Urinary Tract Infection in Children

See Also

Urinary Tract Infection

Epidemiology

UTI Incidence
1. Newborns
  1. Overall: 0.14%
  2. Febrile newborns: 7%
    1. Most common serious Bacterial Infection in children <3 months old
2. Symptomatic UTI under age 6 years
  1. Girls: 7%
  2. Boys: 2%
  3. Recurrence rate: 30%
3. School aged children: 1-2%
4. Ages 7 to 11 year old females: 2.5%
Vesicoureteral Reflux (VUR) Incidence
1. School aged children with UTI: 25-40%
2. Preschool sibling of child with VUR: 25-33%
3. Child of parent with VUR: 65%

Causes (single organism in most cases)

Bacteria
1. Escherichia coli (up to 85% of UTIs in children)
2. Klebsiella
3. Proteus (boys and associated with Nephrolithiasis)
4. Enterobacter
5. Citrobacter
6. Enterococcus
7. Pseudomonas
8. Staphylococcus saprophyticus
9. Coagulase negative Staphylococcus
Viral
1. Adenovirus (hemorrhagic cystitis)
Atypical causes
1. Fungal
2. Mycobacterium
3. Schistosomiasis

Risk Factors
Decision to evaluate for UTI

Infants under age 2 months
1. Age under 2 months is excluded from this guideline
2. See Neonatal Sepsis guidelines
Infants and children age 2 to 24 months (with fever >38 C)
1. Urinary Tract Infection is responsible for 7-15% of fever in infants
2. Risk factors for girls (<2 is reassuring and indicates a risk <1%)
  1. White race
  2. Age under 12 months
  3. Fever 39 C or higher
  4. Fever lasting more than 48 hours
  5. Absence of other source of infection
3. Risk Factors for circumcised boys (<3 is reassuring and indicates a risk <1%)
  1. Non-black race
  2. Age under 6 months
  3. Fever 39 C or higher
  4. Fever lasting more than 24 hours
  5. Absence of other source of infection
4. Risk Factor for uncircumcised boys
  1. Uncircumcised boys have a risk >1% even in absence of other risk factors
  2. Male uncircumsized infants have a higher risk of Urinary Tract Infection than girls
5. References
Children over age 2 years
1. Typical Urinary Tract Infection symptoms
2. Constipation
3. Encopresis
4. Bladder instability
5. Infrequent voiding
6. Koff (1998) J Urol 160:1019-22 [PubMed]

Findings
Signs and Symptoms

Newborn
Infant or toddler
1. Failure to Thrive
2. Fever
3. Weight Loss
4. Nausea or Vomiting
5. Irritability
6. Jaundice
7. Strong smelling urine
8. Hematuria
9. Abdominal Pain or Flank Pain
Child
1. Same as for adult Urinary Tract Infection
2. Dysuria
3. Urinary Frequency or urgency
4. Urine hesitancy
5. Lower Abdominal Pain
6. New onset Urinary Incontinence
7. Urine Odor does not predict Urinary Tract Infection

Diagnosis

General
1. Urinalysis dipstick can be used to rule-out UTI
  1. High Negative Predictive Value if normal
    1. Exception: Not sensitive in dilute urine (SG<1.005)
      1. Shaw (1998) Pediatrics 101:E1 [PubMed]
    2. However, Urinalysis may still have a 6-10% False Negative Rate
  2. Initial criteria for empirically starting UTI treatment
    1. Catheterized specimen AND
    2. Positive for Leukocyte esterase, nitrite or microscopy with Urine WBCs or Bacteria
2. Urine Culture is required for UTI diagnosis
  1. Urinalysis dipstick testing is not diagnostic (use only for empiric initial therapy)
  2. Urine Culture is mandatory when a Urinary Tract Infection is suspected
    1. Urine sample for culture must be via catheter or SPA in children under 24 months
    2. Diagnosis requires pyuria and a catheterized specimen with >50,000 colonies of a single organism
Urine Sample Techniques
1. Urine catheter specimen
  1. Recommended if child under age 2 years
  2. Consider Bladder Ultrasound first (one third of infants have a dry catheterization)
    1. Visualize Bladder in transverse plane
    2. Bladder width >2 cm holds sufficient urine for catheterization sample
2. Suprapubic Aspirate (SPA, rarely done in U.S. practice)
  1. Consider for child under age 6 months old
3. Clean catch Urine (especially first morning void)
  1. See Noninvasive Urine Collection (includes Quick-Wee Method, Bladder stimulation technique)
  2. Possible in young children, but requires patience
4. Urine Bag Collection (Not recommended)
  1. High Incidence of contamination
  2. May only be used to rule out UTI when risk of UTI is low (<1%, see above)
  3. If abnormal, catheterized sample or suprapubic aspirate is required
  4. Avoid Urine Culture of a bag specimen (False Positive culture rate >88%)
Urinalysis Individual Factors (Sensitivity, Specificity)
1. Urine Leukocyte Esterase (small or greater)
  1. Test Sensitivity: 83%
  2. Test Specificity: 78%
  3. Probability of UTI when positive: 30%
2. Urine Nitrite
  1. Requires 4 hours within the Bladder to form (young children do not hold their urine)
  2. Test Sensitivity: 53%
  3. Test Specificity: 98%
  4. Probability of UTI when positive: 75%
3. Urine White Blood Cells (10 or greater; some criteria use 5 or greater) on microscopy (hpf)
  1. Test Sensitivity: 73%
  2. Test Specificity: 81%
  3. Probability of UTI when positive: 30%
4. Urine Bacteria present on microscopy
  1. Test Sensitivity: 81%
  2. Test Specificity: 83%
  3. Probability of UTI when positive: 35%
5. Urine Red Blood Cells on microscopy
  1. Test Sensitivity: 47%
  2. Test Specificity: 78%
  3. Probability of UTI when positive: 19%
Urinalysis Combined Factors (Sensitivity, Specificity)
1. Urine Leukocyte Esterase AND Urine Nitrite Combined
  1. Test Sensitivity: 93%
  2. Test Specificity: 72%
2. Urine Leukocyte Esterase AND Urine Nitrite AND positive microscopy (Bacteria or WBC>5/hpf)
  1. Test Sensitivity: 99.8%
  2. Test Specificity: 70%
  3. Very high Negative Predictive Value
Urine Culture
1. See Urine Culture for diagnostic criteria
2. Positive if catheterized specimen with >50,000 colonies of a single organism
3. Culture sample within 4 hours or refrigerate
4. Obtain in all children <10 years old when Urinalysis is evaluated (Urinalysis can be unreliable)
Resources
1. UtiCalc Tool (University of Pittsburgh)
  1. https:..uticalc.pitt.edu
  2. Predicts likelihood of UTI (tool recommends Urinalysis if >2% risk)

Labs

Precautions
1. Always obtain urine sample before Antibiotics are started (Antibiotics rapidly render sterile urine)
Standard
1. Urinalysis
2. Urine Culture
Suspected Pyelonephritis
1. Complete Blood Count (CBC)
2. Blood Culture
  1. Indicated for febrile hospitalized child
  2. UTI with bacteremia may necesitate earlier imaging
3. Inflammation Markers (70-80 sensitive, not specific)
  1. Erythrocyte Sedimentation Rate
  2. C-Reactive Protein
4. Renal Function tests)
  1. Blood Urea Nitrogen
  2. Creatinine

Imaging

General
1. First UTI in age <5 years old no longer requires imaging (unless indicated as below)
2. Imaging goals are to identify children with modifyable risk factors for Recurrent UTI (and renal scarring risk)
  1. Vesicoureteral Reflux
  2. Posterior uretheral valves (males)
3. Does not appear to change management or outcome (significant VUR Incidence is low)
4. Zamir (2004) Arch Dis Child 89:466-8 [PubMed]
Imaging indications
1. Renal and Bladder Ultrasound (RBUS)
  1. Indications
    1. First UTI with fever at least 101.3 F (38.5 C) age under 2 years
    2. Recurrent UTI ages 2 to 5 years
  2. Timing
    1. Within 48 hours for severe infection or prolonged course
    2. Otherwise wait until acute infection resolves, and obtain within 6 months of acute infection
2. VCUG
  1. Do not routinely obtain for first febrile UTI
  2. Do not obtain until infection has resolved (wait at least 3-6 weeks after infection)
  3. Indicated for abnormal Ultrasound showing renal scar, Hydronephrosis or other signs of high grade VUR
  4. May also be indicated for second febrile Urinary Tract Infection (discuss with pediatric urology)
3. DMSA Renal Cortical Scan
  1. Less commonly used now (defer to local pediatric urology consultants)
  2. May be preferred in girls as spares some ovarian radiation seen in VCUG

Evaluation
Decision Protocols to treat empirically while awaiting Urine Culture

University of Pittsburgh UTI Calculator
1. https://uticalc.pitt.edu/

Management
Overall protocol for a febrile child between ages 2 months and 24 months

Step 1: Child requires immediate empiric antimicrobial therapy
1. Go to Step 4
Step 2: Likelihood of Urinary Tract Infection is <1% (see Decision to evaluate for UTI as above)
1. No urine testing required
2. Complete additional evaluation of a febrile child
3. Follow-up in 1-2 days for re-evaluation
Step 3: Negative Urinalysis (LE, Nitrite, micro) by any method
1. No further urine testing required
2. Complete additional evaluation of a febrile child
3. Follow-up in 1-2 days for re-evaluation
Step 4: Urine Culture by catheter, clean catch or suprapubic aspirate only
1. Determine disposition based on inpatient criteria below
2. Start Antibiotics as described below
Step 5: Negative Urine Culture
1. Stop Antibiotics
2. Complete additional evaluation of a febrile child
3. Follow-up for Recurrent Fever
Step 6: Positive Urine Culture
1. Treat for 7-14 days adjusted for Urine Culture sensitivities
Step 7: Renal and Bladder Ultrasound
1. Obtain at any time after Urinary Tract Infection is confirmed
2. Positive Ultrasound for anatomic abnormalities (e.g. Hydronephrosis)
  1. Obtain VCUG to evaluate for Grade IV to IV vesicoureteral reflux
References
1. Roberts (2011) Pediatrics 128(3): 595-610 [PubMed]

Management
Inpatient criteria

Ill appearing or toxic children
Children unable to maintain oral hydration
Risk of renal scar
Febrile children under age 6 months to 1 year old

Management
Antibiotics

Precautions
1. Initiate early empiric Antibiotics after urine sample when UTI is suspected in young children
  1. Delaying treatment for Urine Culture results (48 hours) increases renal scarring risk
2. Oral Antibiotics are as effective as intravenous Antibiotics for UTI in Children >2 months of age
  1. When IV Antibiotics are used, short course (2-4 days) followed by oral Antibiotics is effective
  2. Strohmeier (2014) Cochrane Database Syst Rev (7):CD003772 [PubMed]
  3. Desai (2019) Pediatrics 144(3):e20183844 [PubMed]
Oral Antibiotics
1. Duration
  1. Typical course: 7 to 14 days
  2. Febrile UTI is treated for 10 days or more
    1. Five day course may be sufficient in otherwise uncomplicated febrile UTI age 3 months to 5 years
      1. Montini (2024) Pediatrics 153(1):e2023062598 +PMID: 38146260 [PubMed]
2. Amoxicillin-clavulonate (Augmentin) 45 mg/kg/day divided twice daily
  1. E coli resistance to Amoxicillin is increasing (>50% in some regions as of 2016)
3. Trimethoprim Sulfamethoxazole (Septra, Bactrim)
  1. Dosing: 6-12 mg/kg/day TMP,30-60 mg/kg/day SMZ divided bid
  2. Avoid under age 2 months
  3. Poor renal penetration
  4. E coli resistance to TMP-SMZ is also increasing (25% in some regions as of 2016)
4. Second generation or Third Generation Cephalosporins
  1. Cefixime (Suprax)
    1. Expensive
    2. Day one: 16 mg/kg for the first day
    3. Next: 8 mg/kg/day in single dose or divided every 12 hours
  2. Cefpodoxime (Vantin) 10 mg/kg/day divided every 12 hours
  3. Cefprozil (Cefzil) 30 mg/kg/day divided every 12 hours
  4. Cephalexin (Keflex) 25-50 mg/kg/day orally divided three to four times daily
    1. Good renal parenchymal penetration and Pyelonephritis coverage
Intravenous Antibiotics for hospitalized children
1. Preferred agents
  1. Cefotaxime 50 mg/kg IV every 8 hours
  2. Ceftriaxone (Rocephin) 75-100 mg/kg every 24 hours
  3. Ceftazidime 50 mg/kg every 8 hours
2. Other Antibiotic options
  1. Gentamicin
    1. Neonates <8 days: 4 mg/kg/day divided every 8 hours OR once daily
    2. Neonates 8 to 60 days: 5 mg/kg/day divided every 8 hours OR once daily
    3. Children >60 days: 7.5 mg/kg/day divided every 8 hours OR once daily
  2. Tobramycin 5 mg/kg/day divided every 8 hours
  3. Piperacillin 300 mg/kg/day divided every 6-8 hours

Management
UTI Prophylaxis

Indications
1. Prophylaxis is no longer routinely recommended prior to completion of evaluation
2. Discuss with local pediatric urology consultants
Medications (at bedtime if toilet trained)
1. Nitrofurantoin (Furadantin, Macrodantin, Macrobid)
  1. Dosing: 1-2 mg/kg once daily
  2. Preferred UTI prophylaxis agent
    1. Associated with less Antibiotic Resistance than other prophylaxis agents
  3. Adverse effects
    1. May be associated with greater gastrointestinal side effects (Nausea, Vomiting, Abdominal Pain)
2. Trimethoprim Sulfamethoxazole (Septra, Bactrim)
  1. Avoid under 2 months
  2. Dosing
    1. Nightly: 2 mg TMP/10 mg SMZ per kg at bedtime
    2. Bi-weekly: 5 mg TMP/25 mg SMZ per kg twice weekly
3. Nalidixic Acid (NegGram)
  1. Dosing: 30 mg/kg/day divided bid
4. Methenamine mandelate 75 mg/kg/day divided bid
5. Sulfisoxazole (Gantrisin) 10-20 mg/kg/day divided bid
Other prevention
1. Circumcision in uncircumsized boys
2. Treat comorbid Constipation

Management
Evaluation for secondary urologic anomaly

Indications
1. See Imaging above
2. Family History may dictate screening despite no prior personal UTI history
  1. Preschool siblings of child with urologic anomaly
  2. Preschool child of parent with vesicoureteral reflux
Protocol
1. See Imaging above

Complications

Acute
1. Sepsis
2. Renal Abscess
3. Acute Kidney Injury
Chronic
1. Renal scarring
  1. Retrospective population study of UTI in first 5 years of life shows low risk for renal scarring (1.25%)
  2. Hughes (2024) Br J Gen Pract 74(743): e371-8 [PubMed]
2. Recurrent Urinary Tract Infection
3. Chronic Kidney Disease (including End Stage Renal Disease)
4. Hypertension
5. Preeclampsia

Prognosis
Vesicoureteral Reflux

Risk End-stage renal disease if renal scarring occurs
1. Responsible for 20% of end-stage renal disease
Spontaneous Resolution Rates for Ureteral Reflux
1. Grade I: 70-80%
2. Grade II: 70-80%
3. Grade III: 50%
4. Grade IV: 15%
5. Grade V: <15%

Prevention
Prevent renal scars in high risk children

Children under age 2 years
Recurrent Pyelonephritis
Pyelonephritis with urinary anatomic abnormality
Pyelonephritis untreated for more than 3 days

References

(2019) Sanford Guide, accessed on IOS 9/24/2019
Orman and Horeczko in Herbert (2018) EM:Rap 18(3): 17-8
(2016) Presc Lett 23(6): 33-4
(2011) Pediatrics 128(3):595-610 [PubMed]
Alper (2005) Am Fam Physician 72:2483-8 [PubMed]
Bulloch (2000) Pediatrics 106:e60 [PubMed]
Fisher (1999) Pediatrics 104:109-11 [PubMed]
Hoberman (1999) Pediatr Infect Dis J 18:1020-1 [PubMed]
Hoberman (1999) Pediatrics 104:79-86 [PubMed]
Honkinen (2000) Pediatr Infect Dis 19:630-4 [PubMed]
Roberts (2012) Am Fam Physician 86(10): 940-6 [PubMed]
Roberts (2000) Am Fam Physician 62(8): 1815-22 [PubMed]
Ross (1999) Am Fam Physician 59(6): 1472-8 [PubMed]
Veauthier (2020) Am Fam Physician 102(5): 278-85 [PubMed]