Family doctor

Overview:

• Vescicoureteric reflux is the backwards flow of urine from the bladder towards the kidneys
• The condition is associated with urinary tract infections especially in children
• Reflux combined with infections can cause kidney damage
• Investigation of children with urinary infections is important to detect the condition
• Reflux can resolve in children without intervention
• Antibiotics are used to prevent infections until the condition resolves
• Surgery is necessary to correct severe cases of urinary reflux

What is it?

This is the condition which results in a backwards flow of urine from the bladder into the upper urinary tract. The cause of reflux is unknown, but it appears in most cases to result from a short ureteric tunnel through the bladder wall. This submucosal tunnel usually effectively acts as a valve, as the bladder contracts, preventing urine from ascending up the ureter. Sometimes the back wall of the ureter or bladder is not supportive, resulting in a "diverticulum" (out-pouching) or the bladder wall, resulting in reflux.

In addition, rarely patients may have duplicated ureters - i.e. 2 ureters on one or both sides. Duplicated ureters may be refluxing as these may have a ureteric opening further out to the side, with less tunneling through the bladder wall.

Reflux is associated with urine infection. It is still controversial as to whether reflux alone can cause renal damage, however reflux associated with urinary infection can cause renal infection, renal scarring and progressive renal failure (a condition known as reflux nephropathy).

Epidemiology:

The incidence of reflux in the normal child is unknown, but is probably less than 1%. When urine infection is the reason for investigation the incidence of reflux is 20-50%, and this decreases with advancing age.

Siblings of children with reflux have a 30% incidence of reflux.

Grading:

The international grading system for reflux is based primarily on the X-ray appearance of the kidney collecting system on the cystogram.

Diagnosis:

All children under 5 years of age who present with a urinary tract infection are recommended in addition to having an ultrasound examination of the renal tract to have a cystogram. A cystogram is an unpleasant examination where a catheter tube is passed through the urethra into the bladder. The bladder is then filled with contrast (dye) and X-rays are taken during filling and when children are urinating, to see if the dye goes back up to the kidney.

Although this examination is unpleasant, it is very important to detect patients with reflux, because untreated reflux can cause renal scarring and occasionally renal failure.

Treatment of reflux:

Spontaneous resolution of reflux occurs throughout childhood. This is most likely within the first few months to years following the diagnosis, however the rate is still relatively constant throughout childhood, being approximately 10% per year.

Generally low-grade reflux (Grade 1 and Grade 2) is treated with medical management - this is "antibiotic prophylaxis" - until the reflux spontaneously resolves.

Grade 5 or severe, high-grade reflux is usually treated with surgery - this is "ureteric reimplantation", an operation designed to lengthen the ureteric tunnels.

There have been several large studies looking at medical versus surgical treatment of moderate grade (Grade 3 and Grade 4) reflux, to try to see if there is any difference in outcome. The advantages of surgery are that the reflux stops immediately; with an experienced reflux surgeon, the operation is successful in over 95% of cases.

Continuing antibiotics prophylaxis is not required following surgery (often for several weeks).

With medical treatment, it is unpredictable which patients with moderate grade reflux will have spontaneous resolution of the reflux, and antibiotic prophylaxis needs to be continued until the reflux has resolved. This requires close follow-up of the patient, often with annual renal ultrasounds to assess ongoing renal growth, and to detect whether scarring is present. Further investigations may be required, as they are more accurate in determining renal function and the presence of renal scars.

Usually every second year a cystogram is also required, to check to see if reflux has resolved. The outcome of both medical and surgical treatment has been similar in terms of renal growth and scarring, however, the medically treated group may have an increased risk of renal infection.

Management:

Initially all children diagnosed with reflux should be placed on prophylactic (preventative antibiotics) at the normal treatment dose. Commonly used medications for this include trimethoprim - sulfamethoxazole, nitrofurantoin or cephaclor.

Problems resulting from long-term, low-dose antibiotics are extremely rare, and patients who are treated medically need to continue on these. Relative indications for surgery include breakthrough infections on antibiotic prophylaxis, a failure of patients to comply with antibiotics (which is relatively common), or persistent reflux into puberty in females. If the reflux is increasing in grade, or progressive renal scarring and worsening renal function are occurring, most urologists would favour surgical intervention, but there are no absolute indications for surgery in reflux.

Surveillance:

Regardless of whether patients have medical or surgical treatment, continued surveillance is necessary after reflux has either stopped spontaneously, or after anti-reflux surgery, as urinary tract infections can occur, and require recognition and treatment.

Other complications:

Hypertension and proteinuria are well-known long-term complications encountered in adults and children with reflux and renal scarring.

Despite resolution of the reflux, a small number of patients develop progressive renal failure.

Screening:

Many practitioners recommend that siblings of children who have reflux are screened, at least with ultrasound, and they probably should have a cystogram if they are under 5 years of age, as approximately 30% of siblings will have reflux.