Diagnosis and Management of UTI in Febrile Infants Age 0–2 Months: Applicability of the AAP Guideline
Urinary tract infections (UTIs) are the most common bacterial infection in young infants. The American Academy of Pediatrics’ (AAP) clinical practice guideline for UTIs focuses on febrile children age 2-24 months, with no guideline for infants <2 months of age, an age group commonly encountered by pediatric hospitalists. In this review, we assess the applicability of the AAP UTI Guideline’s action statements for previously healthy, febrile infants <2 months of age. We also discuss additional considerations in this age group, including concurrent bacteremia and routine testing for meningitis.
© 2020 Society of Hospital Medicine
SPECIAL CONSIDERATIONS
Bacteremic UTI
The prevalence of bacteremia in infants ≤60 days old with UTIs was 9% in a study conducted from 2008 to 2013 in 26 EDs and has ranged from 3% to 17% in older studies.10, 22 Many studies have described similar clinical and laboratory findings in young infants with bacteremic and nonbacteremic UTIs.39-41 Despite this, bacteremic UTIs have been associated with prolonged parenteral antibiotic courses, resulting in longer hospitalizations and increased costs.40 Two recent multicenter studies of infants with bacteremic UTIs (251 infants <3 months old22 and 115 infants ≤60 days old42) demonstrated variable IV courses and no association between IV duration and relapsed UTI. The latter study showed no risk difference in the adjusted 30-day UTI recurrence (risk difference 3%, 95% CI: −5.8 to 12.7) or all-cause reutilization (risk difference 3%, 95% CI: −14.5 to 20.6) between long and short IV groups.42 Neither study had patients with relapsed bacteremic UTIs or reported that patients suffered clinical deterioration while on oral antibiotics.22,42
Based on these data demonstrating that adverse outcomes are rare in infants with bacteremic UTIs and not associated with parenteral antibiotic duration, we recommend short parenteral courses (2-3 days) with conversion to oral therapy once infants have clinically improved.
Positive Urinalysis and Testing for Meningitis
Multiple risk stratification algorithms for febrile infants aged ≤60 days categorize infants with a positive UA (and therefore likely UTI) as high-risk for having concomitant bacteremia or meningitis, for which lumbar puncture (LP) is typically recommended.43-45 The risk of not testing CSF is the potential to insufficiently treat meningitis because treatment for UTIs and meningitis differ in dosing, route, and duration. Recent studies have challenged the practice of routine LPs for infants aged 1-2 months with a suspected UTI due to the low prevalence (0%-0.3%) of concomitant meningitis.39,46-48 A meta-analysis of 20 studies reporting rates of concomitant meningitis with UTI in infants aged 29-90 days found a pooled prevalence of 0.25% (95% CI: 0.09%-0.70%).49 Furthermore, a study of febrile infants ages 29-60 days found that the prevalence of meningitis did not differ between those with a positive vs negative UA (3/337 [0.9%] vs 5/498 [1.0%], respectively), suggesting that a positive UA alone should not modify the pretest probability of meningitis in this age group.50
Two studies have also examined the risk of delayed meningitis among infants ≤60 days old treated for UTIs without CSF testing. A northern California study that examined 345 episodes among 341 UA-positive infants aged 29-60 days found zero cases (95% CI: 0%-1.1%) of delayed meningitis within 30 days of evaluation.50 A multicenter study of well-appearing febrile infants aged 7-60 days found 0/505 cases (95% CI: 0%-0.6%) of delayed meningitis within 7 days of discharge; 407 (81%) were aged 31-60 days.51 In summary, studies have shown a low rate of concomitant meningitis and a low risk of delayed meningitis in infants aged 1-2 months treated for UTI without CSF testing. Given this, clinically targeted (eg, based on ill appearance and/or lethargy), rather than routine, CSF testing in this age group can be considered.
