Vesicoureteric reflux: SAQ

This child has grade IV left vesicoureteric reflux with an established upper-pole cortical scar and a strong clinical picture of bladder and bowel dysfunction. The recurrent febrile infection, the high-grade reflux, the cortical defect on the DMSA scan, and the infrequent voiding with daytime urgency are all consistent with reflux nephropathy complicated by a dysfunctional bladder. The grade IV is defined by the moderate dilatation, the obliterated calyceal fornices, and the preserved papillary impressions. [1]

Question 1 (10 marks)

Describe the International Reflux Study grading system for vesicoureteric reflux and outline the management of this child, including the role of antimicrobial prophylaxis and the evidence that supports it. [3]

The International Reflux Study grading system, published by Lebowitz and colleagues, grades reflux from grade I to grade V on the micturating cystourethrogram. Grade I is reflux into a non-dilated ureter only. Grade II reaches the renal pelvis and calyces without dilatation and with preserved fornices. Grade III shows mild dilatation and tortuosity of the ureter with blunting of the calyceal fornices. Grade IV shows moderate dilatation and tortuosity with complete obliteration of the fornices but preservation of the papillary impressions. Grade V shows gross dilatation with loss of all papillary impressions. [1]

The management of this child follows the American Urological Association guideline framework. She has high-grade reflux with recurrent febrile infection and an established scar, so she needs continuous antibiotic prophylaxis as the first step. The first-line agent is trimethoprim at 2 mg per kg at night, with nitrofurantoin at 1 mg per kg at night as an alternative. The prophylaxis is continued until the reflux resolves, is corrected, or the child is old enough that the risk of new scarring is low. [3]

The evidence for prophylaxis comes from the RIVUR trial, the Randomized Intervention for Children with Vesicoureteral Reflux, published in the New England Journal of Medicine in 2014 by the RIVUR Trial Investigators led by Hoberman. The trial randomised 607 children aged 2 to 71 months with grade I to IV reflux after one or two febrile infections to trimethoprim-sulfamethoxazole or placebo. It found that 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, which was approximately 11 percent in both groups. [2]

If this child has a breakthrough febrile infection despite the prophylaxis, the next step is endoscopic injection of dextranomer and hyaluronic acid copolymer, known as Deflux, which has a success rate of approximately 70 to 80 percent per injection for the lower grades. For the high-grade reflux or a failed endoscopic correction, the definitive option is open ureteric reimplantation, which has a success rate of 95 to 98 percent and is the most durable single procedure. [3]

Question 2 (10 marks)

Discuss the role of bladder and bowel dysfunction in this child and how it modifies the management and the prognosis. [5]

This child has clinical features of bladder and bowel dysfunction, including the daytime urgency and the infrequent voiding of only three times a day. Bladder and bowel dysfunction is the strongest modifier of the reflux outcome, and Elder and Diaz showed that it is present in over 40 percent of children with reflux. It reduces the spontaneous resolution rate by half, doubles the risk of breakthrough febrile infection, and halves the success rate of endoscopic injection. [5]

The management of this child must begin with the treatment of the bladder and bowel dysfunction, before any surgical correction of the reflux is considered. The first intervention is timed voiding, in which the child is encouraged to void every 2 to 3 hours by a watch or a reminder, to overcome the infrequent voiding pattern. The constipation is assessed and treated with laxatives and a high-fibre diet, because the loaded rectum compresses the bladder and worsens the voiding dysfunction. An anticholinergic medication such as oxybutynin may be added for the overactive bladder with the urgency, and biofeedback is used in the older child to teach the coordinated relaxation of the pelvic floor during voiding. [5]

The bladder and bowel dysfunction modifies the prognosis. The child with both reflux and bladder and bowel dysfunction has a lower rate of spontaneous resolution, a higher rate of breakthrough infection, and a higher risk of progressive renal scarring. The DMSA scan has already shown a cortical defect at the upper pole of the left kidney, which is an established scar that will not resolve. The scar carries a life-long risk of hypertension, so the blood pressure must be monitored at every visit. [8]

The long-term prognosis is determined by the renal scarring, not by the reflux grade itself. The child with scarring carries the risk of hypertension, proteinuria, and chronic kidney disease into adulthood, and the adolescent girl with reflux nephropathy has an additional risk of pre-eclampsia in pregnancy. The surveillance includes the annual blood pressure, the annual urinalysis for proteinuria, and the periodic serum creatinine. The transition to adult nephrology care is planned in adolescence, because the reflux nephropathy persists and the risk of chronic kidney disease continues into adulthood. [8]