Vesicoureteral Reflux (VUR)
A condition where urine flows backward from the bladder into the kidneys, potentially causing infections and kidney damage
Overview
Vesicoureteral reflux (VUR) is a urological condition in which urine flows retrograde, or backward, from the bladder through the ureters toward the kidneys. Under normal circumstances, urine flows in one direction—from the kidneys through the ureters and into the bladder, where a valve-like mechanism prevents backward flow. When this anti-reflux mechanism fails, urine can travel back up to the kidneys, potentially carrying bacteria and causing infections or kidney damage.
VUR is one of the most common urological anomalies in children, affecting approximately 1-2% of all children and up to 30-40% of children who experience urinary tract infections. While it can occur at any age, VUR is most frequently diagnosed in infancy and early childhood. The condition can be present from birth (primary VUR) or develop later due to bladder dysfunction or obstruction (secondary VUR).
The significance of VUR lies in its potential complications. When infected urine from the bladder reaches the kidneys, it can cause pyelonephritis (kidney infection), which may lead to renal scarring. Over time, repeated infections and scarring can result in hypertension, reduced kidney function, and in severe cases, chronic kidney disease. Early detection and appropriate management are crucial to prevent these long-term complications and preserve kidney function.
Common Symptoms
Vesicoureteral reflux itself often causes no symptoms and may only be discovered during evaluation for urinary tract infections or through prenatal ultrasound screening. However, when symptoms do occur, they are typically related to urinary tract infections:
Primary Symptoms
- Fever - Often the first sign of UTI in infants and young children
- Suprapubic pain - Discomfort or pain in the lower abdomen
- Involuntary urination - Bedwetting or daytime accidents in toilet-trained children
- Blood in urine - May be visible or detected only by urinalysis
Additional Signs in Children
- Strong, persistent urge to urinate
- Frequent urination in small amounts
- Burning sensation during urination
- Cloudy, strong-smelling urine
- Irritability in infants
- Poor feeding or failure to thrive
- Vomiting or diarrhea
- Lethargy or decreased activity
Signs of Kidney Involvement
When VUR leads to kidney infection (pyelonephritis), additional symptoms may include:
- High fever (often above 38.5°C or 101.3°F)
- Flank pain or back pain
- Nausea and vomiting
- General malaise and fatigue
- Chills and shaking
Causes and Risk Factors
Vesicoureteral reflux can be classified into two main types based on its underlying cause:
Primary VUR
Primary VUR is the most common form and results from a congenital abnormality in the vesicoureteral junction—where the ureter enters the bladder. Normally, the ureter tunnels through the bladder wall at an angle, creating a valve mechanism that prevents urine backflow. In primary VUR, this tunnel is too short or the angle is incorrect, allowing reflux to occur. This condition is often inherited, with approximately 30-50% of siblings and 65-85% of children of affected parents also having VUR.
Secondary VUR
Secondary VUR develops due to abnormally high bladder pressure or anatomical abnormalities that affect normal urine flow:
- Bladder outlet obstruction: Posterior urethral valves in boys
- Neurogenic bladder: Due to spina bifida or spinal cord injury
- Dysfunctional voiding: Poor coordination of bladder and sphincter muscles
- Chronic bladder inflammation: From recurrent infections
Risk Factors
- Age: Most common in infants and children under 2 years
- Gender: More common in girls overall, but more severe in boys when present
- Race: Higher prevalence in Caucasian children
- Family history: Strong genetic component with familial clustering
- Bladder dysfunction: Children with voiding disorders
- Anatomical abnormalities: Duplex collecting systems or ectopic ureters
- Prenatal hydronephrosis: Detected on ultrasound during pregnancy
Diagnosis
Diagnosing vesicoureteral reflux requires imaging studies to visualize urine flow and assess the severity of reflux. The diagnostic approach typically follows a stepwise pattern:
Initial Evaluation
- Medical history: Including UTI frequency, voiding patterns, and family history
- Physical examination: Checking for spinal abnormalities, abdominal masses
- Urinalysis and culture: To detect infection and identify causative organisms
- Blood tests: Kidney function tests (creatinine, BUN) if indicated
Imaging Studies
- Voiding Cystourethrogram (VCUG): The gold standard for diagnosing and grading VUR. Contrast material is inserted into the bladder through a catheter, and X-rays are taken during filling and voiding
- Radionuclide cystography (RNC): Uses radioactive material with less radiation exposure than VCUG
- Renal ultrasound: Evaluates kidney size, hydronephrosis, and scarring
- DMSA scan: Detects renal scarring and assesses differential kidney function
- Urodynamic studies: May be needed to evaluate bladder function
VUR Grading System
| Grade | Description |
|---|---|
| Grade I | Reflux into ureter only |
| Grade II | Reflux into ureter, pelvis, and calyces without dilation |
| Grade III | Mild to moderate dilation of ureter and renal pelvis |
| Grade IV | Moderate dilation with blunting of calyces |
| Grade V | Severe dilation and tortuosity of ureter with loss of papillary impressions |
Treatment Options
Treatment for vesicoureteral reflux depends on the grade of reflux, age of the patient, presence of bladder dysfunction, and history of UTIs. The main goals are to prevent kidney infections and preserve renal function:
Conservative Management
Many children with low-grade VUR (grades I-III) will outgrow the condition as they mature:
- Antibiotic prophylaxis: Daily low-dose antibiotics to prevent UTIs
- Regular monitoring: Periodic urine cultures and imaging studies
- Bladder training: Timed voiding and complete bladder emptying
- Treatment of constipation: Can worsen bladder dysfunction
- Good hygiene practices: Proper wiping technique and regular bathing
Surgical Intervention
Surgery may be recommended for high-grade reflux, breakthrough UTIs, or failure of conservative management:
Open Surgical Repair (Ureteral Reimplantation)
- Repositions the ureter to create a longer tunnel through bladder wall
- Success rate of 95-98%
- Requires hospitalization and recovery time
Endoscopic Treatment
- Injection of bulking agent (Deflux) at ureteral opening
- Minimally invasive outpatient procedure
- Success rate of 70-90% depending on grade
- May require repeat injections
Treatment of Bladder Dysfunction
- Anticholinergic medications: For overactive bladder
- Biofeedback therapy: To improve voiding coordination
- Clean intermittent catheterization: For incomplete bladder emptying
- Treatment of underlying conditions: Such as posterior urethral valves
Prevention and Management
While primary VUR cannot be prevented due to its congenital nature, several strategies can help prevent complications and manage the condition effectively:
UTI Prevention
- Maintain good hygiene: Proper perineal care, especially in girls
- Regular voiding: Every 2-3 hours during the day
- Complete bladder emptying: Double voiding if necessary
- Adequate hydration: Encourages frequent urination
- Prompt treatment of constipation: Reduces bladder pressure
- Avoid bubble baths: May irritate the urethra
- Cotton underwear: Allows better air circulation
Monitoring and Follow-up
- Regular urine cultures: Even without symptoms
- Periodic imaging: To assess reflux resolution or progression
- Blood pressure monitoring: To detect hypertension early
- Kidney function tests: Annual assessment in severe cases
- Growth monitoring: Chronic kidney disease can affect growth
Lifestyle Modifications
- Dietary considerations: Low-salt diet if hypertension develops
- Activity restrictions: Usually none unless recent surgery
- Education: Teaching children about proper bathroom habits
- Psychological support: For children with voiding dysfunction
When to See a Doctor
Prompt medical attention is essential for children with VUR to prevent kidney damage. Contact your healthcare provider in the following situations:
Seek immediate medical care if your child experiences:
- High fever (above 38.5°C or 101.3°F) with urinary symptoms
- Severe back or flank pain
- Persistent vomiting with fever
- Signs of dehydration (dry mouth, no tears, decreased urination)
- Blood in urine visible to the naked eye
- Extreme lethargy or confusion
Schedule an appointment for:
- Recurrent UTIs (two or more in six months)
- Persistent bedwetting in a previously dry child
- Frequent daytime wetting accidents
- Painful or difficult urination
- Foul-smelling or cloudy urine
- Poor weight gain or growth
- Family history of VUR in siblings
Note: Children with known VUR should have a clear action plan for managing fevers and potential UTIs. Always err on the side of caution and seek medical evaluation for unexplained fevers in children with VUR.
Related Conditions
Several conditions may occur alongside or be confused with vesicoureteral reflux:
- Urinary Tract Infection (UTI): The most common complication of VUR
- Hydronephrosis: Kidney swelling that may occur with or without VUR
- Posterior Urethral Valves: Congenital obstruction in boys causing secondary VUR
- Neurogenic Bladder: Bladder dysfunction from nerve problems
- Duplex Kidney: Congenital anomaly often associated with VUR
- Bladder Diverticula: Outpouchings that can cause reflux
- Megaureter: Abnormal ureteral dilation that may accompany VUR
- Dysfunctional Elimination Syndrome: Combined bladder and bowel dysfunction
- Renal Scarring: Permanent kidney damage from recurrent infections
- Chronic Kidney Disease: Long-term complication of severe VUR
Frequently Asked Questions
Will my child outgrow vesicoureteral reflux?
Many children with mild to moderate VUR (grades I-III) will outgrow the condition as they mature, typically by age 5-10. The likelihood of spontaneous resolution depends on the grade of reflux, age at diagnosis, and presence of bladder dysfunction. Higher grades are less likely to resolve without intervention.
Is VUR hereditary?
Yes, VUR has a strong genetic component. Siblings of affected children have a 27-50% chance of also having VUR, and children of parents with VUR have up to a 65% chance. Screening of siblings is often recommended, especially if they have had UTIs.
Can VUR be detected before birth?
Prenatal ultrasound may show hydronephrosis (kidney swelling), which can be associated with VUR. However, not all cases of prenatal hydronephrosis indicate VUR, and not all VUR cases show prenatal abnormalities. Postnatal evaluation is necessary for definitive diagnosis.
What are the long-term complications of untreated VUR?
Untreated VUR, especially with recurrent infections, can lead to renal scarring, hypertension, reduced kidney function, and in severe cases, end-stage renal disease requiring dialysis or transplantation. Early detection and appropriate management significantly reduce these risks.
Is surgery always necessary for VUR?
No, surgery is not always necessary. Many children with low-grade reflux can be managed conservatively with antibiotic prophylaxis and monitoring. Surgery is typically reserved for high-grade reflux, breakthrough infections despite antibiotics, or failure to outgrow the condition.
Can adults have vesicoureteral reflux?
While VUR is primarily diagnosed in children, adults can have VUR either as a continuation from childhood or developing secondary to bladder outlet obstruction, neurogenic bladder, or other conditions. Adult VUR requires evaluation and management to prevent kidney damage.