VUR is fundamentally classified into two types: primary and secondary. The causes differ for each:

Primary VUR

• Congenital developmental defect: The valve mechanism at the ureterovesical junction is underdeveloped, allowing urine to flow back into the kidney. This is the most common form of VUR.

Secondary VUR

• Incomplete bladder emptying: Residual urine increases bladder pressure over time and can push urine back up the ureter.
• Urinary tract obstructions: Narrowings or blockages in the ureter or urethra impede normal flow, causing reflux.
• Neurogenic bladder: Neurological conditions such as spina bifida impair normal bladder muscle function, predisposing to VUR.
• Reflux following infections: Repeated UTIs can damage the urinary tract lining, leading to reflux.
• Constipation: Chronic constipation increases pelvic pressure and hinders bladder emptying, raising the risk of reflux.
• Pelvic floor dysfunction: Overly tense pelvic floor muscles can trap urine in the bladder, which under pressure may reflux to the kidneys.

VUR is a relatively common urological finding in childhood. Its prevalence in healthy children is around 1%, but this increases to 30–50% in those with recurrent urinary tract infections. Overall, girls have a higher incidence than boys, though in the neonatal period male infants are more frequently affected.

Some children with VUR are asymptomatic, while others present with recurrent urinary tract infections. In infants and toddlers, symptoms may be subtle.

Common symptoms in children:

• Recurrent urinary tract infections (UTIs)
• Burning or pain on urination
• Frequent urination or incontinence
• Unexplained fever (>38 °C)
• Foul-smelling or cloudy urine
• Blood in the urine (hematuria)
• Abdominal, flank, or back pain

In infants, there may also be:

• Irritability or poor feeding
• Failure to thrive
• Unexplained high fever
• Persistent diaper wetness

In older children:

• Daytime or nighttime bedwetting
• Sensation of incomplete bladder emptying
• Repeated urge soon after voiding
• Pain or tenderness over the kidneys

To confirm VUR, clinicians may recommend several investigations:

• Urinalysis: Screens for urinary tract infections, which often accompany VUR.
• Renal and bladder ultrasound: Noninvasive imaging to assess anatomy and detect hydronephrosis or structural abnormalities.
• Voiding cystourethrogram (VCUG): A contrast X-ray study performed during filling and voiding to directly visualize reflux. It is the gold standard for diagnosing VUR.
• DMSA renal scan: A nuclear medicine test to detect renal scarring from recurrent infections and assess functional loss.

Treatment depends on the child’s age, reflux grade, infection history, and renal involvement. The goals are to protect kidney function and prevent recurrent UTIs.

Observation:

• Many children with low-grade VUR outgrow the condition spontaneously.
• They undergo regular follow-up with ultrasound, urinalysis, and repeat VCUG if needed.

Antibiotic prophylaxis:

• Given in younger children or those at high risk of infection to prevent UTIs.
• Often administered as a single nightly dose.

Behavioral and functional support:

• Bladder training, adequate hydration, proper toileting habits, and management of constipation.
• Pelvic floor rehabilitation may be added if there is dysfunctional voiding.

Surgery:

• Reserved for high-grade reflux, associated renal scarring, or persistent infections despite medical management.

Untreated VUR can lead to repeated kidney infections and irreversible renal damage.

Possible complications include:

• Recurrent UTIs: Frequent infections that may ascend to the kidneys.
• Pyelonephritis: Severe kidney infections with fever and potential systemic effects.
• Renal scarring: Permanent damage that decreases kidney function and may cause hypertension.
• Hypertension: Results from renal scarring and may present later in life.
• Renal failure: Rare but possible in severe bilateral reflux.
• Growth impairment: Chronic infections and fevers can affect overall development.