How is Vesicoureteral Reflux Diagnosed?

In some cases VUR is found in testing before birth. Most often it is found in children when they are 2 to 3 years old. But it may be seen at any age, even in babies or older children. About 3 out of every 4 children treated for reflux are girls. VUR is most often found when a child has a UTI.

Reflux is found with a test called a voiding cystourethrogram (VCUG), which is an X-ray of the bladder. It takes about 15 to 20 minutes, and involves:

  • Placing a catheter (a thin plastic tube) in the urethra
  • Injecting fluid with an X-ray dye through the tube until the bladder is full
  • Asking the child to pass urine
  • Taking pictures of the bladder to see if the dye goes backward up to 1 or both kidneys
  • Sometimes adding a small amount of radioactive tracer in the fluid and using a special camera

Infection linked to using a catheter for these tests occurs in a few children, so the urologist may suggest using antibiotics before and after the test.

Ways to ease pain and worry about using the catheter should be discussed with the doctor. Some children become upset and need to be held during the test. In some medical centers the study can be done with light sedation. Using general anesthesia may lead to incomplete test results because the doctor needs to see whether there is reflux when the child is voiding.

If reflux is found, further imaging tests may be done to check how well the kidneys are working and to look for kidney damage. In some cases, ultrasound of the kidneys and bladder may be done to check the size of the kidneys.

How is VUR Measured?

The doctor looks at an X-ray of the urinary tract to find out the reflux grade. This shows how much urine is flowing back into the ureters and kidneys, and helps the doctor decide what type of care is best.

In children with reflux and UTI, kidney damage may occur. Higher grades of reflux are linked to a greater risk of kidney damage.

The most common system of grading reflux (the International Study Classification) includes 5 grades:

VUR Grading Stages
VUR Grading Stages
Image © 2003 Fairman Studios, LLC

  • Grade I: urine reflux into the ureter only
  • Grade II: urine reflux into the ureter and the renal pelvis (where the ureter meets the kidney), without distention (swelling with fluid, or hydronephrosis)
  • Grade III: reflux into the ureter and the renal pelvis, causing mild swelling
  • Grade IV: results in moderate swelling
  • Grade V: results in severe swelling and twisting of the ureter

Risk of Kidney Damage

Children with reflux undergo a careful urological history and physical exam to find out the level of risk for kidney damage. This helps in the decision about the type of treatment.

The doctor will ask about important information, such as:

  • Whether the child is passing urine regularly
  • Whether the child has normal bladder control during the day
  • Whether the child empties his or her bladder fully
  • Whether the child has constipation

Many children with reflux have "dysfunctional elimination syndrome" or "bowel-bladder dysfunction." This happens when the child does not void often or fully. These children have a greater risk of kidney infection with reflux. On the other hand, in children with normal bladder control, normal kidneys and lower grades of reflux, the risk of kidney infection seems lower.