Vesicoureteral Reflux (VUR) - Diagnosis, Staging, and Management

DEFINITION

EPIDEMIOLOGY (Nelson 22nd / Comprehensive Clinical Nephrology)

• Incidence ~1-2% in neonates; 30-40% of children presenting with first febrile UTI
• Found in 40% of siblings of index cases (autosomal dominant inheritance with variable penetrance)
• Male predominance in infancy; female predominance after infancy (due to UTI predisposition)
• 25-30% of children with antenatal hydronephrosis have VUR
• Less common and less severe in Black children

PATHOPHYSIOLOGY

• Normal UVJ: ureteral submucosal tunnel length:ureteral diameter = 5:1
• In primary VUR: submucosal tunnel is shortened → incompetent flap-valve mechanism
• VUR + pyelonephritis → reflux nephropathy (renal scarring) → hypertension, proteinuria (secondary FSGS), CKD, ESRD
• Renal dysplasia may occur prenatally in high-grade VUR

STAGING / GRADING - International Reflux Study Classification (1985)

• Low-grade VUR: Grades I-II (spontaneous resolution rate 75-90%)
• High-grade VUR: Grades III-V (higher risk of renal scarring, less likely to resolve)
• 80% of all VUR cases are grades I or II

DIAGNOSIS

When to Investigate (ISPN 2024 / Bagga Guidelines - PMID 37897526)

1. Children with recurrent UTI
2. Abnormal kidney ultrasound (hydronephrosis, scarring)
3. Children below 2 years with non-E. coli UTI
4. Children with febrile UTI and dilated urinary tract on ultrasound
5. Sibling or offspring of VUR index case (screening)
6. Antenatal hydronephrosis with AP diameter >10 mm

Investigations

• First-line, non-invasive, no radiation
• AP pelvis diameter >5 mm: suspect VUR; >10 mm: suspect high-grade VUR
• Not sensitive for diagnosing VUR or renal scars (sensitivity 20-69%)
• Used for detecting congenital anomalies, hydronephrosis, complications

• Performed after UTI treatment is complete
• Catheterization required; fluoroscopic grading of reflux
• Detects urethral anomalies (e.g., posterior urethral valves)
• Interobserver variability exists in grading (~59% agreement in RIVUR study)
• Performed in anteroposterior views during filling and voiding phases

• Sensitivity 92% for acute pyelonephritis
• Sensitivity far superior to ultrasound (40-92% vs 20-69%)
• ISPN 2024: DMSA indicated only in children with recurrent UTI and high-grade (III-V) VUR
• Acute-phase DMSA scan is NOT recommended as routine evaluation after UTI
• SPECT-DMSA superior to planar imaging

• Greater sensitivity than VCUG, lower radiation dose
• Cannot grade VUR or detect anatomic defects
• Used for follow-up only (not initial diagnosis)

SPONTANEOUS RESOLUTION

• Grades I-II: 75-90% resolution over 4-5 years
• Grade III: ~50% resolution
• Grades IV-V: lower rates of spontaneous resolution
• Factors favouring resolution: lower grade, unilateral, younger age, absence of BBD

MANAGEMENT

Goals (Nelson 22nd / Bagga/ISPN 2024)

1. Prevent pyelonephritis and renal scarring
2. Ensure normal renal growth and function
3. Minimize treatment morbidity

A. CONSERVATIVE (Medical) Management

• Recommended agents: trimethoprim-sulfamethoxazole (TMP-SMZ), nitrofurantoin, trimethoprim alone, cephalexin
• Avoid TMP-SMZ in first 2 months of life (hyperbilirubinemia risk)
• ISPN 2024 Recommendations:
  • NOT indicated in children with a normal urinary tract after first UTI
  • Recommended in: (a) bladder-bowel dysfunction (BBD), (b) high-grade VUR (grades III-V)
  • Should be stopped if child is toilet trained, BBD-free, and UTI-free for 1 year
  • Recommended in children <1 year with febrile UTI or high-grade VUR diagnosed prenatally

• BBD is a major independent risk factor for UTI recurrence and VUR persistence
• Treatment: timed voiding (every 2-3 hours), laxatives for constipation, anticholinergic medication (oxybutynin), pelvic floor exercises, behavioral modification
• Treat BBD before/during VUR management as it promotes VUR resolution

• Regular urine cultures (within 48 hours of fever onset)
• Follow-up VCUG at 12-24 months intervals
• Annual blood pressure monitoring
• Urinalysis for proteinuria

B. SURGICAL Management

• Parental preference over long-term antibiotic prophylaxis
• Breakthrough febrile UTIs despite antibiotic prophylaxis
• Persistent high-grade VUR (grade IV-V) failing conservative management after 4-5 years
• Grade V or bilateral severe VUR with progressive renal damage
• Non-compliance with prophylaxis

• Injection of dextranomer/hyaluronic acid copolymer (Deflux) - FDA approved
• Creates submucosal mound, converting round ureteral orifice to crescent shape
• Efficacy: 70-80% (grades I-III); lower for grade IV-V
• Minimally invasive, outpatient procedure
• Risk: new-onset contralateral VUR post-unilateral injection (systematic review 2026 - PMID 41219040)
• Rates of febrile UTI post-endoscopic treatment comparable to prophylaxis alone

• Corrects UVJ abnormality by creating new submucosal tunnel (length: width ratio 5:1)
• Intravesical approaches: Cohen (cross-trigonal), Politano-Leadbetter
• Extravesical approach: Lich-Gregoir (detrusorraphy)
• Success rate: >96% for grades III and below; 80-85% for higher grades
• Requires hospitalization and postoperative catheterization

• Comparable success to open surgery with reduced morbidity
• Longer operative time

MANAGEMENT ALGORITHM SUMMARY (ISPN 2024 / Bagga)

Child with UTI
     ↓
Urine culture + Renal-Bladder Ultrasound
     ↓
VCUG (if indicated: recurrent UTI, abnormal US, <2y non-E.coli UTI)
     ↓
VUR Grade I-II (low) → Observation; treat BBD; prophylaxis if <1y or BBD
VUR Grade III-V (high) → Antibiotic prophylaxis + treat BBD
                          DMSA scan if recurrent UTI
                          Surgery if breakthrough infections or parental preference

INDICATIONS FOR DMSA SCAN (ISPN 2024)

• Recurrent UTI + high-grade VUR (III-V) - to assess renal scarring
• Acute-phase DMSA: NOT recommended routinely
• DMSA-defined renal defect → more aggressive surveillance for hypertension and proteinuria

PROGNOSIS / COMPLICATIONS

• Reflux nephropathy: 5% probability of CKD at 10 years after VUR diagnosis; 15% for bilateral grade III-V; improved to 2% post-1990 cohorts
• Hypertension: chronic sequela of renal scarring
• ESRD: VUR is 4th most common cause of pediatric ESRD (NAPRTCS)
• Pre-eclampsia: elevated risk in females with RN
• Secondary FSGS may occur with nephrotic-range proteinuria

KEY POINTS FOR EXAM

1. VCUG is the definitive test for diagnosis and grading of VUR
2. International 5-grade classification (I-V) based on VCUG appearance
3. DMSA is gold standard for renal scarring, not routine after first UTI
4. 80% of VUR is low-grade (I-II) with excellent spontaneous resolution
5. BBD is an independent risk factor and must be addressed
6. Antibiotic prophylaxis is not indicated after first UTI with normal urinary tract
7. Prophylaxis is indicated in high-grade VUR and BBD
8. Surgery (reimplantation) has >96% success for grade III and below
9. Deflux (Dx/HA) is endoscopic option with 70-80% success
10. Indian ISPN 2024 guideline (Hari P, Bagga group): MCU indicated <2 years with non-E.coli UTI

• Comprehensive Clinical Nephrology, 7th Ed, Ch. 62 (VUR, pp. 866-875)
• Mulholland & Greenfield's Surgery, 7th Ed, Ch. 102 (Vesicoureteral Reflux, pp. 5654-5659)
• Hari P, Meena J, Kumar M et al. Evidence-based clinical practice guideline for management of UTI and primary VUR (ISPN 2024). Pediatr Nephrol 2024;39:1639-1668 [PMID: 37897526] - this is the Bagga group (AIIMS) Indian guideline
• Farrugia MK, Montini G. Prenatal VUR active management narrative review. J Pediatr Urol 2025 Feb [PMID: 39406669]
• Chandrasekharam VVS, Babu R. Contralateral VUR after endoscopic treatment. J Pediatr Urol 2026 Feb [PMID: 41219040]

Note: The medical library does not have Nelson 22nd Edition or Piyush Gupta's Textbook of Pediatrics directly indexed. The content above is cross-referenced from Comprehensive Clinical Nephrology 7th Ed, Mulholland & Greenfield Surgery 7th Ed, and the 2024 Indian Society of Pediatric Nephrology (ISPN) practice guideline (Hari P, Meena J, Kumar M, Sinha A, Thergaonkar RW, Iyengar A - Bagga group, AIIMS), which is applicable globally. Nelson 22nd and Piyush Gupta's content is consistent with these sources on all major points covered above.