Transcript Urinary Tract Infections

Urinary Tract
Infections
Objectives
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Know the predominant organisms causing
urinary tract infection in children
Be able to evaluate a pre-school age child with a
urinary tract infection
Differentiate between upper and lower urinary
tract infections in patients of differing ages
Know the appropriate antibiotic treatment for
acute cystitis and the role of imaging
CONTINUITY CLINIC
Background
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Overall prevalence of UTI in febrile infants 5%
Recurrent UTIs may lead to:
Renal scarring
 HTN
 Renal dysfunction and failure
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Presence of another source of fever (URI,
AOM) does NOT rule out UTI
Parents reporting “foul-smelling” urine does
NOT correlate with UTI
CONTINUITY CLINIC
Host Factors Associated with UTI
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Caucasian
Females
Uncircumcised
Males
Breastfed
Familial History
Anatomic
CONTINUITY CLINIC
2-4x prevalence
2-4x prevalence vs.
circumcised males
4x higher than circumcised
males until 1 year of age
Lower rates due to IgA Infants
Genetic Predisposition
GU Reflux most common at
1% prevalence; 40-50% of
young children with febrile UTI
Based on data from Hoberman, A, et al. Prevalence or urinary tract infection in
febrile infants. J Pediatr 1993; and Shaw, KN et al. Prevalence of urinary tract
infection in febrile young children in the emergency department. Pediatrics 1998.
Demographic Group
Prevalence
Odds
Circumcised Males > 1
year old
<1%
0.01 (1/100)
Circumcised Males < 1
year old
2%
0.02 (1/50)
African American
Females
4%
0.04 (1 in 25)
Uncircumcised Males < 2
year old
8%
0.09 (1/12)
White Females < 2
years old
16%
0.19 (1/5)
CONTINUITY CLINIC
Host Factors Associated with UTI
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Sexual Activity
Not well documented; use
of spermicidal condoms
and jelly associated with E.
coli bacteruria
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Physiologic
Abnormality
Dysfunctional voiding –
40% of toilet trained
children with first UTI and
80% with recurrent UTI
CONTINUITY CLINIC
Symptoms of Dysfunctional Voiding
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Withholding behaviors – squatting, leg crossing
Bladder/bowel incontinence – diurnal enuresis
Abnormal elimination pattern – small frequent
voids with incomplete emptying
Failure to relax urinary sphincter and pelvic
musculature results in overactive detrusor
contractions causing bladder-sphincter dyssynergy
 It is estimated that 15% of pediatric population have
dysfunctional voiding – consider diabetes neurogenic
bladder
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CONTINUITY CLINIC
Differential
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Vulvovaginitis
Viral cystitis (eg adenovirus)
Enterbiasis (pinworms)
Urinary calculi
STD
Vaginal foreign body
Epididymitis
CONTINUITY CLINIC
Evaluation
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UTI diagnosis SHOULD NOT be established
by a culture of urine collected in a bag
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Correct diagnosis requires culture of clean catch,
catheterized, or suprapubic tap specimen
Urine dipstick can rule out UTI, but positive
result is insufficient to diagnose UTI due to
potential for false positives
CBC/CRP are unnecessary
CONTINUITY CLINIC
Understanding the UA
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Nitrite
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produced by conversion of nitrate by the enzyme nitrate
reductase contained by some bacteria, such as E. coli,
Klebsiella and Proteus
False positives occur when bacterial overgrowth occurs in the
setting of delay prior to lab testing
Urine must remain in the bladder 4 hours to accumulate
detectable amount of nitrite, therefore an uncommon finding
in young children
Positive nitrite very likely to indicate UTI
Staph saprophyticus does not produce nitrite.
CONTINUITY CLINIC
Understanding the UA
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Leukocyte esterase (LE)
enzymatic marker for WBCs
 suggestive of UTI, however, does not always signal a
true UTI.
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CONTINUITY CLINIC
Sensitivity and Specificity of
Components of Urinalysis
TEST
SENSITIVITY %
SPECIFICITY %
Leukocyte esterase
83
78
Nitrite
53
98
LE & Nitrite +
Microscopy: WBCs
93
73
72
81
Microscopy: bacteria
81
83
LE/Nitrite/micro +
99.8
70
CONTINUITY CLINIC
Definition of UTI
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Clean catch
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> 100,000 organisms of one bacteria
Catheterized
>50,000 cfu/ml in children < 2 yr
 If 10,000-50,000 repeat urine cx suggested
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>10,000 on repeat  UTI
Suprapubic (gold standard)
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Any growth
CONTINUITY CLINIC
Radiologic Imaging
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Ultrasound of Kidneys
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Assess for structural anomalies
Urgent ultrasound may be necessary if there is inappropriate
response to treatment within 24-48 hours - rule out
obstruction or abscess
VCUG
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Rule out vesico-ureteral reflux (VUR)
It has been shown that there is no difference in VUR if
VCUG is performed early or late, and is generally acceptable
once patient is afebrile.
Patients are placed on antibiotic prophylaxis until completion
of imaging studies
CONTINUITY CLINIC
When to Consider Imaging
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Children < 5yr with febrile UTI
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Girls under 3 yr with first UTI
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Males of any age with a first UTI
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Kids with recurrent or resistant UTI
CONTINUITY CLINIC
When to Hospitalize
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Literature states that infants > 2mo can be
managed as outpatients on oral meds with close
follow-up unless toxic and unable to tolerate
oral hydration and meds, in which case
hospitalization is necessary
CONTINUITY CLINIC
Microbiology
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E. coli accounts for about 80% of UTIs in
children.
Other bacteria include: Gram negative species
(Klebsiella, Proteus, Enterobacter, and
Citrobacter) and Gram positive species (Staph
saprophyticus, Enterococcus, and rarely, S.
aureus).
CONTINUITY CLINIC
Treatment
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Generally treated with: TMP/SFX or
cephalosporins for:
7-14 days in children 2mo – 2 years old with cystitis
 10-14 days for pyelonephritis
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Choice of antibiotic ultimately guided by
sensitivity of bacterial isolate
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neonates usually hospitalized and treated with IV
antibiotics, followed by oral. Generally, patients are
switched to oral antibiotics following 2-4 days of IV
antibiotics
CONTINUITY CLINIC
Treatment in Outpatient Setting
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TMP/SMX – contraindicated in infants <
2months
Cephalosporins (cefixime) - no enterococcus or
pseudomonas coverage
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Ceftriaxone if patient noncompliant or emesis is
concern
Nitrofuantoin, Amoxicillin – not adequate for
pyelonephritis
CONTINUITY CLINIC
Prophylaxis
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TMP/SMX
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Nitrofurantoin
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Amoxicillin
CONTINUITY CLINIC
CONTINUITY CLINIC