(See also Overview of Kidney Filtering Disorders Overview of Kidney Filtering Disorders Each kidney contains about 1 million filtering units (glomeruli). The glomeruli are made up of many microscopic clusters of tiny blood vessels (capillaries) with small pores. These blood vessels... read more .)
Normally, where the bladder and the ureter join, the ureter tunnels slightly sideways through the bladder wall. The muscles of the bladder wall help keep the end of the ureter shut so that urine flows in only one direction—from the ureter into the bladder. Some people are born with abnormalities of the junction between the ureter and bladder that allow the urine to flow backward during urination—from the bladder into the ureters. This condition is called vesicoureteral reflux (VUR). It can occur in one or both ureters. The backward flow of urine makes urinary tract infections Overview of Urinary Tract Infections (UTIs) In healthy people, urine in the bladder is sterile—no bacteria or other infectious organisms are present. The tube that carries urine from the bladder out of the body (urethra) contains no bacteria... read more (UTIs) more likely to develop and to cause kidney inflammation and scarring, a condition called reflux nephropathy.
About 30 to 45% of children and about 1% of newborns who have a UTI that causes a fever have VUR. VUR sometimes tends to run in families and is less common among Black people. Children usually outgrow VUR by about age 5 years.
VUR causes no symptoms, but children with VUR tend to have repeated UTIs. Reflux nephropathy causes no symptoms. Occasionally, children with reflux nephropathy develop chronic kidney disease Chronic Kidney Disease Chronic kidney disease is a slowly progressive (months to years) decline in the kidneys’ ability to filter metabolic waste products from the blood. Major causes are diabetes and high blood pressure... read more , sometimes during adolescence.
Doctors suspect vesicoureteral reflux (VUR) in the following children:
Those with a UTI at age 3 years or younger
Those with UTI and fever at age 5 years or younger
Those with repeated UTIs
Boys at any age with a UTI
Doctors sometimes also suspect VUR in children with close relatives who have the disorder and in children or adults who have repeated urinary tract infections Overview of Urinary Tract Infections (UTIs) In healthy people, urine in the bladder is sterile—no bacteria or other infectious organisms are present. The tube that carries urine from the bladder out of the body (urethra) contains no bacteria... read more (UTIs) and in whom imaging tests show kidney scarring.
Doctors may suspect that a fetus has VUR if routine prenatal ultrasonography shows a swollen kidney (called hydronephrosis).
When they suspect VUR, doctors may do imaging tests Imaging Tests of the Urinary Tract There are a variety of tests that can be used in the evaluation of a suspected kidney or urinary tract disorder. (See also Overview of the Urinary Tract.) X-rays are usually not helpful in evaluating... read more to look for abnormalities of the kidneys and ureters that can cause VUR as well as any kidney damage that may have resulted. These tests may include ultrasonography, voiding cystourethrography, and radionuclide cystourethrography. If VUR has resolved but resulted in scarring, the scarring may be visible on the imaging tests.
Sometimes antibiotics to prevent infections
Children with vesicoureteral reflux (VUR) and their parents should be aware of the symptoms of urinary tract infection Overview of Urinary Tract Infections (UTIs) In healthy people, urine in the bladder is sterile—no bacteria or other infectious organisms are present. The tube that carries urine from the bladder out of the body (urethra) contains no bacteria... read more (UTI), which can vary by age. They may include fever, vomiting, burning during urination, and inability to control the bladder. If reflux is moderate or severe, children may need to take antibiotics to prevent UTIs. However, it is not clear that taking antibiotics prevents kidney damage.
Sometimes, children with severe VUR are treated with surgical procedures designed to strengthen the tissues around the ureter's opening into the bladder and thus prevent backflow of urine into the ureters.
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
American Kidney Fund, Vesicoureteral Reflux (VUR): General information on VUR, including the differences between primary and secondary VUR