Reflux is the abnormal passage of urine back up the ureter and may occur on one or both sides. It is managed by the pediatric urologist primarily. Reflux may be primary or secondary and its importance lies in the fact that when it is associated with a urinary tract infection (UTI) there is potential for pyelonephritis and renal scarring. The scarring may lead to hypertension, proteinuria and possible renal failure (reflux nephropathy).
Sterile reflux usually does not cause kidney damage, but high-grade sterile reflux may contribute.
Reflux probably occurs in 1% of the pediatric population. A symptomatic UTI will occur in about 3% of females and 1% of male children by 11 years of age. Radiologic studies of symptomatic or asymptomatic UTIs reveal reflux in 30% to 50% of children and in 40% to 60% of neonates with a UTI.
30% to 50% of children with reflux will have renal scarring on studies, and the scarring is more likely to occur in infants before the age of 2 years.
32% of siblings have reflux, though the majority are asymptomatic.
MECHANISM OF SCARRING
Research has shown that 3 conditions are necessary to produce renal scarring.
- Bacterial infection
- Intrarenal reflux
Fused or compound papillae contain papillary ducts with gaping orifices that allow intrarenal reflux, and these are found commonly in the polar areas of the kidney where scarring is found, especially the upper pole.
Kidneys already damaged at the time of initial examination are at greater risk of progression of scarring but this is almost always associated with recurrent urinary tract infections.
Scarring can take as long as six months from the time of the acute urinary tract infection to evolve.
Scarring may be accentuated by hypertrophy of adjacent parenchyma.
This begins after the first bona fide UTI. All children with a fever need to have a urine specimen evaluated. Workup for a UTI includes a voiding cystourethrogram (VCUG) with fluoroscopic monitoring and a renal sonogram.
Nuclear cystograms are useful for follow-up studies.
DMSA scanning is the most accurate investigation to document inflammation and scars.
Five grades of reflux are noted, with Grade 1 showing mild reflux in the ureter only and Grade 5 being severe, with distention and tortuosity of the ureter and calyces.
Cystoscopy is rarely indicated except where reflux may be secondary to an obstructive problem.
THERAPEUTIC GOALS IN MANAGEMENT OF REFLUX
- Treatment of any associated voiding dysfunction
- Prevention of pyelonephritis
- Prevention of scarring
- Promotion of normal renal growth
Treatment plans are individualized according to age/sex, grade of reflux, associated urologic problems, presence of scarring, hypertension, proteinuria, and patient/parent compliance.
In general, all children with reflux are treated initially with surveillance and prophylactic antibiotics, as in many the reflux will resolve spontaneously without the need for surgery. Children with urge incontinence will also need to take bladder antispasmodics.
All grades are initially handled non-surgically with monitoring of fluid intake, voiding/toilet habit and bowel habit, regular urine analysis every 6-8 weeks (and whenever the child has a fever), periodic radiologic studies every 12 months or so, and prophylactic long-term, low-dose antibiotics.
The premise for this approach is that reflux has a tendency to resolve or to improve with age, and scarring can be prevented if sterile urine is maintained. The mean time for spontaneous resolution from initial presentation is about 3 years.
Resolution of reflux may occur in 60% to 85% of non-dilated ureters and 25% to 40% of dilated ureters, and younger patients may have a greater chance of resolution.
Children with reflux and frequency/urgency and/or urge incontinence (due to bladder instability) may benefit from the addition of Ditropan or another bladder antispasmodic to their low dose antibiotics. In these patients, this medication can speed resolution of the reflux.
Several years of medical management can entail 30-40 urine cultures, many office visits and several radiological examinations. In addition, prolonged antibiotic treatment, cost, anxiety, risks and inconvenience of such non-surgical management need to be weighed against the success of surgery and its possible downsides of continuing reflux or obstruction.
Surgery is considered in those who have:
- Breakthrough UTIs
- Scar progression
- Reflux and hydronephrosis in an older child where resolution is unlikely
- Failure of conservative trial in a child with reflux associated with hydronephrosis
- Worsening of reflux
- Reflux in female adolescent
- Associated defects such as duplex ureters
Endoscopic outpatient correction of reflux by injecting a material adjacent to the ureteral orifice through a cystoscope will cure most patients.(See www.deflux.com)
More formal surgery may be accomplished through transvesical or extravesical approaches suprapubically (“bikini incision”) and reimplanting the ureters. Stents may or may not be used. A foley catheter is usually removed towards the end of the 2-3 day hospitalization. A penrose drain is removed in the office at a later date. The correction success rate is in the order of 98%.
Laparoscopic approaches for correcting reflux are uncommon since most can be corrected endoscopically.