Vesicoureteric Reflux
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Direct answer
Vesicoureteric reflux is retrograde flow of urine from the bladder into the ureter during voiding, graded I to V on micturating cystourethrogram (MCU). It predisposes to urinary tract infection and renal scarring, and lower-grade reflux often resolves spontaneously. Management balances continuous antibiotic prophylaxis against endoscopic injection or ureteric reimplantation, guided by the grade, breakthrough infection and scarring on DMSA scan.
What you must remember
- International grading: grade I reflux into the ureter only; grade II into pelvis and calyces without dilatation; grade III mild to moderate dilatation with minimal fornix blunting; grade IV moderate dilatation with obliterated fornices but papillary impressions still visible in most calyces; grade V gross dilatation, a tortuous ureter and loss of papillary impressions.
- Gold standard: MCU for grading reflux; DMSA renal scan detects cortical scarring.
- Spontaneous resolution: more likely with grades I to III and in younger children; grades IV and V rarely resolve.
- Renal scarring: the greatest risk comes from breakthrough febrile infection in high-grade reflux.
- Prophylaxis: continuous low-dose antibiotic such as trimethoprim-sulphamethoxazole, nitrofurantoin or cephalexin; RIVUR showed fewer recurrent UTIs but no reduction in scarring.
- Surgical indications: breakthrough UTI on prophylaxis, poor compliance, progressive scarring or high-grade reflux with bladder dysfunction.
- Family screening: siblings and offspring are commonly screened, because reflux is familial.
- Surgical options: subureteric endoscopic injection or open or laparoscopic ureteric reimplantation.
A graded pathway from first UTI to decision
A 2-year-old girl has a culture-proven febrile UTI and a first renal ultrasound that shows mild pelvic dilatation. The pathway below defines grade, scarring and treatment before any decision on surgery.
- Confirm the infection. Culture-proven UTI is the trigger for imaging, especially in young children with fever.
- Image the kidneys and bladder. Renal ultrasound first, then MCU to grade reflux.
- Assess scarring. DMSA scan at the acute stage or later, to identify cortical defects.
- Start prophylaxis. Moderate to high grade reflux is covered with continuous low-dose antibiotic while the decision is made.
- Repeat imaging selectively. Re-image to check resolution, rather than at fixed short intervals.
- Decide on surgery. Consider endoscopic injection or reimplantation for breakthrough infection, poor adherence or progressive scarring.
Where the exam tries to catch you
Reflux questions often test grading, the role of DMSA and the evidence on prophylaxis.
- Trap: choosing surgery as the default because reflux is present. Correct: lower-grade reflux usually resolves, and surgery is reserved for breakthrough infection, non-adherence or progressive scarring.
- Trap: grading reflux from an ultrasound. Correct: ultrasound shows hydronephrosis, but grading requires contrast MCU.
- Trap: stopping prophylaxis after one clean culture. Correct: prophylaxis continues until reflux resolves or surgery is performed.
- Trap: assuming prophylaxis prevents scarring entirely. Correct: RIVUR showed fewer recurrent UTIs, but it did not show less scarring, so early treatment of infection still matters.
Frequently asked questions
Which imaging test grades vesicoureteric reflux in children?
The micturating cystourethrogram grades vesicoureteric reflux in children using the five-grade international system. It is performed with contrast during voiding, and it is more accurate than ultrasound for detecting and grading reflux.
Which investigation detects renal scarring in vesicoureteric reflux?
A DMSA renal scan detects renal scarring in vesicoureteric reflux, showing cortical defects. It is the most sensitive test for scarring, which is why it is used alongside MCU in children with reflux.
Which antibiotic prophylaxis is commonly used for vesicoureteric reflux in children?
Trimethoprim-sulphamethoxazole, nitrofurantoin and cephalexin are commonly used as continuous low-dose prophylaxis for vesicoureteric reflux in children. The choice depends on age, local resistance patterns and the child's tolerance of the drug.
What did the RIVUR trial show about prophylaxis in vesicoureteric reflux?
The RIVUR trial showed that continuous antibiotic prophylaxis reduced recurrent urinary tract infection in children with vesicoureteric reflux. It did not show a reduction in renal scarring, so the value of prophylaxis lies mainly in preventing breakthrough infection.
Which grade of vesicoureteric reflux is most likely to resolve spontaneously?
Lower grades, particularly grades I to III, are most likely to resolve spontaneously in vesicoureteric reflux. Grades IV and V rarely resolve, which is why they are more often managed with prophylaxis and considered for surgery.