Topic Overview

What is vesicoureteral reflux (VUR)?

Vesicoureteral reflux (VUR) is the backward flow of urine from the bladder into the kidneys. Normally, urine flows from the kidneys through the ureters to the bladder. The muscles of the bladder and ureters, along with the pressure of urine in the bladder, prevent urine from flowing backward through the ureters.

VUR allows bacteria, which may be present in the urine in the bladder, to reach the kidneys. This can lead to kidney infection, scarring, and damage.

What causes vesicoureteral reflux?

There are two types of VUR:

• Primary VUR is present at birth. It is caused by a defect in the development of the valve at the end of the tube that carries urine from the kidneys to the bladder (ureter). This is the most common type of VUR and is usually detected shortly after birth.
• Secondary VUR occurs when an obstruction in the bladder or urethra causes urine to flow backward into the kidneys. Secondary VUR can occur at any age and can be caused by surgery, injury, a pattern of emptying the bladder that's not normal, or a past infection that puts pressure on the bladder. It is more common in children who have other birth defects, such as spina bifida.

What are the symptoms?

A urinary tract infection (UTI) can be a symptom of VUR. About one-third of children who are diagnosed with a UTI have VUR.¹ Symptoms of a UTI may include fever, pain or burning with urination, frequent urination, and the feeling that the bladder does not empty completely. Fever may be the only symptom of a UTI in a small child. So a urinary tract infection should be suspected in any child who has a high fever without an obvious cause.

How is VUR diagnosed?

VUR is usually diagnosed when a urinary tract infection (UTI) is suspected. Your doctor will ask about the history of your child's symptoms and do a physical exam.

The following tests may be recommended if UTI is suspected:

• A urine culture, to check for a UTI
• Ultrasound of the kidneys. This test uses sound waves to find out the size and shape of the kidneys. It can't detect reflux.
• Cystourethrogram (cystogram) after the UTI has been treated. This test can detect VUR and help find out if it's mild or severe. The voiding cystourethrogram, for example, uses an X-ray to take pictures of the urinary tract. The bladder is filled with dye, and pictures are taken of the bladder as it fills and empties.