The kidneys filter waste products, excess fluids and solutes and other consumed substances from the blood to make urine. Urine then passes from the kidneys through the ureters (one for each of the two kidneys) to the bladder, where it is stored until it is released via the process of urination (also known as "voiding"). During voiding, urine is expelled from the bladder out through the urethra.
Each ureter enters the bladder at an angle and creates a tunnel between the layers of the bladder wall. This tunnel is generally about 1-2cm long. As the bladder fills, this tunnel becomes compressed, creating a valve that prevents urine from traveling back upstream (also known as "refluxing" up) the ureter.
Besides preventing urine from refluxing up the ureters, these valves also prevent bacteria from traveling up and infecting the kidneys and prevent the high pressures present within the bladder at the time of voiding from being transmitted up to the kidneys. The valves also ensure that all urine leaves the bladder through the urethra and out the body instead of just hanging around inside the body.
Why does reflux occur?
There are a number of reasons why urine may reflux back up the ureters. Most commonly, the tunnel created as the ureters pass through the bladder wall is not long enough to overcome the high voiding pressure of the bladder. In general, the length of ureter passing through the bladder wall must be two and a half (2.5) to four (4) times the diameter of the ureter in order for the valve to prevent reflux. In some children, this tunnel length will increase as the child grows, therefore creating a competent valve. If the ureter enters the bladder at an abnormal location (known as an ectopic ureter), the tunnel will likely be short and the valve incompetent. This is less likely to resolve with age. Other causes for reflux include posterior urethral valves, abnormal bladder function (neuropathic bladder, detrusor sphincter dyssynergia), duplicated collecting systems, ureterocele, infrequent voiding or constipation.
Why do we care about reflux?
When reflux occurs, the one-way street for urinary elimination becomes a two-way street that allows a simple route for bladder bacteria to reach the kidneys in children who are prone to bladder infections. VUR can become a serious medical concern in children who develop bacterial urinary tract infections because of this direct access to the kidney. If infected urine flows back into the kidney it has the potential to cause scarring of the kidney (also known as "atrophy") with possible long-term side effects of hypertension, proteinuria and renal insufficiency. The kidneys of children are especially susceptible to this damage and even partial damage can lead to high blood pressure later in life. Some causes of reflux may eventually lead to complete dysfunction of both kidneys, resulting in the need for dialysis or kidney transplantation. Reflux and the associated infections may also increase the risk for kidney stone formation. Because of the potential health risks associated with VUR and urinary tract infection (UTI), it is important to properly diagnose the severity of the reflux and to treat and prevent recurrent urinary infections. Fortunately, with modern management philosophies for VUR and UTI, the potential for long-term, significant side effects is a rare occurrence.
How do we evaluate for reflux?
For some patients, an ultrasound evaluation of both the upper and lower urinary tracts is all that is necessary to evaluate for the signs of reflux. If the results are inconclusive or suspicious for an abnormality, an intravenous pyelogram (IVP) may be performed. The exam routinely performed to evaluate for reflux is a voiding cystourethrogram (VCUG). A very small catheter is placed through the urethra into the bladder where a contrast material that is visible by x-ray is instilled. This allows us to see the contours of the bladder, any reflux up the ureters and any abnormalities that may be present in the urethra. X-ray exposure is minimal for the procedure. A similar procedure is a nuclear voiding cystogram in which a mildly radioactive material, producing even less radiation exposure than a typical x-ray, is instilled into the bladder instead of the contrast material. Your Pediatric Urologist can help determine which procedure is most appropriate for your child.
How common is reflux?
Peter D. Furness III, MD, FAAP, Associate Chief, Department of Pediatric Urology at The Children’s Hospital says,“VUR (Reflux) is the most common urinary tract problem occurring in children that can affect the kidneys. It affects approximately 1% of children (1 out of every 100 kids). Of girls with urinary tract infections, or UTIs, one third will have associated VUR. If they also have high fever, up to 50% will be diagnosed with reflux.”
What about my other children? Should they be tested?
When one of your children has reflux, any of his/her brothers and sisters have about a 33% (1 in 3) chance of also having or developing reflux, even though they may not have any symptoms. If your other children have previously had urinary tract infections the chances may be even higher. In fact, approximately half of all children with a urinary tract infection have reflux. Siblings under the age of seven (7) years old should have a complete reflux evaluation whereas older siblings should be screened with a simple urinalysis and ultrasound.
Non-Operative Management of Reflux
Any underlying problems that may be contributing to reflux, such as constipation, posterior urethral valves, infrequent voiding, etc. should be corrected and the reflux re-evaluated. Mild reflux will resolve over time in most children. For this reason, most children are given the chance to outgrow their reflux. During this time they are given antibiotic prophylaxis (preventative antibiotics) with a type of antibiotic we've shown to offer the best protection to infection with the least side effects. During this time, any fever or other symptoms suggesting a urinary tract infection must be evaluated aggressively with a urinalysis and urine culture to protect your child against a potentially dangerous "breakthrough urinary tract infection. Symptoms of a urinary tract infection may include burning, increased frequency of urination, straining to urinate, foul urine odor, bloody urine or incontinence (bed-wetting/pants-wetting) that is new or unusual for your child. After a period of about 1-2 years, the urinary system and kidney function are re-evaluated.
Surgical Correction of Reflux
When reflux fails to resolve, is high-grade (more severe), or is associated with breakthrough infections during a non-operative monitoring period, surgical correction is highly recommended to prevent damage to the kidneys. The procedure most commonly employed is called a ureteroneocystotomy and involves reimplanting the ureters in a manner that prevents reflux. In general, this is done by creating a new, longer tunnel for the ureter to pass through the bladder wall. Severely dilated ureters may be narrowed to allow for the necessary 4:1 tunnel length to ureter diameter ratio described above. As with all surgical procedures there is a risk of bleeding and infection. In addition, urinary leakage, bladder spasms, urinary obstruction and continued reflux are all possible risks. To put these risks into perspective, the success rate of the surgery has been shown to be around 95-98% and the risk of obstruction is only about 1-2%. After the operation your child will continue antibiotic prophylaxis until follow-up studies have confirmed that reflux has been resolved.
Intravesical Correction of Reflux (Deflux)
Until recently, the only two accepted treatments for younger children with vesicoureteral reflux were the two described above: long-term prophylactic antibiotic therapy and open surgery. The new injectable Deflux procedure involves a light anesthesia with the insertion of a fiberoptic camera into the bladder through the urethra (cystoscopy). Under telescopic vision, a small injection needle is positioned under the end of the ureter where the ureter enters the bladder. A small amount of “bulking” gel (Deflux) is injected. This buttresses the ureteral opening just enough so that urine no longer refluxes
Dr. Marty Koyle and a Pediatric Urology Fellow perform surgery to correct vesicoureteral reflux
back up to the kidneys, but still allows normal forward urine flow. The procedure takes about 15 minutes or less in the majority of cases. Used in children with mild to moderately severe reflux, the procedure corrects reflux 70-80% of the time. For the appropriate patients, the combined success rate for patients with one or more Deflux procedures is similar to that of surgery. This new procedure is changing the VUR treatment for children with low grades of reflux previously managed with long-term antibiotics.
Illustrations show the minimally invasive placement of Deflux material to treat vesicoureteral reflux.
Martin A. Koyle, MD, FAAP, FACS, Chairman of Pediatric Urology at The Children's Hospital, explains the advantages of the Deflux procedure, "The new minimally-invasive Deflux procedure helps kids avoid open surgery and surgical scars and eliminates the discomfort and radiation associated with repeated catheterizations and voiding cystourethrograms. Deflux minimizes the need for long-term antibiotics with their potential side effects."
Drs. Marty Koyle and Peter Furness have been closely involved in the investigation and the introduction of Deflux in the United States. Both surgeons have extensive experience with this new technique. Consequently, The Children’s Hospital has been chosen as one of 12 American centers to evaluate the Deflux technique in ongoing FDA trials. Drs. Furness and Koyle have been selected as instructors to teach the technique to other pediatric urologists nationally. For the second consecutive year, they have been chosen to host a national live surgical demonstration and conference to teach all graduating pediatric urologic fellows in North America.
All patients with reflux or corrected reflux should be monitored for recurrence or associated problems by periodic follow-up visits throughout their life. This usually only involves an occasional clinic appointment in which we can monitor for appropriate growth, normal blood pressure and adequate kidney function. Blood and Urine samples may be taken for simple tests that can tell us how the patient's kidneys are functioning and to ensure that there are no recurring urinary tract infections. On occasion, other tests such as ultrasound may be used to further evaluate the urinary system. Your Pediatric Urologist can help you determine how often your child should follow-up.
Pediatric Urologists Dr. Peter Furness and Dr. Marty Koyle perform a Deflux procedure
Why should I follow-up if my child no longer has reflux?
By the time reflux has been detected and treated, some kidney damage may have already occurred. Even patients who have had surgical correction of their reflux have a 20% (1 in 5) chance of developing a significant degree of high blood pressure (also known as hypertension) later in life. Other problems that are monitored for include kidneys that don't grow or function adequately and may worsen with age. The Pediatric Nephrologists (non-surgical kidney doctors) at the Children's Hospital may be included in the care of child if such kidney problems develop.
If you have any questions about VUR, infections and/or Deflux, please call 303-861-3926.