flows in one direction--down from the kidneys, through tubes called
ureters, to the bladder. Vesicoureteral reflux (VUR) is the abnormal
flow of urine from the bladder back into the ureters.
|Normal urinary system
Urinary system with reflux
VUR is most commonly diagnosed in infancy and childhood after the
patient has a urinary tract infection (UTI). About one-third of
children with UTI are found to have VUR. VUR can lead to infection
because urine that remains in the child's urinary tract provides a
place for bacteria to grow. But sometimes the infection itself is
the cause of VUR.
Pathophysiology: Reflux nephropathy is based on persistent
reflux of sterile or infected urine from the bladder to one or both
kidneys via the ureters. Although sterile VUR may cause renal
scarring, most studies indicate that the appearance of renal
scarring or the extension of established renal scars requires
infection (Escherichia coli is the common pathogen). The higher the
grade of reflux, the greater the likelihood of development of new or
progressive scarring in association with infection.
Intrarenal reflux, or the extension of VUR into the collecting
tubules of the nephrons that allows urinary microorganisms access to
the renal parenchyma, is believed to be particularly important in
the development of renal scarring.
Radiologic evidence of renal scarring is noted in 30-60% of children
with VUR, and VUR is present in almost all children with severe
renal scarring. A direct correlation between the prevalence of
scarring and the grade of VUR has been demonstrated.
Although VUR occurs at a similar rate in boys and girls, girls are
at greater risk of developing reflux nephropathy because of
increased incidence of urinary tract infection (UTI). In the absence
of reflux and UTI, abnormalities of organ systems other than the
genitourinary tract do not place a child at increased risk for
developing reflux nephropathy.
In the US: The incidence of renal scarring in children resulting
from VUR is unknown. The prevalence of VUR in asymptomatic children
is less than 0.5%, but VUR is present in 29-50% of children with
Mortality/Morbidity: The incidence of renal scarring in children
caused by VUR is unknown. VUR is present in 29-50% of children with
Race: VUR and reflux nephropathy occur less frequently in black
children than in other groups of patients.
Sex: Reflux occurs at a similar rate in boys and girls; however, the
much higher incidence of UTI in girls places them at greater risk
for reflux nephropathy.
Age: In children, the occurrence of VUR decreases with increasing
age. The vesicoureteral insertion matures just prior to puberty. The
mature bladder wall intramural portion of the ureter attains its
Anatomy: Most VUR is considered primary because of
incompetence of the ureterovesical junction (UVJ), and it is not
secondary to either obstruction or infection. As the UVJ matures to
assume its adult 1.5-cm oblique path through the bladder wall, VUR
tends to decrease in severity and eventually disappears just before
puberty. An exception is in patients with an anatomic abnormality,
such as a bladder diverticulum, into which the refluxing ureter
enters. Incompetence of the vesicoureteral junction resulting from a
lack of maturation is the most common cause of vesicoureteral reflux
in children. Obstruction and infection rarely cause reflux. With
maturation of the incompetent vesicoureteral junction, reflux
usually eventually resolves.
A small subgroup of children who have a perpendicular ureteric
insertion at the bladder wall with a resultant golf-hole ureteric
orifice. In these patients, surgical correction is necessary to
eliminate VUR. A decision to perform a repair, either a
ureteroneocystostomy or a collagen periurethral injection is
dependent upon the appearance of the ureteric orifice. Nevertheless,
all patient are covered with appropriate antibiotics to await the
maturation of the intramural portion of the ureter or undergo
surgery to stop the reflux.
Clinical Details: Children with reflux nephropathy may be
asymptomatic, they may present with nonspecific symptoms (eg,
failure to thrive, fever, poor food intake), they may be acutely ill
in association with acute pyelonephritis, or they may present with
renal failure with advanced renal scarring associated with reflux
Urinary reflux often takes urine back up to the kidneys, leading
to the possibility of kidney infection (Pylonephritis) and permanent
kidney damage (scarring) in young children.
Poor weight gain
Pain on urination
Strong smelling urine
Bed wetting if previously dry
Blood in the urine
General ill health
There are two types of VUR. Primary VUR occurs when a child is born
with an impaired valve where the ureter joins the bladder. This
happens if the ureter did not grow long enough during the child's
development in the womb. The valve does not close properly, so urine
backs up (refluxes) from the bladder to the ureters, and eventually
to the kidneys. This type of VUR can get better or disappear as the
child gets older. The ureter gets longer as the child grows, and the
function of the valve improves.
Secondary VUR occurs when there is a blockage anywhere in the
urinary system. The blockage may be caused by an infection in the
bladder that leads to swelling of the ureter. This also causes a
reflux of urine to the kidneys.
Infection is the most common symptom of VUR. As the child gets
older, other symptoms, such as bedwetting, high blood pressure,
protein in the urine, and kidney failure, may appear.
Common tests to show the presence of urinary tract infection include
urine tests and cultures.
Because no single test can tell everything about the urinary tract
that might be important to know, more than one of the following
imaging tests may be needed:
Kidney and bladder ultrasound: A test that uses sound waves
to examine the kidney and bladder. This test shows shadows of the
kidney and bladder that may point out certain abnormalities. The
test cannot reveal all important urinary abnormalities or measure
how well a kidney works.
Ultrasound showing VCR from http://www.emedicine.com
Voiding cystourethrogram (VCUG): A test that examines the
urethra and bladder while the bladder fills and empties. A liquid
that can be seen on x rays is placed in the bladder through a
catheter. Pictures are taken when the bladder is filled and when the
child urinates. This test can reveal abnormalities of the inside of
the urethra and bladder. The test can also determine whether the
flow of urine is normal when the bladder empties.
VCUG Results grading
Grade I Ureter only
Grade II Ureter pelvis, and calyces with out dilation.
Grade III Mild dilation of ureter, slight blunting of calyceal
Grade IV Moderate dilation, loss of sharp calyceal fornices
Grade V Gross dilation of ureter and calyces
III Mild dilation of ureter, slight blunting of calyceal fornices
Bilateral reflux extending into
the pelvicalyceal systems of the kidney without dilatation of the
calyces or ureters. (Note catheter in bladder)
Intravenous pyelogram: A test that examines the whole urinary
tract. A liquid that can be seen on x rays is injected into a vein.
The substance travels into the kidneys and bladder, revealing
Nuclear scans: A number of tests using radioactive materials
that are usually injected into a vein to show how well the kidneys
work, their shape, and whether urine empties from the kidneys
normally. Each kind of nuclear scan gives different information
about the kidneys and bladder. Nuclear scans expose a child to about
the same amount of radiation as a conventional x ray. At times, it
can be even less.
The goal for treatment of VUR is to prevent any kidney damage
from occurring. Infections should be treated at once with
antibiotics to prevent the infection from moving into the kidneys.
Antibiotic therapy usually corrects reflux caused by infection.
Sometimes surgery is needed to correct primary VUR.
Most cases of uncomplicated mild reflux will disappear over time.
Meanwhile, your child will need to take a single, low dose of
antibiotics daily to prevent kidney infection, and will need a
voiding cystourethrogram and renal ultrasound once a year. Long-term
antibiotic treatment is usually with trimetroprim/ sulfamethoxazole
(Bactrim, Septra) or nitrofurantoin (Macrodantin, Furadantin,
Macrobid). For infants under two months of age, amoxicillin or
ampicillin is usually used. In addition, your doctor should check a
urine culture 3-4 times per year.
There is a new procedure that we are now offering to treat
vesicoureteral reflux. The medication used is called Deflux. During
the 20-minute procedure the Deflux is injected into the lining of
the bladder to make a new valve mechanism and stop the reflux. In
80% of the children who undergo this procedure, the reflux and the
use of daily antibiotics are eliminated. The procedure is done under
an anaesthetic as an out patient surgical procedure which is
minimally invasive and does not involve any incisions.
In some cases of reflux, your doctor may recommend surgery. Reasons
for surgery include severe (Grade 4 or 5) reflux, which is not
likely to get better on its own, infections despite daily
antibiotics, and reflux which has persisted after several years of
observation. During the surgery, the ureter will be disconnected
from the bladder and then reimplanted so it canít reflux. Our
patientsí average hospital stay after this surgery, using
state-of-the-art pain management techniques, is little more than a
day. Although success rates for reimplant surgery are about 98
percent, surgical complications are possible.