VESICOURETERAL REFLUX

What is vesicoureteral reflux? (VUR)

The normal urination process involves bladder contraction and urine flow out of the body through the urethra.

With vesicoureteral reflux (VUR), some urine goes back up into the ureters and possibly up to the kidneys. This process exposes the kidneys to infection.

In children, especially those in the first 6 years of life, urinary infection can cause kidney damage. The injury caused by infection to the kidney may result in scars in the kidney and loss of future growth potential or widespread scarring and loss of the normal kidney tissues. Even a small area of scarring in one kidney may be a cause of high blood pressure later in life. Untreated, severe reflux on both sides can result in kidney failure requiring dialysis or kidney transplantation.

VUR is most commonly diagnosed in infancy and childhood after the patient has a urinary tract infection (UTI). About one-third of children with a UTI are found to have VUR.

VUR can lead to infection because urine that remains in the  urinary tract provides a place for bacteria to grow. But sometimes the infection itself is the cause of VUR.

There are undetermined genetic risk factors which may affect the development of VUR. About 34% of patients who have the condition have siblings who are also affected.

Types of VUR:

Primary reflux

The most common cause for primary reflux in children is an abnormality in the section of the ureter that enters the bladder ( intravesical ureter). The intravesical ureter may not be long enough to enable the ureter to sufficiently act as a valve to prevent urine reflux, or the ureter may be inserted abnormally into the bladder.

Other causes of primary reflux include abnormalities in muscle of the bladder, abnormalities in the location of the urethral opening and abnormalities in the shape of the urethral opening. 

Secondary reflux

Secondary reflux is often caused by urinary tract infection which causes inflammation and swelling of the ureter. UTI may cause vesicoureteral reflux or vesicoureteral reflux may promote the growth of bacteria in the urinary tract, causing UTI.

Secondary reflux may also be caused by urinary tract abnormalities like narrowing of the ureter; duplicated ureters; ureterocele) and obstructions from stones or tumors. 



Evaluation

An ultrasound of the kidneys and bladder is done to 1) evaluate hydroneprosis and kidney growth and 2) detect abnormalities that cause reflux.

A renal scan is done to evaluate kidney growth and detect presence of scarring.

A voiding cystourethrogram (VCUG) is performed to determine if an abnormality in the urinary tract is causing reflux. A contrast dye is instilled into the bladder through a catheter and a series of x-rays are taken.

Grading of VUR

Grade I (least severe) to Grade V (most severe):

• Grade I results in urine reflux into the ureter only.
• Grade II results in urine reflux into the ureter and the renal pelvis, without swelling of the top of the ureter (hydronephrosis).
• Grade III results in reflux into the ureter and the renal pelvis, causing mild hydronephrosis.
• Grade IV results in moderate hydronephrosis.
• Grade V results in severe hydronephrosis and twisting of the ureter

Mild-to-moderate degrees of reflux (grades I to III) have a good chance of spontaneous resolution with age in over 80% of children. This typically occurs over the span of few years. Unfortunately, we do not know exactly when the reflux will go away for a particular child.
The chance of spontaneous resolution of high grade reflux (IV to V) is much lower.

Treatment

1) Antibiotic prophylaxis for VUR Gr II-III
2) Endoscopic treatment for VUR Gr I-IV
3) Open surgery  for VUR Gr IV-V


Follow-Up
All patients with a history of reflux will have life long monitoring. Even if the reflux resolves, there is still risk of developing kidney insufficiency, hypertension, and pregnancy-related problems.This usually involves periodic visits to the pediatrician and have the following taken: height and weight, blood pressure, and urine analysis. Kidney function can be evaluated by blood tests (creatinine and BUN) or by creatinine clearance or glomerular filtration rate. Occasional ultrasound tests will ensure that kidney growth is on target for age. Female patients should be carefully monitored during their pregnancy.