Vesicoureteric reflux: Viva

Branch 1: Grading and natural history

The candidate should define vesicoureteric reflux as the retrograde flow of urine from the bladder into the ureter and renal pelvis through an incompetent ureterovesical junction. A strong candidate grades this child as grade III on the micturating cystourethrogram, describing the International Reflux Study system from grade I to grade V: grade I is reflux into the ureter only, grade II reaches the pelvis and calyces without dilatation, grade III shows mild dilatation and tortuosity with blunting of the fornices, grade IV shows moderate dilatation with obliterated fornices but preserved papillary impressions, and grade V shows gross dilatation with loss of all papillary impressions. [1]

If the examiner presses on the natural history, the candidate should state that the spontaneous resolution rate is proportional to the grade. Low-grade reflux, grades I to II, resolves in up to 80 percent of children over 5 years, and grade III resolves in approximately 50 percent. The resolution occurs because the intramural tunnel lengthens as the bladder grows, which is the anatomical basis of the natural history. The high-grade reflux, grades IV to V, has a much lower resolution rate and is more likely to require surgical correction. [1]

Branch 2: The RIVUR trial and prophylaxis

If the examiner asks about the evidence for prophylaxis, the candidate should describe the RIVUR trial in detail. The Randomized Intervention for Children with Vesicoureteral Reflux trial, published in the New England Journal of Medicine in 2014 by the RIVUR Trial Investigators led by Hoberman, randomised 607 children aged 2 to 71 months with grade I to IV reflux after one or two febrile infections to trimethoprim-sulfamethoxazole prophylaxis or placebo. [2]

A strong candidate cites the two key findings: prophylaxis halved the rate of recurrent febrile or symptomatic infection from 23 percent in the placebo group to 13 percent in the prophylaxis group, but it did not reduce the rate of new renal scarring at two years, which was approximately 11 percent in both groups. The candidate should also mention the trade-off of increased trimethoprim-sulfamethoxazole-resistant Escherichia coli in the prophylaxis group, and the implication that the children who benefit most are those with the highest baseline risk, including those with reflux and bladder and bowel dysfunction. [2]

The first-line prophylactic agent is trimethoprim at 2 mg per kg at night, with nitrofurantoin at 1 mg per kg at night as an alternative for children over 3 months. The prophylaxis is started after the first febrile infection in a child with confirmed reflux, and it is continued until the reflux resolves, is corrected, or the child is old enough that the risk of new scarring is low. [3]

Branch 3: The management ladder and surgery

If the examiner moves to the management ladder, the candidate should describe the four steps. The first step is observation and surveillance for the child with low-grade reflux and no recurrent infection. The second step is continuous antibiotic prophylaxis for the child with reflux and a febrile infection, which is where this child belongs given his two febrile infections and bilateral grade III reflux. [3]

A strong candidate describes the two surgical options. Endoscopic injection of dextranomer and hyaluronic acid copolymer, known as Deflux, is placed beneath the ureteric orifice to augment the intramural tunnel. Kirsch and colleagues reviewed the 20-year experience, showing success rates of approximately 70 to 80 percent per injection for grades I to III and lower for the higher grades, with the option of repeat injection. Open ureteric reimplantation, using the Cohen transtrigonal or the Politano-Leadbetter technique, creates a new and longer intramural tunnel and has a success rate of 95 to 98 percent, making it the most durable single procedure. [7]

The candidate should then address the role of bladder and bowel dysfunction, which is the strongest modifier of the reflux outcome. Elder and Diaz showed that bladder and bowel dysfunction is present in over 40 percent of children with reflux, halves the spontaneous resolution rate, doubles the breakthrough infection rate, and halves the surgical success rate. The management prioritises the treatment of the bladder and bowel dysfunction, using timed voiding, constipation management, and anticholinergic medication, before any surgical correction is considered. [5]