New York: Most children with recurrent urinary tract infections (UTIs) are not at increased risk of chronic kidney disease later in life, a new study suggests.
"If there is no structural abnormalities in the kidney ultrasound after the first UTI, the parents should not be worried at all" about the risk of chronic kidney disease, said lead researcher Dr. Jarmo Salo of the University of Oulu in Finland.
Recurrent UTIs in young children have been seen as a possible risk factor for chronic kidney disease later in life. That`s especially true if a child has what`s called vesicoureteral reflux, or VUR.
About 1 percent of children have VUR, where some urine backs up from the bladder into the kidneys. The reflux itself does not damage the kidneys, but because bacteria in the urine can get into the kidneys, these children are more prone to kidney infections that can lead to scarring.
But the idea that repeat UTIs and VUR are risk factors for chronic kidney disease later in life is not universally accepted -- nor is the practice of testing children for VUR when they have a urinary tract infection.
So for the new study, reported in the journal Pediatrics, researchers in Finland combed the medical literature to look for evidence that childhood UTIs are a risk factor for chronic kidney disease.
They also reviewed the records of all 366 patients who were treated for chronic kidney disease at their hospital over one year.
The team found 10 published reports that either looked at the history of childhood UTIs in people with chronic kidney disease, or that followed children with UTIs to see how their kidney health fared.
Among the 1,576 patients in those studies, there was no evidence that childhood UTIs -- even along with VUR -- were the main cause of chronic kidney disease, according to the researchers.
And of the kidney disease patients who did have a history of childhood UTIs, all also had structural abnormalities in their kidneys. Similarly, of the 366 patients at their center, the researchers found that only three had repeat childhood UTIs that might have contributed to their chronic kidney disease -- and all had structural abnormalities in the kidneys.
Such structural abnormalities -- problems like an obstruction in the kidneys -- can be picked up by an ultrasound when a young child is diagnosed with a UTI.
But Salo told Reuters Health in an email that the findings suggest that kids with VUR are at no increased risk of kidney disease, as long as there are no structural abnormalities in the kidneys.
NO LONGER LOOKING IN FINLAND
When VUR is diagnosed, it is usually because doctors specifically look for it in a young child with a UTI. That takes a special test called a cystogram, where a catheter is placed in the bladder and the bladder is filled with fluid. X-rays allow the doctor to see if the fluids back up into the kidneys.
Salo said doctors in Finland no longer "actively" look for VUR because there`s evidence that it is a "normal phenomenon," and that treating it does not prevent long-term kidney damage.
"We suggest that the (x-ray) imaging studies are not necessary if the child has structurally normal kidneys in ultrasound," Salo said.
But a pediatric urologist not involved in the study cautioned against making a "sweeping" recommendation against VUR testing.
"The good news for parents is yes, the chances of your child developing kidney disease will be very low," said Dr. Hiep T. Nguyen of Children`s Hospital Boston.
However, he told Reuters Health, repeat UTIs in young children (generally younger than 5) are not the same as those in older kids or adults. And some of those children are at increased risk for kidney damage -- particularly if they have more-severe, "high-grade" VUR.
What`s more, Nguyen said, there is evidence that finding and treating high-grade VUR may prevent kidney damage. Treatment involves low doses of antibiotics to prevent repeat UTIs and periodic testing to see if the reflux has gone away. Some children with severe VUR end up having surgery to correct the problem if they keep getting infections.
Mild reflux typically goes away on its own -- though, in North American, doctors still prescribe low-dose antibiotics to prevent the UTIs.
Nguyen said that a young child with a UTI should have an ultrasound "at a minimum" to look for structural abnormalities in the kidneys. Salo agreed.
SHOULD DOCTORS TEST?
But the area of controversy is in testing for VUR. Essentially, Nguyen said, pediatricians are increasingly moving away from recommending VUR testing for children with urinary tract infections.
Pediatricians, he noted, see a lot of children with UTIs, and most of those kids will have no long-term kidney disease as a result. But urology specialists see the people with chronic kidney disease, and they are apt to see the value in testing for VUR so that kids with reflux can be treated.
"We are looking from two different viewpoints," Nguyen said.
VUR has a strong genetic component, and researchers are working on gene tests -- where a child will just have to "spit in a cup," Nguyen said -- that could help pinpoint the kids with UTIs who would be the best candidates for VUR testing.
For now, the decision to do VUR testing is basically case-by-case.
Dr. John Gearhart, director of pediatric urology at Johns Hopkins Children`s Center in Baltimore, said the current findings "should reassure mothers and fathers."
But he agreed that there are cases where testing for VUR is appropriate: if there`s a family history of the condition, for example, or if a young child has more than one urinary infection that includes fever.
Testing for VUR does involve radiation, albeit as low a dose as possible, Gearhart noted in an interview. So limiting the number of children who have it is important.
There can also be side effects from the low-dose antibiotics given to children with VUR -- such as stomach upset, diarrhea and yeast infections.
There is an ongoing North American clinical trial looking at whether giving antibiotics to young children with mild to moderate VUR prevents kidney scarring (which, down the line, might contribute to chronic kidney disease).
That, according to Gearhart, should give more insights into whether it is helpful to give all children with VUR preventive antibiotics.