Vesicoureteral reflux

Definition : Vesicoureteral reflux is the abnormal flow of urine from the urinary bladder back up the ureters (tubes that connect your kidneys to your bladder). Normally, urine flows only down from your kidneys to your bladder.

Vesicoureteral reflux is usually diagnosed in infants and children. The disorder increases the risk of urinary tract infections, which, if left untreated, can lead to kidney damage.

Vesicoureteral reflux can be primary or secondary. Children with primary vesicoureteral reflux are born with a defect in the valve that normally prevents urine from flowing backward from the bladder into the ureters. Secondary vesicoureteral reflux is due to a urinary tract malfunction, often caused by infection.

Children may outgrow primary vesicoureteral reflux. Treatment, which includes medication or surgery, aims at preventing kidney damage.

VUR may cause recurrent urinary tract infections (UTI) and UTI may be difficult to diagnose in children, who may have only nonspecific signs and symptoms. Signs and symptoms in infants with a UTI may also include:

• An unexplained fever
• Diarrhea
• Lack of appetite
• Irritability

As your child gets older, untreated vesicoureteral reflux can lead to other signs and symptoms, including:

• Bed-wetting
• Constipation or loss of control over bowel movements
• High blood pressure
• Protein in urine
• Kidney failure

Another indication of vesicoureteral reflux, which may be detected before birth by sonogram, is swelling of the kidneys or the urine-collecting structures of one or both kidneys (hydronephrosis) in the fetus, caused by the backup of urine into the kidneys.

Figure 1: Grading

When to suspect VUR

Contact your doctor right away if your child develops any of the signs or symptoms of a UTI, such as:

• A strong, persistent urge to urinate
• A burning sensation when urinating
• Abdominal or flank pain
• A hesitancy to urinate

Call your doctor about fever if your child:

• Is younger than 3 months old and has a rectal temperature of 38 C or higher
• Is 3 months or older and has a fever of 102 F (38.9 C) or higher without any other explainable factors, such as a recent vaccination

In addition, call your doctor immediately if your infant has the following signs or symptoms:

• Changes in appetite. If your baby refuses several feedings in a row or eats poorly, contact the doctor.
• Changes in mood. If your baby is lethargic or unusually difficult to rouse, tell the doctor right away. Also let the doctor know if your baby is persistently irritable or has periods of inconsolable crying.
• Contact the doctor if several of your baby’s stools are especially loose or watery.
• Occasional spitting up is normal. Contact the doctor if your baby spits up large portions of multiple feedings or vomits forcefully after feedings.

Figure 2

Causes

Vesicoureteral reflux can develop in two forms, primary and secondary:

• Primary vesicoureteral reflux. The cause of this more common form is a defect that’s present before birth (congenital). The defect is in the functional valve between the bladder and a ureter that normally closes to prevent urine from flowing backward.
As your child grows, the ureters lengthen and straighten, which may improve valve function and eventually resolve the reflux. This type of vesicoureteral reflux tends to run in families, which indicates that it may be genetic, but the exact cause of the defect is unknown.
• Secondary vesicoureteral reflux. The cause of this form is a blockage or malfunction in the urinary system. The blockage most commonly results from recurrent UTIs, which may cause swelling of a ureter.

 

Risk factors for vesicoureteral reflux include:

• White children appear to have a higher risk of vesicoureteral reflux.
• Generally, girls have about double the risk of having this condition as boys do. The exception is for vesicoureteral reflux that’s present at birth, which is more common in boys.
• Infants and children up to age 1 are more likely to have vesicoureteral reflux than older children are.

Family history. Primary vesicoureteral reflux tends to run in families. Children whose parents had the condition are at higher risk of developing it.

Siblings of children who have the condition also are at higher risk, so your doctor may recommend screening for the siblings of a child with primary vesicoureteral reflux.

Kidney damage is the primary concern with vesicoureteral reflux. The more severe the reflux, the more serious the complications are likely to be.

Complications may include:

• Kidney (renal) scarring. Untreated UTIs can lead to scarring, also known as reflux nephropathy, which is permanent damage to kidney tissue. A backup of urine exposes the kidneys to higher than normal pressure.

If your kidneys are infected, this can lead to scarring over time. Extensive scarring may lead to high blood pressure and kidney failure.
• High blood pressure (hypertension). Because the kidneys remove waste from the bloodstream, damage to your kidneys and the resultant buildup of wastes can raise your blood pressure.
• Kidney failure. Scarring can cause a loss of function in the filtering part of the kidney. This may lead to kidney failure, which can occur quickly (acute) or may develop over time (chronic)

 

Diagnosis

Urinalysis — lab analysis of a urine sample — can reveal whether your child has a UTI. Other tests are necessary to determine the presence of vesicoureteral reflux, including:

• Kidney and bladder ultrasound. This imaging method uses high-frequency sound waves to produce images of the kidney and bladder. Ultrasound can detect structural abnormalities.

This same technology, often used during pregnancy to monitor fetal development, may also reveal swollen kidneys in the baby, an indication of primary vesicoureteral reflux.
• Voiding cystourethrogram (VCUG). This test uses X-rays of the bladder when it’s full and when it’s emptying to detect abnormalities. A thin, flexible tube (catheter) is inserted through the urethra and into the bladder while your child lies on his or her back on an X-ray table.
After contrast dye is injected into the bladder through the catheter, your child’s bladder is X-rayed in various positions. Then the catheter is removed so that your child can urinate, and more X-rays are taken of the bladder and urethra during urination to see whether the urinary tract is functioning correctly.
Risks associated with this test include discomfort from the catheter or from having a full bladder and the possibility of a new urinary tract infection.
• Nuclear scan. This test, known as radionuclide cystogram, uses a procedure similar to that used for VCUG, except that instead of dye being injected into your child’s bladder through the catheter, this test uses a radioactive tracer (radioisotope). The scanner detects the tracer and shows whether the urinary tract is functioning correctly.
Risks include discomfort from the catheter and discomfort during urination. Your child’s urine may be slightly pink for a day or two after the test.

Grading the condition

Vesicoureteral reflux is graded according to the degree of reflux (Figure 1). In the mildest cases, urine backs up only to the ureter (grade I). The most severe cases involve severe kidney swelling (hydronephrosis) and twisting of the ureter (grade V).

Treatments and drugs

 

Treatment options for vesicoureteral reflux depend on the severity of the condition. Children with mild cases of primary vesicoureteral reflux may eventually outgrow the disorder. In this case, your doctor will likely recommend a wait-and-see approach.

For more severe vesicoureteral reflux, treatment options include:

 

Medications

UTIs require prompt treatment with antibiotics to keep the infection from moving to the kidneys. To prevent UTIs, doctors may also prescribe antibiotics at a lower dose than for treating an infection.

A child being treated with medication needs to be monitored for as long as he or she is taking antibiotics. This includes periodic physical exams and urine tests to detect breakthrough infections — UTIs that occur despite the antibiotic treatment — and occasional radiographic scans of the bladder and kidneys to determine if your child has outgrown vesicoureteral reflux.

Surgery

Surgery for vesicoureteral reflux repairs the defect in the functional valve between the bladder and each affected ureter (Figure 2) that keeps it from closing and preventing urine from flowing backward.

Methods of surgical repair include:

• Open surgery. Performed using general anesthesia, this surgery requires an incision in the lower abdomen through which the surgeon repairs the malformation that’s causing the problem.
This type of surgery usually requires a few days’ stay in the hospital, during which a catheter is kept in place to drain your child’s bladder. Vesicoureteral reflux may persist in a small number of children, but it generally resolves on its own without need for further intervention.
• Robotic-assisted laparoscopic surgery. Similar to open surgery, this procedure involves repairing the valve between the ureter and the bladder, but it’s performed using small incisions. Preliminary findings suggest that robotic-assisted laparoscopic surgery has similar success rates to open surgery. It was also associated with a longer operating time, but a shorter hospital stay.
• Endoscopic surgery. In this procedure, the doctor inserts a lighted tube (cystoscope) through the urethra to see inside your child’s bladder, then injects a bulking agent around the opening of the affected ureter to try to strengthen the valve’s ability to close properly.
This method is minimally invasive compared with open surgery and presents fewer risks, though it may not be as effective. This procedure also requires general anesthesia, but generally can be performed as outpatient surgery.