Urinary tract infection in febrile infants

August 1, 2012

AAP recommendations for diagnosing and managing a first urinary tract infection in children aged 2 to 24 months were updated in 2011.

Key Points

In 1999, the American Academy of Pediatrics (AAP) released the practice parameter "The Diagnosis, Treatment, and Evaluation of the Initial Urinary Tract Infection in Febrile Infants and Young Children."1 The topic was selected years before by the AAP chapter chairs as a topic about which pediatricians desired guidance. Although the AAP routinely reviews and revises as necessary its clinical practice guidelines, the revision of this particular guideline proved to be anything but routine.

As the process got under way, evidence began to emerge that challenged previous recommendations and even the basic thinking that had been in place for decades about the management of urinary tract infections (UTIs) in infants. The subcommittee charged with updating the guideline published the revision in 2011, recommending changes in diagnostic criteria, treatment, imaging strategy, and follow-up.2 A companion technical report provided additional detail about the evidence base for the recommendations.3

The revision addresses the diagnosis and management of a first UTI in infants aged 2 to 24 months who have unexplained fever; infants with neurologic or anatomic abnormalities known to be associated with UTIs and/or renal damage are excluded. Questions have arisen during various presentations of the guideline, which are offered here in the order in which they might come up for clinicians caring for a febrile infant and the same order they are addressed in the guideline. (Unless otherwise noted, all information is supported through references found in the published guideline and technical report.)

A. This is a common-and important-question, not only in pediatricians' offices but also in emergency departments, acute care clinics, and the offices of family physicians. When an antibiotic is going to be administered to an infant whose fever is unexplained, it is strongly recommended that a urine specimen be obtained before the antibiotic is administered. The antibiotics commonly prescribed in this situation obscure the presence of a UTI after the first day and make it difficult for the clinician to establish a diagnosis and determine the duration of treatment. Although VCUG is not recommended routinely after the first UTI, a renal-bladder ultrasonogram (RBUS) is recommended, and a VCUG would be considered if the RBUS demonstrates dilatation; moreover, a VCUG would be considered after a second febrile UTI, so it is important to identify the first.

The frequency with which urine collected in a bag is contaminated makes this method of collection inappropriate in situations in which an antibiotic is about to be administered. Not only are the results of the culture likely to be falsely positive, the time required for the infant to void delays the administration of the antibiotic.

Q. If my clinical judgment is that an antibiotic is not warranted right away, can I just watch and wait-or do I need to obtain a urine specimen from every febrile infant without an obvious source, even if the child appears well, has a low-grade fever, and has only been ill for a short time?