Vesicoureteral Reflux (VUR): When Urine Flows the Wrong Way

Vesicoureteral reflux (VUR) is a condition where urine flows backward from the bladder into one or both ureters (the tubes that normally carry urine from the kidneys to the bladder). This abnormal flow can increase the risk of urinary tract infections (UTIs) and, in severe cases, potentially lead to kidney damage over time.

Normally, a one-way valve at the junction where the ureter enters the bladder prevents urine from flowing back up towards the kidneys. In individuals with VUR, this valve doesn't function properly, allowing reflux to occur.

Understanding the Grades of VUR

VUR is typically graded on a scale of I to V, based on how far back into the ureters the urine refluxes and whether there is any dilation (widening) of the ureters or the part of the kidney that collects urine (renal pelvis):

• Grade I: Urine refluxes only into the ureter and does not reach the kidney. The ureter appears normal.
• Grade II: Urine refluxes up to the kidney but does not cause dilation of the renal pelvis or calyces (the cup-like structures that collect urine in the kidney). The ureter may appear slightly dilated.
• Grade III: Urine refluxes up to the kidney and causes mild to moderate dilation of the ureter and/or the renal pelvis and calyces. There is minimal blunting (rounding) of the sharp angle of the calyces.
• Grade IV: Urine refluxes up to the kidney and causes moderate dilation and tortuosity (twisting) of the ureter and moderate dilation of the renal pelvis and calyces with some blunting of the sharp angle of the calyces.
• Grade V: Urine refluxes up to the kidney and causes gross dilation and tortuosity of the ureter and gross dilation of the renal pelvis and calyces with loss of the papillary impressions (the tips of the renal pyramids that project into the calyces).

Lower grades (I and II) are generally considered mild, while higher grades (III, IV, and V) are more severe.

Causes of Vesicoureteral Reflux

VUR can be present at birth (primary VUR) or develop later due to another condition (secondary VUR):

• Primary VUR: This is the most common type and is often due to a defect in the development of the ureterovesical junction (where the ureter joins the bladder). The ureter may be too short or improperly positioned in the bladder wall, leading to a malfunctioning valve. Primary VUR often has a genetic component and can run in families. Many children with primary VUR outgrow the condition as the ureterovesical junction matures.
• Secondary VUR: This type is caused by an underlying problem that increases pressure within the bladder, leading to backward flow of urine. Causes of secondary VUR can include:
  • Neurogenic bladder: A condition where nerve damage affects bladder function.
  • Bladder outlet obstruction: Blockage at the base of the bladder, such as due to posterior urethral valves (in males) or bladder neck dysfunction.
  • Dysfunctional voiding: Poor bladder emptying habits or uncoordinated bladder muscle contractions.

Symptoms of Vesicoureteral Reflux

Many children with VUR, especially those with lower grades, may not have any noticeable symptoms. The condition is often diagnosed during investigations for recurrent UTIs. Symptoms that may suggest VUR or associated UTIs include:

• Frequent urinary tract infections (UTIs)
• Fever
• Pain in the side or back (flank pain)
• Painful urination (dysuria)
• Frequent or urgent need to urinate
• Bedwetting (enuresis), especially if it's new
• Poor growth or failure to thrive (in severe cases)

Diagnosis of Vesicoureteral Reflux

Several tests can be used to diagnose VUR:

• Voiding Cystourethrogram (VCUG): This is the primary diagnostic test for VUR. A catheter is placed into the bladder, and the bladder is filled with a contrast dye. X-ray images are taken while the bladder fills and while the child urinates, allowing doctors to see if urine is flowing backward into the ureters and kidneys. The VCUG can also help identify any structural abnormalities of the bladder and urethra.
• Radionuclide Cystogram (RNC): This test is similar to a VCUG but uses a radioactive tracer instead of contrast dye. It involves less radiation exposure and is often used for follow-up to monitor VUR.
• Renal Ultrasound: This imaging technique uses sound waves to create pictures of the kidneys and bladder. It can help identify kidney abnormalities, such as scarring or hydronephrosis (swelling of the kidney due to urine backup), but it cannot directly diagnose VUR.
• Dimercaptosuccinic Acid (DMSA) Scan: This nuclear medicine scan assesses kidney function and can detect kidney scarring (renal scarring) that may have resulted from recurrent UTIs associated with VUR.

Treatment of Vesicoureteral Reflux

The management of VUR depends on the grade of reflux, the child's age, the presence of symptoms (especially recurrent UTIs), and the presence of kidney damage. Treatment options include:

1. Observation and Prophylactic Antibiotics:

• For lower grades of VUR (I and II), especially in young children, the primary approach is often observation. Many children, particularly those with primary VUR, will outgrow the condition as they get older and their ureterovesical junction matures.
• Low-dose prophylactic (preventive) antibiotics may be prescribed daily to reduce the risk of UTIs while waiting for the VUR to resolve. The decision to use prophylactic antibiotics is made on an individual basis, considering the risk of UTIs and antibiotic resistance.

2. Surgical Correction:

Surgery may be recommended for higher grades of VUR (III, IV, and V), children with breakthrough UTIs despite antibiotic prophylaxis, or those with evidence of kidney damage. Surgical options include:

• Open Ureteral Reimplantation: This is a traditional surgical procedure where the ureter is detached from the bladder and re-implanted in a new position with a longer submucosal tunnel. This creates a more effective one-way valve mechanism to prevent reflux. This surgery has a high success rate.
• Laparoscopic Ureteral Reimplantation: This minimally invasive approach uses small incisions and a laparoscope to perform the ureteral reimplantation. It offers benefits such as smaller scars and faster recovery compared to open surgery.
• Endoscopic Injection (Deflux Injection): This minimally invasive procedure involves injecting a biocompatible bulking agent (such as dextranomer/hyaluronic acid copolymer) near the opening of the ureter in the bladder. This creates a bulge that narrows the opening and helps prevent reflux. Endoscopic injection is less invasive than open surgery but may have a lower success rate and may require repeat injections.

3. Management of Secondary VUR:

Treatment for secondary VUR focuses on addressing the underlying cause. This may involve managing neurogenic bladder with medications or catheterization, correcting bladder outlet obstruction surgically, or addressing dysfunctional voiding with behavioral therapies and biofeedback.

Long-Term Outlook

The long-term outlook for children with VUR is generally good, especially for those with lower grades who often outgrow the condition. Regular follow-up with a pediatric urologist or nephrologist is important to monitor the VUR, screen for UTIs, and assess kidney function. Early diagnosis and appropriate management can help minimize the risk of complications and protect kidney health.

If you or your child has been diagnosed with VUR or is experiencing symptoms suggestive of the condition, it's crucial to seek medical advice for proper evaluation and a personalized treatment plan.