Vesicoureteral Reflux

In vesicoureteral reflux, urine flows from the bladder back into the ureters and eventually into the renal pelvis or the parenchyma. When the bladder empties only part of what has been, stored, urinary tract infection (UTI) may result. This disorder is most common during infancy in boys and during early childhood (ages 3 to 7) in girls. Primary vesicoureteral reflux that results from congenital anomalies is most common in females and rare in blacks. Up to 25% of asymptomatic siblings of children with diagnosed primary vesicoureteral reflux also show reflux. Secondary vesicoureteral reflux occurs in adults.

Causes

There are two types of VUR.

1. Primary VUR
2. Secondary VUR

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

Secondary VUR occurs when there is a blockage anywhere in the urinary system. The blockage may be caused by an infection in the bladder that leads to swelling of the ureter. This also causes a reflux of urine to the kidneys.

Signs and Symptoms

• Urinary tract infection
• Nausea and vomiting
• Protein in the urine (proteinuria)
• Bedwetting
• Poor weight gain
• Failure to thrive

Diagnostic tests

The following studies are pertinent to the diagnosis of vesicoureteral reflux:

Clean-catch urinalysis shows a bacterial count over 100,000/ml, sometimes without pyuria. Microscopic examination may reveal red blood cells, white blood cells, and an increased urine pH when infection is active. Specific gravity less than 1.010 demonstrates inability to concentrate urine.

Elevated levels of serum creatinine (more than 1.2 mg/dl) and blood urea nitrogen (more than 18 mg/dl) demonstrate advanced renal dysfunction.

Voiding cystourethrography identifies the degree of reflux and shows when reflux occurs. It may also pinpoint the causative anomaly. In this procedure, contrast material is instilled into the bladder and X-rays are taken before, during, and after voiding.

Catheterization of the bladder after the patient voids is used to determine the amount of residual urine.

Excretory urography may show a dilated lower ureter, a ureter visible for its entire length, hydronephrosis, calyceal distortion, and renal scarring.

Cystoscopy, with instillation of a solution containing methylene blue or indigo carmine dye, may be used to confirm the diagnosis. After the bladder is emptied and refilled with clear sterile water, colortinged fluid from either ureter positively confirms reflux.

Radioisotope scanning and renal ultrasonography may be used to detect reflux and screen the upper urinary tract for damage secondary to infection and other renal abnormalities.

Treatment

The goal of treatment in a patient with vesicoureteral reflux is to prevent pyelonephritis and renal dysfunction through antibiotic therapy and, when necessary, vesicoureteral reimplantation. Appropriate surgery creates a normal valve effect at the junction by reimplanting the ureter into the bladder wall at a more oblique angle.

Antibiotics usually are effective for reflux that is secondary to infection, reflux related to neurogenic bladder and, in children, reflux related to a short intravesical ureter (which disappears sponcimeously with growth). Reflux related to infection usually subsides after the infection is cured, but 80% of females with vesicoureteral reflux have recurrent UTls within a year. Recurrent infection requires long-term prophylactic antibiotic therapy and careful patient follow-up (voiding cystourethrography and excretory urography every 4 to 6 months) to track the degree of reflux.

UTI that recurs despite prophylactic antibiotic therapy necessitates vesicoureteral reimplantation. In the patient with neurogenic bladder, other treatments may be more effective in preventing reflux. These patients may benefit from transurethral sphincterotomy (to relieve the obstructed outlet) or from bladder capacity augmentation (to decrease intravesical pressure).

After surgery (as after antibiotic therapy), close medical follow-up is necessary (excretory urography every 2 to 3 years and urinalysis once per month for a year) even if symptoms haven't recurred.