Vesicoureteral reflux
Know in whom to look for VUR, assign the risk group, and decide which children need prophylaxis and which need surgery.
Step 1 of 10
Objectives
After this topic you will be able to
- Distinguish primary from secondary VUR.
- Grade VUR on VCUG.
- Know the indications for VCUG under the EAU and AAP 2026 guidelines.
- Apply the AAP 2026 risk groups and the indications for antibiotic prophylaxis.
- Know the indications for surgery and the principles of long-term follow-up.
- Take into account the role of bladder and bowel dysfunction.
The main goal in managing VUR is to prevent febrile UTI and new renal damage. Decisions are therefore based not on the grade of reflux alone, but on the grade together with BBD, renal scarring and the history of infections.
Basics
Vesicoureteral reflux (VUR)
VUR is the backflow of urine from the bladder into the ureter and kidney. Primary VUR is related to immaturity of the valve mechanism where the ureter enters the bladder and often resolves with age. Secondary VUR results from conditions that raise bladder pressure, such as obstruction (posterior urethral valves, PUV) or neurogenic bladder.
- 1–2% of the general pediatric population
- 30–50% of children with UTI (depending on age)
- ~30% of siblings of a child with VUR
Basics
VUR grades
| Grade | Appearance on VCUG (voiding cystourethrogram) |
|---|---|
| I | Contrast reaches the ureter only |
| II | Ureter, pelvis and calyces fill, no dilation |
| III | Mild to moderate dilation of the ureter and pelvis, slight blunting of the fornices |
| IV | Moderate dilation, tortuous ureter, blunted fornices, papillary impressions preserved |
| V | Severe dilation and tortuosity, papillary impressions lost |
Grade I–III reflux resolves on its own within a few years in most children; grade III resolves less often than grades I–II. High grade, bilateral reflux and BBD reduce the likelihood of resolution.
Diagnosis
How is VUR detected?
- VCUG (voiding cystourethrogram) is the main study for diagnosing and grading VUR; it also shows urethral and bladder anomalies. The alternative is contrast-enhanced voiding urosonography (no radiation). It is not done during acute infection.
- Ultrasound does not reliably detect VUR: in the AAP 2026 analysis, its sensitivity was about 50% after a first febrile UTI and about 26% after recurrent UTI. A normal ultrasound does not exclude VUR, but it makes high-grade VUR less likely.
- DMSA: shows renal scarring; it is done at least 6 months after the infection (EAU, weak). Scarring is the key risk marker in managing VUR.
Diagnosis
Who needs a VCUG?
- EAU 2026 (weak): a first febrile UTI before 12 months of age (with a typical infection and a normal ultrasound, waiting for a second infection is also reasonable); recurrent febrile UTI, an abnormal ultrasound or an abnormal DMSA; atypical UTI at any age.
- AAP 2026 (conditional): routine VCUG is not recommended after a first febrile UTI with a normal ultrasound. VCUG is offered for: a clinically significant abnormality on ultrasound, a second febrile UTI in a child younger than 2 years, or a second febrile UTI with no other explanation in a child older than 2 years.
- The "top-down" approach: renal damage is first assessed with DMSA, and VCUG is done only if the DMSA is abnormal. The choice is made together with a pediatric urologist based on age, risk and local resources.
A detailed comparison of the imaging algorithms after UTI is given in the "Urinary tract infection" module.
Treatment
AAP 2026: risk groups in VUR
For primary care clinicians, AAP 2026 divides VUR into low-risk and high-risk groups, with grade III VUR treated as an indeterminate group. This classification is offered as an initial approach until the child is seen by a pediatric urologist; the urologist and nephrologist members of the panel did not fully support it.
| Risk group | Criteria | Prophylaxis (AAP 2026) |
|---|---|---|
| Low risk | Grade I–II VUR and no BBD (in this definition, functional constipation by Rome criteria is not counted as BBD) | Routine prophylaxis is not recommended (conditional, low certainty of evidence) |
| Indeterminate | Grade III VUR | Prophylaxis is a reasonable option if the family values a lower risk of infection more than avoiding antibiotics |
| High risk | Grade IV–V VUR; intrarenal reflux; renal scarring or nephropathy; structural anomaly of the kidney or ureter, cortical abnormality of the kidney; recurrent pyelonephritis; bacteremia leading to intensive care admission; BBD (functional constipation not included) | Prophylaxis is considered as an option; the child is referred to a pediatric urologist or pediatric nephrologist |
- All decisions about prophylaxis are shared with the family (good practice statement).
- Management of VUR includes observation, prophylaxis, endoscopic injection and ureteral reimplantation; the choice is made together with a pediatric urologist or pediatric nephrologist.
- Where direct access to a pediatric urologist is limited, an online consultation can also be used.
Compared with the EAU: the EAU makes a strong recommendation to offer prophylaxis to children at risk of recurrent UTI, whereas the AAP emphasizes avoiding routine prophylaxis in low-risk VUR. In both approaches, BBD is a key risk factor.
Treatment
Antibiotic prophylaxis
Offered to children at risk of recurrent UTI (EAU 2026, strong). It is given once daily at bedtime, at about one quarter of the treatment dose. In large randomized trials (RIVUR, PREDICT), prophylaxis reduced the risk of recurrent UTI but increased the risk of resistant bacteria. After a first or second UTI in a child with a normal urinary tract, prophylaxis has not been shown to reduce new renal damage.
- The greatest benefit is seen in infants with grade III–V VUR, children with BBD and children with recurrent febrile UTI.
- Megaureter: prophylaxis is recommended in the first year of life; a ureteral diameter of 7 mm or more carries a higher risk of UTI.
- In older children with low-grade VUR and normal bladder function, follow-up without prophylaxis is acceptable.
- BBD must be treated during prophylaxis; if constipation persists, prophylaxis is less effective.
| Drug | Note |
|---|---|
| Nitrofurantoin | First choice; not given to infants younger than 2 months |
| Trimethoprim (2 mg/kg) | First choice; not given to infants younger than 6 weeks |
| Cefaclor, cefixime | In exceptional cases, for example in young infants |
Non-antibiotic measures: cranberry products reduce recurrence (moderate evidence); probiotics can be used only as an adjunct; vitamins are not used routinely. In boys with phimosis and UTI, topical steroid cream reduces recurrence; circumcision is of greater benefit in boys who also have PUV or VUR.
Treatment
Indications for surgery in VUR
- Recurrent febrile UTI despite prophylaxis (breakthrough infection).
- New scars on DMSA.
- High-grade, persistent reflux that is unlikely to resolve with age.
- The family does not want, or is unable to follow, long-term prophylaxis.
| Method | Characteristics |
|---|---|
| Endoscopic injection | Short anesthesia, no incision, day surgery; success about 50–80% depending on grade |
| Ureteral reimplantation (open or robot-assisted) | Open surgery: success about 92–98%; robot-assisted results vary more widely and on average are poorer than those of open surgery. A larger operation than endoscopic treatment |
Treatment
Long-term follow-up
- In children with renal scarring, blood pressure and proteinuria are checked regularly.
- Urinalysis with every fever: the family is told when and how to seek care.
- BBD: screen for and treat bladder and bowel dysfunction in every toilet-trained child with febrile and/or recurrent UTI (EAU 2026, strong); ask about constipation and voiding habits at every visit. Treating constipation lowers recurrence.
- Girls with VUR are informed about the risk of UTI in future pregnancy.
The pediatrician's role: urinalysis with every fever in a child with VUR, treatment of BBD, assignment of the risk group, and referral of high-risk children to a pediatric urologist.
Quiz
Quiz: Vesicoureteral reflux
Test yourself: choose one answer.
A 2-year-old girl has unilateral grade II VUR on VCUG, no BBD and no scarring on DMSA. What is the most appropriate approach under AAP 2026?
Grade I–II VUR without BBD falls into the AAP 2026 low-risk group, in which routine prophylaxis is not recommended. The decision is shared with the family.
A child with a febrile UTI has a normal ultrasound. What can be said about VUR?
After a first febrile UTI, the sensitivity of ultrasound for VUR is about 50%. A normal ultrasound does not exclude VUR, but it makes high-grade VUR less likely. VUR is detected by VCUG or contrast-enhanced voiding urosonography.
On VCUG, the ureter and pelvis are moderately dilated, the ureter is tortuous, and papillary impressions are preserved. What is the VUR grade?
Moderate dilation, a tortuous ureter and preserved papillary impressions are characteristic of grade IV. In grade V the papillary impressions are lost.
A child with VUR has recurrent febrile UTIs while on prophylaxis. Which factor should be checked first?
BBD (especially constipation) is one of the most important causes of breakthrough infections and should be treated before a decision on surgery.
Related topics
Related articles for parents
Sources
- Alverson BK, Hains DS, Downs SM, et al. Clinical practice guideline for the diagnosis and treatment of urinary tract infection in children from 8 days to 5 years of age. Pediatrics. 2026;158(4):e2026078565.
- EAU Guidelines on Paediatric Urology, 2026: Vesicoureteric reflux; Urinary tract infections in children.
- RIVUR Trial Investigators. Antimicrobial prophylaxis for children with vesicoureteral reflux. N Engl J Med. 2014;370(25):2367–2376.
- Morello W, Baskin E, Jankauskiene A, et al. Antibiotic prophylaxis in infants with grade III, IV, or V vesicoureteral reflux. N Engl J Med. 2023;389(11):987–997.
This material is intended for medical professionals and is based on current clinical guidelines. Decisions about an individual patient are made by the treating doctor.
Updated: