Author:
Roger M.Barkin
Suzanne Z.Barkin
Description
- Bacteria colonize via retrograde contamination of rectal or perineal flora:
- UTI is defined by culture of a single organism of >50,000/mL on a catheterized or suprapubic specimen. Other collection techniques are not routinely used in young children for definitive diagnosis
- By 6 yr of age, 2% of boys and 8% of girls have had a UTI
- In infants 0-3 mo old, UTI is associated with a 30% incidence of sepsis
- Predisposing factors:
- Poor perineal hygiene
- Short urethra of female
- Female > male
- Infrequent voiding
- Constipation
- Sexual activity
- Male circumcision probably reduces risk
- Vesicoureteral reflux (VUR)/obstruction to flow
- Bladder dysfunction
- Hypercalciuria
Etiology
- UTI found in 4-7% of febrile infants
- Bacterial agents:
- Escherichia coli accounts for 80%
- Klebsiella pneumoniae
- Staphylococcus aureus
- Enterobacter species
- Proteus species
- Pseudomonas aeruginosa
- Enterococcus species
ALERT |
| UTIs in children may be difficult to diagnose without lab confirmation |
Signs and Symptoms
History
- Often nonspecific
- Neonates:
- Manifestations of sepsis
- Feeding difficulties
- Irritability, listlessness
- Fever, hypothermia
- 1 mo-3 yr of age:
- Fever
- Irritability
- Vomiting, diarrhea
- Abdominal pain
- Poor feeding, failure to thrive (slowing growth pattern)
- Hematuria
- In girls <2 yr, an increased risk is associated with those having ≥3 factors (<12 mo old, white, temperature ≥39°C, absence of other source of fever, fever ≥2 d)
- Children >3 yr of age:
- Dysuria
- Frequency
- Enuresis
- New onset of urinary incontinence
- Pain: Abdominal, suprapubic, back, costovertebral angle (CVA)
- Fever
- Hematuria
- Malodorous cloudy urine
- Systemic toxicity: High fever and chills with CVA tenderness
- Complications:
- Recurrent UTI
- Pyelonephritis
- Chronic renal failure:
- Scarring probably may be reduced by early detection and intervention although some evidence supports that the scarring represents a congenital finding
- Perinephric abscess
- Bacteremia/sepsis
- Urolithiasis
Physical Exam
- Vital signs, esp. temperature and blood pressure
- Toxicity
- Growth parameters
- Abdomen: Tenderness, esp CVA pain
- GU: Genitalia
Essential Workup
- UA with microscopic RBC and WBC counts and Gram stain for bacteria:
- UA alone has low diagnostic sensitivity in infants
- Causes of pyuria besides UTI include chemical (bubble bath) or physical (masturbation) irritation, dehydration, renal tuberculosis, trauma, acute glomerulonephritis, respiratory infections, appendicitis, pelvic infection, and gastroenteritis
- Dipstick reliability may be adversely impacted by dilute urine
- Leukocyte esterase correlates with presence of pyuria:
- Negative with symptomatic bacteriuria
- False positive with strep infections and vigorous exercise
- Positive nitrite test indicates presence of bacteria capable of fixing nitrate. False-negative tests common:
- Requires urine to be in bladder for 4 hr to convert
- Helpful if positive (few false positives)
- Gram stain of urinary sediment is more reliable than dipstick methods of diagnosis and superior to traditional UA
- UAs in neonates with documented UTIs may be normal. A positive UA (presence of leukocyte esterase, nitrite, or pyuria) in febrile infants <60 d of age is sensitive and specific in diagnosing UTIs with ≥ 50,000 CFU/mL
- Urine culture:
- Generally, >50,000 colony forming units (CFU)/mL of a single organism is used as the cut off for the presence of an infection. A lower colony count may be used for suprapubic aspiration
- Specimen should be cultured within 30 min or refrigerated
- False-negative results may be caused by dilution, improper culture medium, recent antimicrobial therapy, fastidious organisms, bacteriostatic agent in urine, and complete obstruction of ureter
- Clean-catch and bag specimens:
- Clean catch in cooperative male children
- Plastic bag collection adequate for UA (up to 70% contamination rate). Useful if negative:
- Clean the perineum (females) and glans (males) before application
- Can be used as a screening tool to rule out an infection if patient is not placed on antibiotics empirically and follow-up culture possible if the initial assessment is suggestive of infection
- Catheterization is the preferred technique to obtain urine because contamination is common with bag collection and clean catch:
- Bladder catheterization:
- Acceptable in all infants
- Higher success rate than suprapubic aspiration
- Aseptic technique essential
- Discarding the first 1-2 mL of urine before collecting specimen reduces contamination
- Suprapubic aspiration is used on rare occasions and does provide a good specimen:
- Full bladder optimal
- Most useful in infants
- Uncommonly used
- Ultrasound may be useful adjunctive measure to improve yield
Diagnostic Tests & Interpretation
Lab
- CBC and blood culture for young children with fever or nonspecific symptoms and no source on exam. Consider additional evaluation as appropriate
- Electrolytes, BUN, creatinine:
Imaging
- Children requiring radiologic evaluation:
- Infants <3 mo of age
- Males (increased association with anomaly) with first UTI
- Clinical signs and symptoms consistent with pyelonephritis
- Clinical evidence of renal disease
- Some suggest that girls <3 yr of age with a first UTI should be studied
- Females >3 yr of age
- First UTI in patients who have a family history of UTIs, abnormal voiding pattern, poor growth, HTN, urinary tract anomalies, or failure to respond promptly to therapy
- Second UTI
- Voiding cystourethrogram (VCUG):
- UTI is often associated with VUR and other genitourinary abnormalities and identified by VCUG. The importance of identifying VUR has been questioned
- Indicated if there is hydronephrosis or significant scarring
- Renal/bladder US:
- Ultrasonography is useful in excluding obstructive lesion and identifying children with solitary/ectopic kidney and some patients with moderate renal damage/scarring:
- Renal/bladder US is indicated to identify anatomic abnormalities. Should be done in children <2 yr with first febrile UTI, children with recurrent febrile UTIs, children with a UTI and family history of GU disease, poor growth, or hypertension as well as those children who do not respond as anticipated to antibiotics
- Nuclear cystogram (99Tc DMSA scan). Useful in documenting scarring and reflux nephropathy
- Further evaluation with nuclear medicine studies depends upon the grade of VUR and response to treatment
Differential Diagnosis
- Infection:
- Trauma:
- Chemical irritation/cystitis
- Perineal
- Sexual abuse
- Genitourinary
- Masturbation
- Foreign body
- Nephrolithiasis
- Diabetes
Initial Stabilization/Therapy
- Treat infants <3 mo old presumptively for sepsis if febrile and /or toxic until blood and other appropriate cultures are final
- Airway intervention for septic/acidotic infants with depressed respiratory drive
- Bolus of 20 mL/kg 0.9% NS for dehydration, hypovolemia, or sepsis; may repeat
ED Treatment/Procedures
- Initiate IV antibiotics in all febrile infants <3 mo with UTI:
- Outpatient oral antibiotic for 7-14 d for children discharged. Single day or one-dose regimen does not appear adequate. Should reflect local resistance patterns. Once sensitivity is known, antibiotic may need to be changed:
- Amoxicillin
- Amoxicillin/clavulanate
- Cephalexin
- Trimethoprim-sulfamethoxazole (TMP-SMX)
- Many suggest third-generation cephalosporin (cefixime, cefdinir) as first-line drug in treatment of children without GU anomaly because of changing resistance patterns. Oral therapy is generally adequate although close follow-up is essential to monitor clinical response and sensitivity of the etiologic organism
- Recent UTI treatment may provide information related to sensitivities in children with recurrent UTIs
- Length of treatment in children with afebrile UTI may be shortened to 5 d in children >2 yr. The short course is still not generally recommended in children with febrile UTI
- Parenteral antibiotics such as ceftriaxone may be required in the toxic child and those unable to tolerate oral therapy
- Patients should generally respond within 24-48 hr if pathogen is susceptible. If poor response, reassess patient
- If VUR is present, each UTI is generally treated. Benefit of low-dose prophylactic antibiotics or surgical correction is not proven
Medication
First Line
- Amoxicillin: 40 mg/kg/24 hr PO q8h
- Amoxicillin/clavulanate: 40 mg/kg/24 hr PO q8h
- Ampicillin: 100 mg/kg/24 hr IV q6h
- Cefdinir 14 mg/kg/24 hr PO per day
- Cefixime 16 mg/kg/24 hr PO on first day followed by 8 mg/kg/24 hr PO per day
- Ceftriaxone: 50-75 mg/kg/24 hr q12-24h IV/IM
- Cephalexin: 50 mg/kg/24 hr PO q6-12h
- Gentamicin: 2.5 mg/kg/dose IV q8h if full-term and age >7 d; 2.5 mg/kg/dose IV q12h if full term and age 0-7 d (special dosing regimens in infants <36 wk postconceptual age)
- TMP-SMX (Bactrim or Septra suspension): 5 mL liquid (of 40/200 per 5 mL) per 10 kg per dose PO b.i.d
Disposition
Admission Criteria
- Infants <3 mo
- Dehydration
- Ill appearance/toxicity/sepsis
- Suspected pyelonephritis
- Urinary obstruction
- Vomiting, unable to retain medications
- Failure to respond to outpatient therapy
- Immunocompromised patient
- Renal insufficiency
- Foreign body (indwelling catheter)
- Pregnant patient
Discharge Criteria
- Sufficiently hydrated
- Low risk for sepsis or meningitis
- Nontoxic
- Able to take oral antibiotics; compliant
Issues for Referral
- Patients needing admission often require a pediatrician, urologist, or infectious disease consultant, esp if there is VUR, renal anomaly, impaired renal function, recurrent infection, or hypertension
- Good follow-up is mand atory
Follow-up Recommendations
Monitoring of urine for sterility, monitoring for fever, further evaluation for underlying pathology, and following growth pattern
- American Academy of Pediatrics. Reaffirmation of AAP Guidelines—The diagnosis and management of the initial urinary tract infection in febrile infants and young children 2-24 months of age . Pediatrics. 2016:138:e2016.3026.
- ChaudhariPP, MonuteauxMC, ShahP, et al. The importance of urine concentration on the diagnostic performance of the urinalysis for pediatric urinary tract infection . Ann Emerg Med. 2017:70:63-71.
- CruzC, SpinaL. Are oral antibiotics as effective as a combination of intravenous and oral antibiotics for kidney infections . Ann Emerg Med. 2016:67:30-31.
- HobermanA, KerenR. Antimicrobial prophylaxis for urinary tract infection in children . N Engl J Med. 2009;361:1804-1806.
- MarksSD, GordonI, TullsK. Imaging in childhood urinary tract infection: Time to reduce investigations . Pediatr Nephrol. 2008;23:9-17.
- SahsiRS, CarpenterCR. Evidence-based emergency medicine/rational clinical examination abstract. Does this child have a urinary tract infection?Ann Emerg Med. 2009;53:680-684.
- ShaikhN, HobermanA, HumSW, et al. Development and validation of a calculator for estimating the probability of urinary tract infection in young febrile children . JAMA Pediatr. 2018;172:550-556.
- Subcommittee on Urinary Tract Infection, Steering Committee on Quality Improvement and Management; RobertsKB. Urinary tract infection: Clinical practice guidelines for the diagnosis and management of the initial UTI in febrile infants and children 2 to 24 months . Pediatrics. 2011;128:595-610.
- TzimenatosL, MahajanP, DayanPS, et al. Accuracy of the urinalysis for urinary tract infections in febrile infants 60 days and younger . Pediatrics. 2018; 141:18.
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