Tuesday, October 18, 2011

Pediatric UTI: Putting the Guidelines Into Practice

From Medscape Pediatrics An Expert Interview With S. Maria Finnell, MD Laurie Scudder, DNP, PNP; S. Maria Finnell, MD, MS 10/05/2011 Editor's Note: The American Academy of Pediatrics (AAP) has recently published an updated Clinical Practice Guideline and technical report addressing the diagnosis and management of an initial urinary tract infection (UTI) in febrile infants and young children. This document updates the previous guidelines published in 1999 and makes several new recommendations based on more recent research. Laurie Scudder, DNP, PNP, spoke with S. Maria E. Finnell, MD, MS, who coauthored the Technical Report. Dr. Finnell is an assistant professor in the School of Medicine at Indiana University and a physician with the Pediatric Infectious Disease Division at the Riley Hospital for Children. Medscape: The new guideline recommends selective urine testing in febrile infants between 2 and 24 months of age based on the prior probability of UTI in that child. Several factors that increase risk are identified and the guideline makes different recommendations for low-risk and high-risk infants. Could you expand on this? S. Maria Finnell, MD: There are certain clinical findings that can help clinicians identify children at very low risk for UTI. The benefit of identifying these very low-risk children is that these children can be observed and do not need initial testing. High-risk children are identified based on the number of risk factors, and these factors differ somewhat between boys and girls. How many risk factors a particular child has is the important point here. In the original studies, some risk factors were identified as being stronger than others. For boys, circumcision status definitely matters the most. Uncircumcised boys have a greater risk for UTI than circumcised boys. For girls, non-black race appears to be the risk factor that carries the most weight. Probability of UTI among febrile infant girls and infant boys according to number of findings present. A probability of UTI exceeds 1% even with no risk factors other than being uncircumcised. From Subcommittee on Urinary Tract Infection and Steering Committee on Quality Improvement and Management. Urinary tract infection. Pediatrics. 2011; 28:595-610. Medscape: The guideline emphasizes the importance of collecting an acceptable urine sample for urinalysis and culture prior to initiating antimicrobial therapy. The risk for suprapubic aspiration is also discussed, although it is noted that in some circumstances, such as boys with severe phimosis, this may be the only option for obtaining a urine specimen. Is there any role for noninvasive collection strategies such as use of a bag applied to the perineum? Dr. Finnell: Yes. It is important to point out that bag specimens are acceptable if they are going to be used for urinalysis. However, a bag specimen cannot be used to culture the urine because contamination from skin, the vagina in girls, or the prepuce in uncircumcised boys leads to false positive results too often. If the urinalysis from a bag specimen is positive, then the culture needs to be obtained by catheterization. So you can use bag specimens, but only for the urinalysis. To obtain a urine culture from the child and confirm the diagnosis of UTI, that specimen needs to be from a catheterization. When it is not possible to catheterize the child, as in the example that you mentioned, then we recommend suprapubic aspiration. Medscape: The guideline notes that a diagnosis of UTI requires the presence of both a quantitative urine culture and evidence of pyuria. Pyuria is defined as the presence of white blood cells noted by means of microscopic analysis. However, use of a leukocyte esterase test is also discussed. Is leukocyte esterase testing an acceptable alternative to microscopic analysis? Dr. Finnell: Yes. Leukocyte esterase on a dipstick is an acceptable surrogate marker for pyuria. It is not, as described in the technical report, as specific as either bacteria or white blood cells found on microscopy, but together, a positive urine culture and a positive leukocyte esterase is an acceptable way of diagnosing UTI. Medscape: Would the reverse -- a negative leukocyte esterase test in a child -- be an acceptable reason not to proceed to culture? Dr. Finnell: On a dipstick, if either leukocyte esterase or nitrite is positive, a culture should be obtained. If neither is positive, the clinician can follow the clinical course. For a urinalysis, either presence of white cells above the threshold of normal for the test used or the presence of bacteria should motivate a culture. If neither is present, the clinician can choose to follow the clinical course. It is important to point out that the specimen must be fresh (< 1 hour after voiding in room temperature, < 4 hours after voiding if stored in a refrigerator) to be able to make these decisions based on these tests. If the initial testing is negative (urinalysis or dipstick), the clinician should follow the child's clinical course and reevaluate if fever persists. These recommendations are well illustrated in the algorithm that accompanies the guideline (Figure 2). Medscape: The guideline recommends that regional variation in antimicrobial susceptibility patterns dictate the choice of initial treatment. In situations where this information may not be readily available, are there other considerations that should dictate the choice of therapy, including the route of administration? Dr. Finnell: The guideline does list the antibiotic options for initial treatment of UTI. As always, that treatment decision has to be tailored to the patient in front of the clinician. So, for example, allergies, dosing frequency, and how adherent the parents are anticipated to be are going to be important when choosing both the initial antibiotic treatment as well as the route of administration of the antibiotic. I think it is worthwhile to point out that recent studies have found that oral therapy is as effective as parenteral therapy. However, children who are too ill to take medication orally or who cannot tolerate medication by mouth for any other reason should be treated with antibiotics parenterally. Medscape: Renal and bladder ultrasonography (RBUS) is recommended as the initial imaging test, although the guideline notes the potential for misleading results if RBUS is obtained too early in the acute infection. If not in the acute course, when should this type of imaging be performed? Dr. Finnell: Ultrasonography is ideally performed after full recovery and completion of the antibiotic course. That means a minimum of 2 weeks after diagnosis, and sometimes longer. There are, though, some exceptions to consider. First, RBUS is an excellent tool to identify renal abscesses in children who do not respond to therapy as expected. In those cases, the ultrasound would be done earlier in the course. Secondly, RBUS may also need to be performed earlier if there are concerns that the parents may not return with the child for imaging once the child has improved. Medscape: One of the most notable differences from the 1999 guideline is the recommendation that a voiding cystourethrogram (VCUG) should not be routinely performed after a first febrile UTI. Can you explain the basis for this change of recommendation? Dr. Finnell: The 1999 guideline recommended the VCUG after first UTI for children who were between 2 and 24 months of age. The rationale for that recommendation was that it was thought that children with vesicoureteral reflux (VUR) could be treated with prophylactic antibiotics to reduce further episodes of UTI. However, since the 1999 guideline was published, there have been 6 published randomized controlled trials that have examined the effects of antibiotic prophylaxis in preventing recurrent UTIs. Meta-analyses of these results performed for the technical report that accompanies this guideline do not support the contention that antibiotic prophylaxis prevents febrile UTI when VUR is found through VCUG. Because it wouldn't change the treatment, it can no longer be justified to put all children through a VCUG after a first episode of UTI. Medscape: There is no longer a recommendation for use of prophylactic antibiotics to prevent UTI recurrences because, as you just discussed, the meta-analyses have revealed no significant reduction in symptomatic UTI with prophylaxis, even for those infants with grade 3 or 4 VUR. Are there any situations where prophylaxis should be considered? Dr. Finnell: I think it is important to note that we know now that the vast majority of young children with the first UTI will not benefit from prophylactic antibiotics. However, there may be a few children who have recurrent UTI or really high-grade VUR who may benefit. Those potential benefits to these children have not been tested in the clinical trials we have seen to date. There were very few children with really high-grade reflux enrolled, so these situations are unusual and have not been well studied. When there are no good studies, we are going to have to rely on our best clinical judgment on a case-by-case basis. Providers are going to have to make their call on what to do for these children. Medscape: Is there a comparable role for clinical judgment in making the decision to test children for subsequent UTIs? For example, consider the case of a toddler who has a documented UTI and 2 months later, when both older siblings have febrile upper respiratory tract infections, presents with a fever. Should that child still be tested for recurrent UTI even though the clinical suspicion is that the fever is more likely to be the result of a cold than a second UTI? Dr. Finnell: In general, the clinician should always be more suspicious of UTI in a child who has already had one documented UTI. Saying that, you have to take the clinical picture into consideration. If there is another source for the fever, the risk for UTI is going to go way down. We do not recommend automatic testing every time this child has a fever, but we do recommend contact with medical care and an evaluation. The importance of this needs to be communicated to the parents of children with documented UTI. Medscape: How long should that elevated level of suspicion persist. Is it important to test more often until the child is 4 or 5 years of age and able to provide a history of what hurts? Dr. Finnell: One reason why UTI is such a tricky diagnosis in very young children is that they can't express their concerns. As the child grows older, you can take your guard down a little bit. However, an elevated level of suspicion for UTI and a low threshold for evaluation should persist throughout childhood. Medscape: Dr. Finnell, are there other key recommendations or important points in this new guideline that you would like to emphasize? Dr. Finnell: Yes. There are some data to suggest that early treatment of UTI may decrease the risk for renal damage. Therefore we recommend early evaluation, within 24 to 48 hours, in the case of fever in children who have previously been diagnosed with a UTI. When these children have the next fever, they should be seen early, evaluated and, if indicated, tested for UTI with the goal of preventing future renal damage. I would also like to point out that these 2 AAP publications in Pediatrics offer the most current and comprehensive evidence available on the topic of UTI in children 2-24 months of age. These AAP recommendations are going to influence care not only in the United States, but around the world.

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