of VUR, such as:

If VUR is diagnosed, the doctor will grade the condition from I through V based on its severity, and use the grade to decide the best course of treatment. Grade I reflux is the mildest, with urine that backs up only as far as the ureters. Grade V reflux is the most severe and can involve twisting of the ureter and swelling of the kidney.


In many cases, kids with primary VUR outgrow it. As a child gets older, the ureter gets longer and straighter, and the valve where the ureter enters the bladder is able to shut correctly.

VUR that occurs with a UTI needs prompt antibiotic treatment to keep the infection from spreading to the kidneys. Kids who are put on antibiotics should take them for as long as prescribed, even if they start to feel better early on.

In moderate to severe cases of primary VUR with UTIs and fever, the doctor may recommend surgery. The most common type of surgery is ureteral reimplantation, in which one or both ureters are extended further into the bladder to correct the backflow of urine from the bladder to the ureters and kidneys. This type of surgery usually requires kids to spend a few days in the hospital while they recover.

Another surgical procedure, endoscopic injection, involves injecting a special gel into the bladder with the use of a catheter. The gel, placed near the valve at the opening of the ureter, prevents urine from going back into the ureter and helps the valve close properly. Most kids can leave the hospital on the same day that they have this procedure.

To treat a case of secondary VUR, antibiotics are given to fight infections and surgery might be done to remove the blockage causing the reflux.

Moderate to severe VUR, if not treated, can lead to serious health problems down the road. But with prompt treatment, long-term complications and damage to the kidneys can be prevented.

Reviewed by: Robert S. Mathias, MD
Date reviewed: March 2014

Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.

© 1995-2015 KidsHealth® All rights reserved.
Images provided by iStock, Getty Images, Corbis, Veer, Science Photo Library, Science Source Images, Shutterstock, and

Bookmark and Share

Related Resources
OrganizationNational Institute of Diabetes and Digestive and Kidney Diseases This group conducts and supports research on many serious diseases affecting public health.
OrganizationNational Kidney Foundation (NKF) NKF seeks to prevent kidney and urinary tract diseases, improve the health and well-being of individuals and families affected by these diseases, and increase the availability of all organs for transplantation.
Web SiteNephron Information Center The Nephron Information Center offers information about how the kidneys work, transplants, and links to other sites.
OrganizationAmerican Association of Kidney Patients (AAKP) The AAKP serves kidney patients and their families by helping them cope with the emotional, physical, and social impact of kidney failure.
Related Articles
Urinary Tract Infections A urinary tract infection (UTI) is one of the most common reasons that teens visit a doctor. Learn about the symptoms of UTIs, how they're treated, and more in this article.
Your Urinary System You pee every day, but what makes it happen? Find out in this article for kids about the urinary system.
Ultrasound: Renal (Kidneys, Ureters, Bladder) A renal ultrasound makes images of your child's kidneys, ureters, and bladder. Doctors may order this test if they suspect kidney damage, cysts, tumors, kidney stones, or complications from urinary tract infections.
Urinary Tract Infections Urinary tract infections (UTIs) are common in kids, but often can be prevented. Early detection and treatment are key.
Recurrent Urinary Tract Infections and Related Conditions Recurrent urinary tract infections can cause kidney damage if left untreated, especially in kids under age 6. Here's how to recognize the symptom of UTIs and get help for your child.
A to Z: Hematuria (Blood in Urine) Learn more about hematuria (blood in urine) and how it's treated.
Urinary Tract Infections (UTIs) You probably don't think much about urinating, or peeing. But what if it starts to sting? Find out more in this article for kids.
How the Body Works Main Page The human body is an amazing machine. Learn more about it through movies, quizzes, articles, and more.
Chronic Kidney Diseases Kidneys are about the size of your fist and shaped like beans. What happens when this important pair of organs doesn't work well? Find out in this article for kids.
When Your Child Has a Chronic Kidney Disease Parents of kids who have a chronic kidney disease often worry about what might happen next, how their child feels, and what treatments are likely to be involved. Find answers here.
Kidney Diseases in Childhood The kidneys play a critical role in health. When something goes wrong, it could indicate a kidney disease. What are kidney diseases, and how can they be treated?
Glomerulonephritis With glomerulonephritis, tiny filtering units in the kidneys stop working properly, causing problems like too much fluid in the body and swelling. Most of the time it can be treated. Find out more.
Blood in the Urine (Hematuria) Hematuria is pretty common, and most of the time it's not serious. Find out what causes blood in the urine and what to do about it.
X-Ray Exam: Voiding Cystourethrogram (VCUG) A VCUG can help evaluate the bladder's size and shape, and look for abnormalities, such as a blockage. It can also show whether urine is moving in the right direction.
Ultrasound: Abdomen Doctors order abdominal ultrasounds when they're concerned about symptoms such as abdominal pain, repeated vomiting, abnormal liver or kidney function tests, or a swollen belly.
Urine Tests Is your child having a urine culture or urinalysis performed? Find out why urine tests are performed, and what to expect when the doctor orders them.
Kidneys and Urinary Tract The bean-shaped kidneys, each about the size of a child's fist, perform several functions essential to health. Their most important role is to filter blood and produce urine.
Kidneys and Urinary Tract The kidneys perform several functions that are essential to health, the most important of which are to filter blood and produce urine.
Your Kidneys You need at least one kidney to live. Find out why in this article for kids.
Glomerulonephritis Glomerulonephritis happens when tiny filtering units in the kidneys stop working properly. Most cases get better on their own or with treatment.
Developments Developments
Sign up for enewsletter
Get involved Get involved
Discover ways to support Akron Children's