Febrile UTI in Infants and Young Children

Educational Objectives

The goal of this program is to improve management of urinary tract infections (UTIs) in infants. After hearing and assimilating this program, the clinician will be better able to:

1. Assess likelihood of UTI in infants, based on age and risk factors.

2. Select appropriate screening tests for UTI based on risk.

3. Detect significant urinary tract abnormalities using imaging studies such as ultrasonography and voiding cystourethrography.

Summary

Introduction: children with fever without source (FWS) may have urinary tract infection (UTI); ≈75% of young infants with UTI have involvement of upper urinary tract (pyelonephritis); bacteremia common (15%-20%) in infants <30 days of age

American Academy of Pediatrics (AAP) guidelines from 2011: use clinical factors to determine whether risk for UTI >1% to 2%; diagnosis requires positive urinalysis (UA) and culture containing >50,000 colonies/mL; if infant appears sick or toxic and requires antibiotics, collect urine by catheterization and give antibiotics; if antibiotics not immediately required, then assess likelihood of UTI (if likelihood <2%, then testing not needed; if likelihood >2%, collect urine)

Probability of UTI: girls with FWS — risk >2% with presence of 2 additional risk factors (ie, white ethnicity, age <12 mo, body temperature >39°C) or fever lasting >2 days; boys with FWS — all uncircumcised boys have risk >2% and should be tested for UTI; circumcised boys at lower risk for UTI and must have all 3 additional risk factors; infants <3 mo of age with FWS — at high risk for UTI and should be tested; infants >3 mo of age — in girls 3 mo to 2 yr of age with FWS, risk for UTI 5% to 10%; in uncircumcised boys, rate of UTI drops significantly after 3 mo and again after 6 mo of age (UTI rare at ≈1 yr of age); UTI extremely rare in circumcised boys >3 mo of age; height of fever — higher fever (eg, ≥39° lasting >2 days) associated with greater likelihood of UTI (especially in children >3 mo of age); ethnicity — in girls, white ethnicity associated with higher risk; in boys, nonblack ethnicities associated with higher risk (even when controlled for circumcision status)

Speaker’s recommendations for testing children with FWS for UTI: 5% probability reasonable threshold, unless infant at high risk (eg, immunosuppressed, premature); infants <3 mo of age with fever >38°C for any period of time should be tested; UTI unlikely in children 3 to 24 mo of age, unless fever >39°; test girls only if fever persists >2 days; test uncircumcised boys <6 mo of age, or <12 mo of age if risk factors present; UTI rare in circumcised boys >3 mo of age (test if child appears sick and has other risk factors); catheter specimen recommended for culture

Bag-collected urine: UA — specificity of leukocyte esterase testing lower (more false positives) compared to catheter-collected urine, but sensitivity similar; negative UA of bag specimen more helpful than positive result (eg, infants at lower end of risk stratification with negative UA can be sent home); culture — gold standard; false positives can occur from contamination from, eg, perineum, diaper, bag removal, technique; false negatives depend on threshold used to determine positivity (speaker usually uses threshold of 100,000 colonies/mL; chance for false positives and negatives equal [≈15%]); predictive values of culture — with positive culture, probability increases from 5% to 23% in child with low prior probability (eg, older circumcised boy with fever for 1.5 days); negative predictive value <1%; in child with moderate prior probability, higher positive and slightly higher negative predictive values; in child with high prior probability, positive predictive value 60% (negative predictive value 4%); conclusions — in low-probability children, negative culture of bag specimen confidently rules out UTI (positive culture suggests 25% chance of having UTI [treatment with antibiotics for few days reasonable]); in high-probability children, negative bag culture does not rule out UTI with sufficient certainty

Testing: high-risk infants — eg, infants <6 mo of age, with systemic illness, or with history of 2 previous UTIs (requiring referral to urologist); obtain catheter specimen; if UA positive, treat for UTI; low- or moderate-risk infants — eg, infants >6 mo of age who appear well, with (perhaps) first UTI; perform bag collection; if UA negative, no further work-up required; if UA positive, options include collecting urine by catheterization for culture or sending bag specimen for culture (perform catheterization if significant downsides of false positives or negatives exist)

Action statement from AAP: positive UA and culture of ≥50,000 colonies/mL required for UTI; assumptions — 1) chance of negative leukocyte esterase and true UTI very low; false negatives tend to occur in patients who have either false-positive culture or asymptomatic bacteriuria (not true UTI); concluded that true sensitivity of leukocyte esterase higher (negative result confidently rules out UTI); 2) diagnosing asymptomatic bacteriuria (ie, urine culture positive but would clear spontaneously) as UTI does more harm than good; prioritizes benefits of not overtreating over the possible harm of missing UTI; speaker feels assumptions do not hold for very young infants or infants at high risk for complications from UTI

Speaker’s recommendations: high-risk children — collect catheter specimen for UA and obtain culture; >10,000 colonies/mL in clean catheter specimen considered positive; low- or moderate-children — urine collection by bag or catheter acceptable; if UA negative, no further work-up required; if UA positive, choose between sending bag specimen for culture, or collecting catheter specimen for culture; bag specimen should be clean, and high threshold should be used to minimize false positives

Treatment of febrile UTI in children: know local microbiology and sensitivities; Escherichia coli common cause and sensitive to first-generation cephalosporins (eg, cephalexin); evidence suggests oral antibiotics sufficient for most infants; treat infants <2 mo of age and older infants not sufficiently taking oral antibiotics with intravenous (IV) antibiotics; give first dose IV or intramuscularly and let parents pick up oral course (10 days sufficient)

Imaging studies: ultrasonography (US) at earliest convenience recommended for all infants with first-time febrile UTI (more urgently if infant not responding well to treatment); voiding cystourethrography (VCUG) only if US abnormal or if infant presents with second UTI; prophylactic antibiotics not recommended; goals of imaging studies after first UTI — find any significant urinary tract abnormalities (eg, duplicated ureter, urinary tract obstruction); prevent recurrent UTI and damage to kidneys

Posterior urethral valve: most identified on prenatal US; manifestations — grossly enlarged kidneys; distended bladder; failure to thrive and poor growth; systemic illness; may present with urosepsis; presents early with severe complications; 15% to 20% progress to end-stage renal disease

Vesicoureteral reflux (VUR): retrograde flow of urine up to ureters or kidneys during voiding; most common urinary tract abnormality in children; 50% of infants <3 yr of age with first UTI have some degree of reflux; most cases low grade; grade I — reflux into ureter; grade II — reflux into kidney; grade III — some dilation; grade IV — gross dilation, including renal calyces; 95% of VUR (30%-50% in children) grades I, II, or III; grades IV and V rare in children with first-time UTI, but occur in children with end-stage renal disease or complications from UTI

Options for imaging: US — operator dependent; useful for obstruction, growth abnormalities, and high-grade reflux (sensitivity ≈85%); in relatively low-risk patient, normal US reassuring (no follow-up VCUG required); VCUG — difficult to perform; traumatic for infants and families; high radiation; more sensitive and specific; test of choice for posterior urethral valves

Effects of VUR: no difference in risk for recurrence of UTI between children with or without reflux; renal scarring — more likely in infants with high-grade (grade IV or V) VUR and recurrent UTIs; however, not related to number or severity of UTIs or presence or absence of VUR; tends to be nonprogressive and likely represents damage that occurred prenatally; end-stage renal disease — rare; 5% to 12% of infants and children with end-stage renal disease have history of reflux nephropathy; risk for development after first episode of pyelonephritis extremely low

Prophylactic antibiotics: no effect on scarring, compared to surgical repair of reflux (Cochrane review saw similar rates of recurrent UTI); no significant effect on UTI recurrence or renal scarring in children with first-time UTI (with or without reflux); several studies show trend toward more UTIs and predominance of more resistant organisms with use of antibiotics

Identifying reflux and severe abnormalities: retrospective review found no change in UTI recurrence or detection of high-grade VUR after enactment of more selective imaging policy, but amount of imaging studies and use of prophylactic antibiotics decreased; other study of 400 children with first-time UTI using selective imaging strategy (ie, VCUG after abnormal US) found that only 7% of children had abnormal US, and 13% of those had scarring (concluded that selective imaging strategy does not impair ability to find significant abnormalities); AAP action statement states that VCUG should not be performed routinely, but may be considered after abnormal US or recurrent UTI; US — speaker recommends after first UTI in infants <3 mo of age, and for infants >3 mo of age who have recurrent UTI; US for infants who do not respond well to treatment or remain febrile after 48 hr; VCUG — indicated in infants with evidence of significant obstruction of urinary tract; consider in infants with recurrent UTI and reflux on US only when possible correction of reflux warranted

Summary: consider pyelonephritis or UTI in all infants <2 yr of age with FWS; consider testing for UTI if prior probability >5% or risk for severe infection high (includes infants <3 mo of age regardless of sex or circumcision status); in infants 3 to 24 mo of age, consider circumcision status and clinical factors (eg, height and duration of fever); imaging studies — perform US in cases of complicated or recurrent UTI; consider after first UTI in high-risk infant or infant <3 mo of age; consider VCUG if findings would change management; antibiotics not recommended for prevention of recurrent UTIs or renal scarring even in patients with known or suspected reflux

Readings

No authors listed: Imaging after a first febrile UTI in infants and children: less is more? J Paediatr Child Health. 2012 Oct;48(10):945; Alexander DS et al: The association between recreational parks, facilities and childhood obesity: a cross-sectional study of the 2007 National Survey of Children’s Health. J Epidemiol Community Health. 2013 Jan 30. [Epub ahead of print]; Casazza K et al: Myths, presumptions, and facts about obesity. N Engl J Med. 2013 Jan 31;368(5):446-54; Copeland KC et al: Management of Newly Diagnosed Type 2 Diabetes Mellitus (T2DM) in Children and Adolescents. Pediatrics. 2013 Feb;131(2):364-82; Edmonds EW, Templeton KJ: Childhood Obesity and Musculoskeletal Problems: Editorial Comment. Clin Orthop Relat Res. 2013 Jan 26 [Epub ahead of print]; Hunziker M et al: Incidence of febrile urinary tract infections in children after successful endoscopic treatment of vesicoureteral reflux: a long-term follow-up. J Pediatr. 2012 Jun;160(6):1015-20; Katz DL: Childhood obesity trends in 2013: mind, matter, and message. Child Obes. 2013 Feb;9(1):1-2; Lee JH et al: Is a routine voiding cystourethrogram necessary in children after the first febrile urinary tract infection? Acta Paediatr. 2012 Mar;101(3):e105-9; Nemet D et al: Effects of a combined intervention for treating severely obese prepubertal children. J Pediatr Endocrinol Metab. 2013;26(1-2):91-6; Pennesi M et al: Managing children under 36 months of age with febrile urinary tract infection: a new approach. Pediatr Nephrol. 2012 Apr;27(4):611-5; Roberts KB: Revised AAP Guideline on UTI in Febrile Infants and Young Children. Am Fam Physician. 2012 Nov 15;86(10):940-6; Subcommittee on Urinary Tract Infection, Steering Committee on Quality Improvement and Management, Roberts KB: Urinary tract infection: clinical practice guideline for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months. Pediatrics. 2011 Sep;128(3):595-610; Sharifi M et al: Evaluating the implementation of expert committee recommendations for obesity assessment. Clin Pediatr (Phila). 2013 Feb;52(2):131-8; Tullus K: What do the latest guidelines tell us about UTIs in children under 2 years of age. Pediatr Nephrol. 2012 Apr;27(4):509-11; Young RP, Hopkins RJ: Genetic risk in childhood obesity: implications for clinical practice. JAMA Pediatr. 2013 Feb 1;167(2):196-8.

Disclosures

In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, the faculty and planning committee reported nothing to disclose.

Acknowledgements

Dr. Marmor spoke in San Francisco, CA, at Annual Review in Family Medicine: Controversies and Challenges in Primary Care, presented December 3-4, 2012, by University of California, San Francisco, School of Medicine. Visit www.cme.ucsf.edu/cme/ for information about upcoming courses from this sponsor. The Audio-Digest Foundation thanks the speaker and the UCSF School of Medicine for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

FP611401

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.

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