Vesicoureteral reflux (VUR)

Vesicoureteral reflux (VUR) is the reverse flow (reflux) of urine back into the ureters and kidney from the bladder where urine is stored just before it is released from the body (urination). Normally, there should be no backflow of urine. This protects the kidney from any possible infected urine stored in the bladder. The abnormality in VUR is incompetent valves at the junction between the bladder and ureters. There is weakness of bladder at the site of ureteral entry and the trigone. This condition may lead to recurrent urinary tract infections UTI and inevitably infections of the kidney (pyelonephritiis). The ureteral orifices enter at the outer edges of a ridge, and this ridge forms the upper portion of the trigone.

This disorder is important to look for in children who have recurring urinary tract infections (UTI). This disorder will be the cause in 50% of children who have UTIs.

The ureters are two long muscular tubes which travel from the kidneys to the bladder. Normal ureteric parastalysis propels the urine forward into the bladder. As the ureter enters the bladder, it tunnels between muscle layers in the bladder. The ureters enter at an angle so part of the ureter is embedded into the bladder wall . It does not enter directly at 90 degrees, instead it enters to outer muscular layer of the bladder, tunnels in between the outer and inner muscular layers and then enters the bladder. This submucosal tunnel is believe to be the primary mechanism to prevent reflux; a shorter submucosal tunnel is more likely to result in VUR.

Signs and Symptoms

The symptoms of reflux can be categorized:

• Symptoms with a kidney infection - high fever, chills, pain in lower back, nausea and vomiting
• No symptoms with a kidney infection but the kidney infection is present
• Symptoms of a bladder infection (cystitis) - frequency in urination and burning on urination
• Later stages will show kidney damage including high blood pressure and decreased urine output

Causes

The major cause of VUR is weakness of the trigone and the ureteral musculature in the bladder wall. This can be due to several reasons.

• Trigonal Weakness - This the most common cause and usually occurs in young girls. Weakness on either one side or both leading to an inability to effectively close the ureter(s) due to decreased pressure
• Abnormalities of the ureter include a duplicate ureter from a single kidney. One of the ureters will not have the same protective entry into the bladder. Also, a ureter may enter the bladder at an abnormal spot and not into the appropriate trigonal area where the bladder is able to maintain the right pressure.
• Underlying disease may be the source of VUR. An obstruction of the urinary tract may cause reflux such as a spasm of the urethra in young females. Male boys develop recurrent UTIs because of an abnormaility of their urethra (posterior urethral valves). In older males, BPH can cause obstruction. Spinal cord diseases may also cause reflux because of neural damage to the bladder.

Diagnosis

On physical examination by a physician, a distended bladder may be felt in patients with spinal cord injuries. The patient with symptomatic pyelonephritis will have pain located in the flank area, and boys with posterior urethral valves will have a thickened bladder which may be felt during exam.

• Urinalysis - a urine sample will be taken and evidence of infection may be revealed with bacteria, white blood cells, and other markers of a UTI
• Blood testing - Unless kidney damage is present, testing of renal function should be normal. With renal failure, you will see an elevation of the creatinine. This should be performed especially if hydronephrosis, obstruction or renal scarring is present

Diagnostic Imaging

• Renal and bladder ultrasound is a non-invasive test to look for hydronephrosis, renal abnormalities and bladder abnormalities.
• Voiding cystourethrography is the diagnostic test for VUR. A radiopaque agent is inserted into the bladder through a catheter. Radiographs (X-rays) are taken during the filling and emptying phases.

Grading

Vesicoureteral reflux is graded using the classification by the International Reflux Study Committee

Treatment

More than half of children with VUR can be treated non-surgically while adults will require a surgical procedure. Resolution of reflux depends on the grade of reflux. While grade 1 reflux will spontaneously resolve in 90% of patients in 5 years, grade 4 reflux will resolve in approximately 50% of patients. Patients with grade 3 to 5 reflux are treated surgically. Patients who present at an older age, bilateral vesicoureteral reflux and voiding dysfunction are less likely to have spontaneous resolution.

• Non-surgical treatment - Almost all children with reflux are placed on prophylactic antibiotics. Patients with grade 1 or 2 reflux are often placed on prophylactic antibiotics and monitored.

• Surgical Options
  • Temporary urinary diversion - a surgical opening into either the bladder, ureter, or kidney that attaches to the skin to allow drainage of urine. This will eventually be reversed, and the patient will return to normal habits.
  • Ureteral reimplant - It is also called ureteroneocystostomy.
  • Injection of a bulking agent at the ureteral orifice.

• Definitive reasons to perform surgery are:
  • if it is impossible to keep the urine sterile and reflux continues
  • kidney infections persist despite chronic (long-term) use of antibiotics
  • kidney damage is apparent

• Relative reasons to perform surgery
  • Persistent reflux
  • Anatomic abnormalities, such as ectopic ureter, ureteral duplications, etc.
  • Age > 10
  • Poor compliance or inability to tolerate medical treatment

Related Problems

The reason this disorder is important to diagnose is because it can lead to permanent kidney damage in two ways.

• Pyelonephritis (kidney infection) - Continuous reflux of the urine can lead to recurrent kidney infections.

• Dilation of the ureter and portions of the kidney leads to reflux and the presence of any urine in the renal tissue for long term can lead to end-stage renal disease or renal failure.

Expected Outcome

All patients, including children and adults, have a very good prognosis. Those with fairly normal urinary tracts do well with conservative treatment, and those needing surgery also have good results. Only those who have significant kidney damage when they see a doctor are those who do not do quite as well. It is emphasized that when a child has recurrent UTIs that they should seek medical attention.

Notable Experts

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) conducts and supports research to help people with urologic diseases, including children. The NIDDK’s Division of Kidney, Urologic, and Hematologic Diseases (DKUHD) maintains the Pediatric Urology Program, which supports research into the early development of the urinary tract. The DKUHD currently supports several researchers working to evaluate current treatments for VUR, particularly the use of antibiotics to prevent infection.

American Urological Association Foundation
1000 Corporate Boulevard
Suite 410
Linthicum, MD 21090
Phone: 1–800–828–7866 or 410–689–3700
Email: patienteducation@auanet.org
Internet: www.urologyhealth.org