Urinary Tract Infections and Reflux: Tales from NEJM
The New England Journal of Medicine features a veritable pediatric UTI festival in its July 21, 2011, issue. First Montini et al provide a Medical Progress review, highlighting the history of our understanding and treatment strategies for this common condition. Since the middle of the last century, we have recognized a link between recurrent febrile UTIs, vesicoureteral reflux, and kidney scarring. Since the 1970s such children have been subjected to repeated imaging studies, long-term antibiotic prophylaxis, and surgical procedures.
We forgot that association is not the same as causation.
Even with our aggressive intervention, the rate of permanent kidney failure attributed to reflux has not changed in any country over the past 40 years. Wide-spread use of prenatal ultrasound demonstrated abnormalities prior to infection in many of these children. We now know, from the use of animal models and in vitro studies, that abnormal ureteral budding can produce hypoplasia and dysplasia. While the role of recurrent pyelonephritis in the evolution of kidney scars cannot be denied, it is clear that scarring may occur in the absence of UTIs as well.
Earlier studies of surgical and medical intervention to prevent kidney scarring were not well-done. More recent randomized prospective studies thus far do not support the aggressive treatment approach of the past, particularly for lower grade (I, II, or III) VUR. Other studies underway may help narrow our knowledge gap further, providing important evidence that we can use to rationally treat this condition.
To illustrate the issue, the Journal then presents a case scenario of a 6-year-old girl with one documented febrile UTI and grade III reflux; three specialists then make the case for three different treatments: observation without prophylaxis, long-term antibiotic therapy, and surgical repair of the reflux. The site includes a poll to see which therapy the readership favors (my choice was in the majority at the time of this post).
Parents often find reflux confusing as they read about it online. The problem really comes down to the history. We saw an association of reflux, UTIs, and scars, and we assumed that reflux + UTIs = scars. Based on this equation, which certainly has an intuitive, intellectual appeal, generations of children got aggressive treatment. Today, we have reexamined our assumptions; many of us now recommend a less aggressive approach to the management of these related conditions.
Studies underway may change our approach even more. In the meantime, all options must be discussed with families, and treatment individualized as necessary.