“Of course, a lot of sites are not doing DMSA [dimercaptosuccinic acid] renal flow scans up front, so they don't know whether there is scarring, but these recommendations stem from an empirical treatment model that's been in place for 20–30 years that suggests UTIs in the presence of reflux leads to scarring which can lead later in life to end-stage renal disease, hypertension, or preeclampsia in young women,” he said. “The idea was that if you could knock out either one of these arms—UTI or VUR—either by surgically correcting the reflux or preventing UTI with prophylactic antibiotics, you could prevent the march down this path.”
Multiple studies comparing the effectiveness of these interventions have failed to show that either approach is better than the other with respect to the development of new renal scars, “or whether any intervention does more good than harm for VUR,” said Dr. Keren.
Because of this, “there is a lot of skepticism about that empirical model as the basis for our management, which has led to calls for a 'top down' management approach, starting with the kidneys vs. the bladder.”
According to this approach, the kidneys of children with a UTI should be assessed by DMSA scan. “The absence of abnormalities on DMSA scan has a very good negative predictive value for high-grade VUR, which is most strongly associated with subsequent renal scarring and other effects of pyelonephritis,” said Dr. Keren. “With normal DMSA scan, you can reassure parents that the kidneys are normal and that the child is unlikely to have dilating VUR, and you might want to consider skipping the VCUG.” An abnormal scan warrants the VCUG and, depending on the degree of VUR, the consideration of antibiotics or surgery, he said.
Dr. Keren reported having no financial conflicts of interest with respect to his presentation.
Dysfunctional Voiding Often Causes UTIs
It's critical for general pediatricians to consider dysfunctional elimination as a cause of urinary tract infections in children, Dr. Keren said.
Dysfunctional elimination often goes undiagnosed and undertreated, despite the fact that approximately 40% of children with first UTI and 80% of children with recurrent UTI will have symptoms of the condition, Dr. Keren said. It is characterized by abnormal elimination patterns (frequent or infrequent voids, urgency, and constipation), bladder or bowel incontinence, and/or withholding maneuvers.
The possibility of dysfunctional elimination can be evaluated using the validated Dysfunctional Voiding Scoring System, which asks a series of simple questions about bowel and bladder practices (J. Urol. 2000;164:1011–5).
Once the condition has been diagnosed, parents should be encouraged to try some simple interventions, such as scheduling voiding times every 2 or 3 hours, treating constipation with laxatives and increased fluid intake, and avoiding bladder irritants such as caffeine, food coloring, chocolate, citrus, and carbonated beverages.
“If these interventions don't work, I would refer the child to a urologist for further evaluation. Often, some of the bigger academic hospitals will have dysfunctional voiding clinics, where a psychologist might work with the child using biofeedback to retrain the pelvic floor muscles. The urologist might also prescribe anticholinergics,” Dr. Keren said.
Studies have shown treatment of dysfunctional elimination can decrease UTI recurrences and can speed the resolution of VUR, he said. As such, “screening for [dysfunctional elimination] is an important first step in the management of pediatric UTI,” he said.