Vesicoureteric Reflux (VUR)

Vesicoureteric reflux

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My son has recurrent urinary tract infection, and the doctor diagnosed vesicoureteric reflux (VUR). What is it?

Vesicoureteric reflux (VUR) is a defect in the tube carrying urine from the kidney to the bladder (ureter), allowing urine to backflow from the bladder into the ureter. When this happens, there is the risk of urinary stasis and urinary tract infection (UTI). The backflow pressure also risks damage to the kidney resulting in focal renal scarring. There is a risk of renal dysplasia, hypertension and renal failure.

What causes vesicoureteric reflux (VUR)?

The reason for vesicoureteric reflux (VUR) is multifactorial and due to both congenital and acquired causes. Young children have an immature ureter – bladder junction, often resulting in mild reflux. Children of parents with VUR tend to develop reflux, while others arise anew. Pee and poo (bladder and bowel) dysfunction often results in VUR due to chronic high pressure on the ureter openings. A urinary tract infection can cause bladder inflammation resulting in transient VUR.

How is vesicoureteric reflux (VUR) diagnosed?

Vesicoureteric reflux (VUR) is diagnosed on a micturating cystourethrogram (MCU). The MCU is performed using a type of X-ray while contrast is injected via a urinary catheter. This allows visualization of the lower urinary tract (urethra and bladder), and detects vesicoureteric reflux. Severe reflux occurs during the filling phase, with smaller volumes of contrast, and dilates the kidney collecting system. The MCU is performed when the child is awake, and sedation can be given to make the process less traumatic for him/her.

How is vesicoureteric reflux treated?

When asymptomatic, I advise to leave the vesicoureteric reflux alone and monitor the urinary system with serial ultrasounds. With increasing age, there is a good chance that mild vesicoureteric reflux resolves with maturation of the ureter-bladder junction. When symptomatic, for example with urinary tract infection (UTI), it is treated with continual antibiotic prophylaxis (CAP), cystoscopic Deflux injection or ureteric reimplantation. CAP is reported to prevent recurrent UTI in some studies, but not in others. Antibiotics does not improve or prevent renal scarring from the reflux back pressure effect(1). With prolonged courses, specific antibiotic resistance develops and requires changing. Surgical intervention is indicated when there is breakthrough UTI, intolerance to antibiotics or patient / parental preference. Intolerance to antibiotics presents as diarrhea, loss of weight, refractory perianal excoriations, and allergy.

What is done during a cystoscopic Deflux injection?

Under general anaesthesia, a fine scope is inserted via the urethra into the bladder. Any anomalies found along the urinary tract is treated via the scope. The ureter openings’ position and dilatation are assessed and treated by Deflux injection. Deflux is a polymer which works by occluding the bladder – ureter junction, and achieves resolution of reflux in up to 95% of patients(2). The polymer is partly absorbed by the body, and the remainder may become calcified and appear as white opacities in the pelvis in future. Post Deflux injection, I give a memo to my patients to ensure that a proper medical history is available for another treating doctor.

What are the risks of a cystoscopic Deflux injection?

There is a <1% risk of bleeding and ureteric obstruction(3). There is a risk of recurrent vesicoureteric reflux (VUR), up to 5% in moderate VUR, and 30% in severe VUR. When there is recurrent VUR and urinary tract infection, I discuss repeat cystoscopic Deflux injection. When there is a second recurrence, I offer ureteric reimplantation to the patient.

What other ways are there to prevent a recurrent urinary tract infection, besides Deflux?

Symptoms and signs of pee and poo (bladder – bowel) dysfunction are assessed, and if present, started on treatment. Urotherapy, biofeedback and medication resolves the symptoms of bladder bowel dysfunction. I discuss continual antibiotic prophylaxis, its benefits and risks, with my patients. Probiotics and tannins in cranberry juice have also been found in a few studies to help prevent recurrent UTI. For a boy, when cystoscopic Deflux is chosen as the treatment, I recommend circumcision under the same anaesthesia setting. This decreases the risk of a recurrent UTI by removing the foreskin and ensuring an unobstructed urinary stream. Patients with severe VUR and breakthrough UTI, or recurrent VUR despite Deflux treatment, benefit from open ureteric reimplantation.

References

  1. RIVUR Trial Investigators, Hoberman A, Greenfield SP, et al. Antimicrobial prophylaxis for children with vesicoureteral reflux. N Engl J Med. 2014 Jun 19;370(25):2367–76.
  2. Lightfoot M, Bilgutay AN, Tollin N, et al. Long-Term Clinical Outcomes and Parental Satisfaction After Dextranomer/Hyaluronic Acid (Dx/HA) Injection for Primary Vesicoureteral Reflux. Front Pediatr. 2019;7:392.
  3. Friedmacher F, Puri P. Ureteral Obstruction After Endoscopic Treatment of Vesicoureteral Reflux: Does the Type of Injected Bulking Agent Matter? Curr Urol Rep. 2019 Jul 9;20(9):49.