Urinary Tract Infections in kids are a recurring clinical question that bugs us as clinicians… Why is Urinary Tract Infection in children different from cystitis or pyelonephritis in adults? How hard should we be looking for UTI, and what’s the best way to confirm or exclude the diagnosis?
In this podcast we discuss the diagnosis, important differentials, and treatment of pediatric Urinary Tract Infection.
UTI PEMcast outline
[cp] Hello, disclaimer, introduction
Common clinical problem, esp in FWS – urinalysis = most useful test
Significant consequences if missed
Controversies for discussion next episode (incl when to treat with IV Antibiotics, how long to treat, when to give prophylactic antimicrobials, proof-of-cure urine test, who to investigate, how to investigate, treatment of VUR)
[AH] Epidemiology (frequency in different age groups & genders, number of admissions) – approx 5% of FWS patients.
[SF] Aetiology (bacteria commonly involved) esp GI organisms – E coli, Klebsiella, Proteus, enterobacter, etc. Pseudomonas = more worrying.
Fastidious organisms eg mycobacteria
STIs (Chlamydia, gonorrhea)
[cp] Concepts / Definitions of:
Culture-proven vs presumed vs stricter definition (2 out of 3 cultures single-growth)
Cystitis vs pyelonephritis
Fever (may frequently be the only symptom)
Dysuria, Frequency, Urgency (in toddlers and older kids)
Neonates may have hypothermia; loose stools, vomiting, or just NQR
Background info (past medical history etc)
Recent antibiotic use
Shaikh et al JAMA 2007
General: well or sick, or Not Quite Right
Hydration, vital signs, fever (attention to measuring method)
Systems – alternative source of fever esp ENT, RS
Abdomen – tenderness (suprapubic / renal angle / RIF)
Perineum & genitalia (local inflammation)
Collection methods (SPA, in-out catheter, clean-catch, pads (special ones), bag (never))
Cleaning for collection (thorough)
Urine clarity / colour / smell not reliable to exclude/confirm infection!
[AH] Urinalysis: limited sensitivity in under 12 months (leukocyte esterase test, bladder dwell time) – need urgent urine microscopy
Specificity <100% but combination of nitrite & leuks highly suggestive
Do not treat without sampling urine first!
[AH] Urine microscopy: helpful
>100 WBCs/hpf diagnostic (<20 normal), 20-100 less clear
(infants may have UTI without mounting WBC response in urine or blood initially)
RBCs often increased
Bacteria on microscopy – significant esp if all same type (gram-negative rods); mixed = usually contaminant
Epithelial cells >20 suggests contaminated sample
[SF] Urine Culture: Pure growth of single organism is diagnostic if > 100, 000 (10^5) / mL
Mixed growth usually contaminant, but in young infants, check whether one strain predominates (eg mostly E coli with few others)
Negative culture after 48 hours excludes UTI for practical purposes
[SF] Urine sensitivities (if positive culture) – target antibiotics more specifically (some antibiotics not tested, eg enterococci in-vitro sensitivity to Trimethoprim not predictive of in-vivo situation)
[cp] Bloods: if young or unwell: Blood Culture, FBC, CRP, U&E, glucose (others depending on clinical scenario)
CSF sampling in neonate as part of septic screen, even if UTI confirmed (E coli UTI -10% have meningitis) (CXR too if indicated?)
Imaging: not in ED (follow-up imaging – see later)
[AH] Differential Diagnosis:
Local inflammation: Vaginosis, vaginitis, balanitis
Neighbourhood syndrome eg appendicitis
Systemic infection (few WBCs in urine)
*** commonest = Contaminant (esp in diarrhea, bag samples, inadequate cleansing – epithelial cells)
Supportive care (esp in younger & unwell patients)
Specific treatment: antibiotics – empiric based on local resistance/sensitivity patterns, then specific based on culture sensitivities
Some controversy, one approach is to admit all systemically unwell patients, and admit all suspected UTIs under 6 months age, for IV antibiotics (?any role for middle road of admitting for observation, treating with oral antibiotics)
[cp] Traditionally refer all males and all pre-pubertal females for follow-up with a General Pediatrician (they prefer culture-definite patients)
Some hospitals prefer U/S to be done prior to first clinic visit
[SF] Follow-up imaging controversial, may include U/S urinary tract, MCUG (in infants), DMSA scan, MAG-3 scan) All have different role / focus
Timing of U/S – swollen kidneys in first few weeks
[AH] Prophylactic antimicrobials also controversial – follow local policy
[all] Summary, Goodbye
Shaikh N, Morone NE, Lopez J, Chianese J, Sangvai S, D’Amico F, Hoberman A, Wald ER.
Does this child have a urinary tract infection?
JAMA. 2007 Dec 26;298(24):2895-904. Review.
PubMed PMID: 18159059.