Vesicoureteral Reflux (VUR)

What Is Vesicoureteral Reflux (VUR)? What Causes Vesicoureteral Reflux?

Vesicoureteral reflux, also known as VUR is when urine flows in the wrong direction, from the bladder back into the ureters. Urine should normally flow from the kidneys, down through tubes called ureters, and into the bladder. Vesicoureteral reflux diagnosis usually occurs during infancy (babyhood) and childhood following a urinary tract infection (UTI).

Approximately 30% of all children with a urinary tract infection are found to have vesicoureteral reflux. VUR raises the risk of infection, because stagnant urine in the urinary tract is an ideal environment for bacteria to thrive. However, sometimes it is the other way round, with the infection causing the VUR (vesicoureteral reflux).

There are two types of VUR:

  • Primary vesicoureteral reflux (primary VUR) - the baby is born with a faulty valve located where the ureter and the bladder join. This occurs when the ureter is too short, the valve does not close as it should, allowing urine to back up (reflux) from the bladder to the ureters, eventually making its way back to the kidneys.

    Primary VUR can improve as the child gets older, sometimes the problem can go away altogether. As the child grows, so does the ureter and valve function improves.
  • Secondary vesicoureteral reflux (secondary VUR) - there is a blockage somewhere in the urinary system, caused possibly by a bladder infection that makes the ureter swell, resulting in urine reflux to the kidneys.
If VUR is left untreated it can lead to kidney damage.

According to Medilexicon's medical dictionary:
    Vesicoureteral reflux is "backward flow of urine from bladder into ureter."

What are the signs and symptoms of vesicoureteral reflux (VUR)?

A symptom is something the patient senses and describes, while a sign is something other people, such as the doctor notice. For example, drowsiness may be a symptom while dilated pupils may be a sign.

Each VUR patient, usually a child or baby, may experience symptoms differently.

Urinary tract infection

The most common indication of VUR in children or babies is a urinary tract infection, which may itself occasionally develop without noticeable signs and symptoms. Urinary tract infections are uncommon in patients younger than 5 years, and unlikely in boys of any age, unless they have VUR.

Most common signs and symptoms of urinary tract infection are:
  • Urgency to urinate
  • Dysuria - Burning sensation (pain) when urinating
  • Hematuria - blood in urine
  • Urine may be cloudy
  • Malodorous urine - urine has a strong, unpleasant smell
  • Dribbling of urine
  • Wetting pants
  • There may be an abdominal mass felt, which is caused by a swollen kidney
  • Poor weight gain
  • Fever - elevated body temperature (pyrexia)
  • Abdominal pain - this pain may also be felt on the side (flank)
  • Hypertension - high blood pressure (as child gets older, if VUR is left untreated)
  • Bed wetting (as child gets older, if VUR is left untreated)
  • Kidney failure (as child gets older, if VUR is left untreated)
  • Protein in urine (as child gets older, if VUR is left untreated)
An infant (very young baby) may have vomiting, diarrhea, lethargy, and failure to thrive (not growing normally).
When to see a doctor - if the child has a strong and persistent urge to urinate, experiences a burning sensation when urinating, and has abdominal or flank pain, he/she should be seen by a doctor.

If the child is less than three months old and has a temperature of 38C (100.4F), or is over 3 months old and has a temperature of 38.9C (102F) you should contact a doctor.

If an infant is refusing food, eats poorly, is lethargic, difficult to wake up, has inconsolable crying, diarrhea, or vomiting call a doctor.

What are the risk factors for vesicoureteral reflux (VUR)?

A risk factor is something which increases the likelihood of developing a condition or disease. For example, obesity significantly raises the risk of developing diabetes type 2. Therefore, obesity is a risk factor for diabetes type 2.
  • Gender - VUR is considerably more common in girls than boys.
  • Race - Caucasian children are more likely to have VUR than other children.
  • Age - infants and very young children have a higher risk of having VUR, compared to older children or adults.
  • Genetics - a child who has a parent who had primary VUR has a higher risk of having it himself/herself than other children. If one child has primary VUR, the likelihood that his/her sibling will also have it is higher. Many doctors will advise screening for VUR if it has already appeared in the family.

What are the causes of vesicoureteral reflux (VUR)?

The human urinary system - consists of the:
  • Urethra - a tube from the bladder through which urine passes and is discharged out of the body. In males it travels through the penis and carries semen as well as urine. In females it emerges above the vaginal opening.
  • Bladder (urinary bladder) - a hollow organ, like a bag or sac, which holds urine.
  • Ureters - tubes from the kidneys to the bladder, through which urine travels. There are two of them, one from each kidney.
  • Kidneys - typically, there are two of them. These organs clear toxins from blood, regulate acid concentrations, and maintain water balance in the body by excreting urine, which travels down the ureters to the bladder.
In Primary vesicoureteral reflux (primary VUR) the baby is born with the condition. A valve between the bladder and ureter does not work properly - it does not close properly. Mainly because the ureter did not develop to a long-enough length. In most cases, as the child grows, so does the length of the ureter, and the problem resolves. Primary VUR is thought to be genetic, because it runs in families.

In secondary vesicoureteral reflux (secondary VUR) there is a blockage in the urinary system, often caused by urinary tract infection, resulting in inflammation (swelling) of a ureter.

How is vesicoureteral reflux (VUR) diagnosed?

VUR can sometimes be diagnosed before birth during an ultrasound scan.

Urine test - a urinalysis (lab analysis of urine) can reveal whether the patient has a urinary tract infection.

The doctor may also order the following tests to either confirm or rule out VUR:
  • Ultrasound scan of the bladder and kidneys - this device uses ultrasound waves which bounce off tissues; the echoes are converted into a sonogram (an image) which the doctor can see on a monitor. The doctor can get an inside view of soft tissues and body cavities.
  • VCUG (Voiding cystourethrogram) - this test looks at the bladder and urethra while the bladder fills and empties. Patients lie on their back on an X-ray table and a catheter is inserted through the urethra and into the bladder. A contrast liquid dye which shows up on X-rays is injected through the catheter and into the bladder, filling it up. Pictures are taken when the bladder is filled and when the patient urinates. The test reveals abnormalities of the inside of the urethra and bladder. It can also determine whether urine flow is normal when the bladder empties.

    There is a slight risk of developing a urinary tract infection, discomfort during urination, and having an allergic reaction to the dye (bladder spasms).
  • Nuclear scan - radioactive material is injected into a vein to show how well the kidneys work, whether they have the right shape, and whether urine empties normally from the kidneys. Nuclear scans do not expose the patient to any more radiation than a conventional X-ray does.

    A radionuclide cystogram uses a radioisotope (radioactive material) which is injected into the bladder through a catheter which has been inserted into the urethra - the test shows how well the urinary tract is working. After the test the patient's urine may be pink for a couple of days. There may be discomfort during urination.
Grading the vesicoureteral reflux - the grading system reflex the degree of reflux:
  • Grade I - reflux into non-dilated ureter
  • Grade II - reflux into the renal pelvis and calyces without dilatation
  • Grade III - mild/moderate dilatation of the ureter, renal pelvis and calyces with minimal blunting of the fornices
  • Grade IV - dilation of the renal pelvis and calyces with moderate ureteral tortuosity
  • Grade V - gross dilatation of the ureter, pelvis and calyces; ureteral tortuosity; loss of papillary impressions
The majority of Grades I and II will resolve spontaneously (suddenly get better on their own).

What are the treatment options for vesicoureteral reflux (VUR)?

Vesicoureteral reflux can have varying degrees of severity, from mild reflux, when urine backs up just a short distance into the ureters, to severe reflux, which can result in kidney infections and permanent kidney damage. Treatment options will depend on:
  • The patient's age
  • The patient's overall health
  • The patient's medical history
  • The severity of the patient's condition
  • The patient's tolerance to certain procedures, therapies or medications
  • The parent's (or patient's) preference
  • And the expectations for the course of the VUR
Many children with mild primary VUR will eventually grow and the disorder will resolve on its own; in such cases the doctor will recommend "watchful waiting". During this period parents/guardians will need to look out for possible urinary tract infections.

Patients with moderate to severe primary VUR may require medication or surgery. Medication is more commonly used, while surgery is an option if medications (usually antibiotics) have not been effective.

Those with Grades IV and V may undergo surgery as a first line therapy.

Medications - patients with urinary tract infections need antibiotics to prevent it from reaching the kidneys. Antibiotics may also be used to prevent a urinary tract infection. Preventive doses are much lower.

The following medications may be used:
  • Trimethoprim-sulfamethoxazole (Bactrim, Septra)
  • Trimethoprim (Primsol)
  • Nitrofurantoin (Furadantin, Macrobid, Macrodantin)
Side effects may include vomiting, nausea, abdominal pain, and increased antibiotic resistance.

It is important to monitor the patient closely and detect any breakthrough infections.

Surgery - this involves repairing the faulty valve between the affected ureter and the bladder. The valve needs to be fixed so that it prevents urine from backing up into the ureter. During the procedure the surgeon creates a flap-valve apparatus for the ureter that prevents reverse flow of urine (reflux) into the kidney. In very severe cases the scarred ureter and kidney may have to be surgically removed.

There are three types of surgical procedure available for the treatment of VUR: endoscopic, laparoscopic, and open procedures.

What are the possible complications of vesicoureteral reflux (VUR)?

The complication of most concern is kidney damage. In severe cases of VUR this is a serious risk.

Renal scarring (kidney scarring) - if the urinary tract infection is left untreated there is a significant risk of renal scarring, also known as reflux nephropathy, which can result in permanent kidney damage.

Hypertension - high blood pressure. If the kidneys do not work properly, there is an accumulation of toxins in the blood, which can lead to high blood pressure.

Acute kidney failure - toxins may build up in the blood rapidly because of loss of kidney function. The patient will need emergency dialysis.

Chronic kidney function - the kidneys gradually lose function. If function goes down to below 15% of normal capacity the patient is in end-stage kidney disease. He/she will either require a new kidney (transplant) or regular dialysis. Chronic means long-term.

 

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