Urinary Tract Infection (UTI) in Children

Background

• UTIs are infections of the urinary bladder and/or kidney and are sometimes associated with an infection of the blood stream (urosepsis).
• A UTI is more common in uncircumcised boys in the first 6 months of life and then becomes more common in girls after age 6 months.
• Other risk factors include urethral obstruction, posterior urethral valves, dysfunctional elimination syndrome (bowel/bladder dysfunction), diabetes mellitus, urinary tract catheter or instrumentation, urological surgery, a fistula between the urinary tract and the gastrointestinal tract or vagina, and vesicoureteral reflux.
• Monomicrobial bacterial infection is found in > 95% of UTIs.
  • It is usually due to Escherichia coli or Klebsiella.
  • Other organisms include other gram-negative bacilli, gram-negative cocci, gram-positive cocci, and Chlamydia trachomatis.
  • The prevalence of individual bacteria may vary by demographics.

Evaluation

• Aged 0-36 months:
  • Newborns in the first 1-2 weeks of life with UTI most often present with temperature instability, hypothermia, and/or tachypnea. After the first 2 weeks of life, presentation may include irritability and lethargy, fever, vomiting, jaundice (if < 8 weeks old), sepsis, or failure to thrive.
  • Test for occult serious bacterial infection (including UTI) in all children in this age range based on age and height of fever at time of presentation.
    • As part of this screen for occult serious bacterial infection, test urine with urinalysis and urine culture if < 3 months old and presenting with an unexplained temperature ≥ 38 degrees C (100.4 degrees F).
    • If between ages 3 and 36 months, an unexplained temperature that is ≥ 39 degrees C (102.2 degrees F) is one of several important risk factors for possible occult UTI, among other risk factors including gender, ethnicity, circumcision status, and/or a prior history of UTI.
    • See Fever Without Apparent Source in Infants and Young Children for details.
• > 3 years old:
  • Preschool and school-aged children usually present with the classic symptoms of dysuria, frequency, and urgency, with or without fever.
  • Test urine for infection in all children > 3 years old if the child presents with signs and symptoms of a UTI.
• Urine should be collected by clean catch, catheter, or suprapubic aspiration.
  • The specimen should be obtained before giving antibiotics (Strong recommendation).
  • If a high-quality clean-catch midstream urine sample cannot be obtained:
    • collect catheter or suprapubic aspiration specimen for culture and urinalysis (Strong recommendation)
    • if there is a low clinical suspicion of UTI, consider a convenient specimen for urinalysis followed by an appropriate specimen for culture if urinalysis is suggestive of UTI
    • consider doing only urine culture if there is limited volume of urine from a catheter or suprapubic aspiration specimen, especially in infants
• A blood culture should be drawn in children with a toxic appearance and dehydration or a severe UTI.
• C-reactive protein, but not a peripheral white blood cell count, may help differentiate an upper (pyelonephritis) from a lower tract infection.
• Combinations of age, gender, clinical features, and urine dipstick results may be used to predict the probability of UTI in children.
• Diagnose UTI in a child with consistent clinical findings and a positive urine culture from an age-appropriate urine sample.
• Imaging studies may be indicated to assess for structural anomalies, vesicoureteral reflux, dysfunctional voiding, or other conditions requiring further evaluation and treatment. Recommendations on indications, procedure, and timing vary.
  • Perform renal and bladder ultrasound to exclude obstruction of upper and lower urinary tract in infants with febrile UTI (Strong recommendation).
  • Perform renal and bladder ultrasound for children with complicated UTI.
  • Recommendations from professional organizations regarding the use of voiding cystourethrography differ in specifics, but this imaging modality is not routinely recommended after the first febrile UTI.
  • Consider these imaging studies in other children for recurrent UTI.

Management

• For any presumed urinary tract infection (UTI), obtain a urine culture and start empiric antibiotics based on local antimicrobial sensitivity patterns, if available, and adjust based on sensitivity testing of the pathogen (Strong recommendation).
• Oral antibiotics can be used for most children with UTI, including acute pyelonephritis.
• IV antibiotics are indicated for infants < 30 days, children unable to tolerate oral treatment, poor response to oral treatment, or severe illness with vomiting and dehydration (Strong recommendation).
• The choice of empiric antibiotic varies among guidelines but all guidelines include oral options of cefixime 8 mg/kg/day, cephalexin 50-100 mg/kg/day in 4 divided doses, or trimethoprim/sulfamethoxazole with trimethoprim dose 3-5 mg/kg twice daily.
• Antibiotics should be given for 5-14 days for a simple UTI, 7-14 days for febrile UTI in infants and children aged 2-24 months, or 10-14 days for a severe UTI.