Urinary Tract Infection
September 2014
Pediatric Continuity Clinic Curriculum
Created by: Michelle Y. Spencer, MD
Objectives
• Describe the association of urinary tract
infections (UTIs) and unexplained fever in
infants
• Discuss the management of suspected UTI
• Review the use of radiologic studies to diagnose
vesicoureteral reflux (VUR)
Case #1
A 3 m.o. male presents to acute clinic with 2 day
history of tactile fever, frequent emesis and poor
feeding. On exam, baby is fussy with temperature
38.4, HR 115 and BP 94/59 and no other significant
abnormalities.
Discussion Questions:
• What is the next step in evaluating this patient
with fever?
• What are the indications for hospitalization?
What is the next step in evaluating this
patient with fever?
• Obtain urinalysis
– The prevalence of UTI in febrile infants who have no
obvious source is about 7-9% in those < 3 m.o.
regardless of sex
– It decreases to 2% for males > 3 m.o. and females >
12 m.o.
• The “gold standard” for diagnosing UTI is the
urine culture obtained by suprapubic
aspiration, urethral catheterization, a ‘clean
catch’ midstream specimen and bag collection
(least preferable).
Interpreting the urine dipstick
• Nitrite test: presence of gram-negative bacteria
in urine that reduce dietary nitrate to nitrite
– 37% sensitive and 100% specific. Positive predictive
value 90% and negative predictive value 100%
• Leukocyte esterase test: presence of leukocytes
(best performed on a fresh specimen)
– 73% sensitive and specific. Positive predictive value
34% and negative predictive value 95%
– Presence may be related to vaginal secretions,
dehydration, interstitial nephritis, etc.
General Criteria to Diagnose UTI
• Suprapubic Aspiration
– Any growth of gram negative bacilli or > 1,000
units/ml of gram positive cocci
• Urethral Catheterization
– Greater than 50,000 colony forming units/ml for
circumcised/uncircumcised males and all females
• Midstream Clean Catch
– Greater than 100,000 colony forming units/ml.
These values pertain to pure, one pathogen colony
growth
What are the indications for hospitalization?
• Infants < 3 months old should be hospitalized to
receive IV fluids and antibiotics.
– NOTE: Each hospital might have different protocol
• Indications for hospitalization for older infants
through adolescents:
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–
–
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Dehydration
Inability to take oral fluids
Ill appearing infant or child
Patients who have chronic diseases: sickle cell, diabetes,
cystic fibrosis or urinary tract abnormalities
– Presence of perinephric abscess
Flow Chart for Evaluation & Management of
UTI in Older Children and Adolescents
Case #2
A 5 y.o. female presents with 3 day history of
fever and dysuria. Clean catch urine dipstick
reveals spec grav 1.015, pH 6.0, positive nitrites,
bacteria and leukocyte esterase.
Discussion Questions:
• What is the most likely organism causing this
patient’s symptoms?
• What is the most appropriate next step in
management?
What is the most likely organism
causing this patient’s symptoms?
• Escherichia coli (E. coli) accounts for up to 70% of
urinary tract infections
• Other bacterial pathogens:
–
–
–
–
–
Pseudomonas aeruginosa (nonenteric gram negative)
Enterococcus faecalis
Klebsiella pneumoniae
Group B strep (predominately in neonates)
Proteus mirabilis (boys > 1 y.o. and associated with
renal calculi)
– Coag negative Staphylococcus
Other pathogens causing UTI
• Fungal UTI caused by Candida albicans
– Associated with instrumentation or the urinary
tract
• Viral UTI caused by Adenovirus and BK virus
(hemorrhagic cystitis)
What is the most appropriate next
step in management?
1. Send urine culture
2. Start antibiotic therapy
o Timely appropriate treatment is helpful in preventing
renal injury that may lead to scarring
Cystitis
– Most cases 3-7 day course of antibiotics
Pyelonephritis
– Start 10 day course of appropriate oral or IV antibiotic for
initial treatment
– In cases of prolonged fever or renal abscess consider 14
days
3. Obtain radiologic imaging
Appropriate Antibiotic Therapy
• Uncomplicated Cystitis: Choice of agents
-Cefixime(Suprax)
-Cefdinir(Omnicef)
-Ceftibuten (Cedax)
- Ciprofloxacin
- Nitrofuratoin
• There is increasing resistance to Amoxicillin, Ampicillin,
Trimethoprim-sulfamethoxazole (> 2 months of age),
Amoxicillin-clavulanate, Cephalexin
• Uncomplicated Acute Pyelonephritis
– Similar to cystitis Ciprofloxacin 500 mg BID or extended release
1000 mg once daily
Adjust antibiotic as indicated after bacterial sensitivity available.
Radiologic Imaging
• Fluoroscopic VCUG is the gold standard for
diagnosing VUR
– VCUG should be done after infected urine becomes
sterile or after completion of full course of antibiotics,
though studies have shown that it could be done after
48-72 hours after initiation of antibiotics
• Renal ultrasound is safe and fast way of detecting
congenital renal urinary tract anomalies that may
be associated with UTI and VUR
– Can be obtained within 2-4 weeks of initial UTI
Indications for Ultrasonography
• Patients < 2 years of age with a first febrile
UTI
• Patients of any age with recurrent febrile
UTIs
• Patients of any age with a UTI who have a
family history of renal or urologic disease,
poor growth,or hypertension
• Patients who do not respond as expected to
appropriate antimicrobial therapy
Indications for Voiding Cystourethrogram
• Patients of any age with two or more febrile
UTIs.
• Patients of any age with a first febrile UTI who
have any anomalies on renal ultrasound or a
family history of renal or urologic disease; and
children with poor growth or hypertension
The content on the next slide has small
font, but is packed with important
information for review at your leisure
Case #3
A 2 y.o. boy presents to clinic for follow up after
completing 14 day course of antibiotics for
pyelonephritis. You ordered a VCUG and the results
reveal bilateral vesicoureteral reflux (grade III on
the right and grade IV of the left).
Discussion Questions:
• What is the most appropriate next step in
management?
• Which condition has strong association with UTI ?
What is the most appropriate next
step in management?
• Start prophylactic antibiotic therapy
– Prophylactic dose if ¼ to ½ of the therapeutic dose
Suggested Dosing
TMP-SMZ 2 mg/kg daily or
5 mg/kg twice weekly
Nitrofurantoin 1-2 mg/kg daily
Cephalexin 10 mg/kg daily
Ampicillin 20 mg/kg daily
Amoxicillin 10 mg/kg daily
Vesicoureteral reflux (VUR)
• Occurs when urine within the bladder flows back up
into the ureter and often back into the kidney.
– Primary concern is exposing the kidneys to infected urine
→ acute pyelonephritis and renal scarring
• All grades of VUR have potential for spontaneous
resolution over a period of time. Percent resolution at
5 year follow up
–
–
–
–
–
Grade I 82%
Grade II 80%
Grade III 46%
Grades V 30%
Grade V 13%
Which condition has strong
association with UTI ?
• CONSTIPATION
– The association is believed to result from
compression of the bladder and bladder neck
– Also distended colon or fecal soiling provides an
abundant reservoir of pathogens
• Constipation in children increases the
likelihood of urinary incontinence bladder
overactivity, dysfunctional voiding, recurrent
UTIs and persistence or progression of VUR
Other host risk factors predisposing to
Urinary Tract Infection
•
•
•
•
•
•
•
•
•
•
•
Lack of circumcision of male infants (<1 year of age)
Male gender in first 6 to 8 postnatal months
Lack of breastfeeding in first 6 postnatal months
Constipation
Dysfunctional voiding pattern
Recent history of antibiotic use for any purpose
Urinary tract infection in the past 6 months
Indwelling catheters or intermittent catheterization
Family history of recurrent urinary tract infection
Recent sexual intercourse
Use of a diaphragm for birth control or spermicidal agents
Management of VUR
• Medical management is appropriate for all
stages of VUR particularly in younger children
– Prophylactic antibiotics, treatment of constipation
and voiding dysfunction if present
• Surgical management is reserved for patients
who fail medical management or Grade IV/V
– Breakthrough UTIs or persistent VUR with evidence
of renal injury
• Close monitoring with periodic VCUG
examination (yearly – to every 2 years)
PREP QUESTIONS
A 4-year-old girl presents to your office for
evaluation 1 month after an episode of
pyelonephritis, after which she was diagnosed with
grade III vesicoureteral reflux. The patient is healthy
with normal growth parameters and development.
She has no significant past medical history or past
surgical history. According to her parents, she has
been toilet trained since 18 months of age. Findings
on physical examination are unremarkable; vital
signs are normal. Her urine analysis in the office
shows specific gravity of 1.010, pH of 6.0, and no
protein, blood, leukocyte esterase, or nitrites. There
is no history of urinary tract infections in the parents
or the 2-year-old sister.
PREP 2014 #214
Of the following, the MOST appropriate next
step in the management of this patient is to
A. evaluate the patient for voiding dysfunction
B. order urine culture for evaluating resolution of
the urinary tract infection
C. order serum electrolytes and serum creatinine
for evaluating renal function
D. refer the patient for surgical correction of her
reflux
E. screen the 2-year-old sibling with voiding
cystourethrography
PREP 2014 #214
A 3-month-old female infant presents to your office for
follow-up of pyelonephritis diagnosed 2 months ago. After
treatment of her urinary tract infection, she had a contrast
voiding cystourethrogram (VCUG) that showed narrowing
of the distal urethra and a normal urinary stream upon
voiding (Item Q36). Her physical examination is
unremarkable. She is currently on oral amoxicillin for
urinary tract infection prophylaxis.
Of the following, the MOST appropriate next step in the
management of this patient is
A. intravenous pyelography
B. referral to urology for surgical correction
C. repeat urine culture
D. repeat VCUG in 1 year
E. stop prophylactic antibiotics
PREP 2014 #36
Narrow urethra on VCUG
(also termed spinning top urethral deformity)
References
– Pediatrics in Review Article: “Urinary tract
infections and Vesicoureteral Reflux in
Infants and Children” (2010)
– AAP Clinical Guideline or Practice Parameter
– Nelson’s reference
– Harriet Lane
– Uptodate
BONUS PREP QUESTIONS
If time permits 
A 17-year-old, sexually active boy has complaints of
intermittent burning with urination for the last 2
weeks. He says he sometimes sees some staining
on his underwear but has not noticed any penile
discharge or genital lesions. He reports that he has
never had a sexually-transmitted infection and that
he always uses condoms. He is otherwise healthy
and has no systemic complaints, hematuria, or
urgency.
On physical examination, he is at sexual maturity
rating 5 for pubertal development. Other than
some moistness at the urethral meatus, his genital
examination findings are normal.
PREP 2014 #20
Of the following, the organism MOST likely
responsible for this boy’s symptoms is
A.
B.
C.
D.
E.
Chlamydia trachomatis
Escherichia coli
Mycoplasma genitalium
Neisseria gonorrhoeae
Ureaplasma urealyticum
PREP 2014 #20
A 1-year-old with genitourinary malformations
recently underwent corrective urological surgery
and was discharged home in stable condition
with an indwelling urinary catheter. The patient
presents 10 days after discharge with fever and
vomiting. Physical examination is significant only
for a febrile infant (40.1°C) with mild
dehydration. The urine is cloudy, and a spot
urine test strip analysis shows a pH of 6.0,
specific gravity of 1.040, 4+ leukocyte esterase,
and no nitrites, blood, or protein. The patient is
admitted to the hospital parenteral antibiotics
are started.
PREP 2014 #72
Of the following, the MOST appropriate
empiric antibiotic choice for this patient is
intravenous
A.
B.
C.
D.
E.
ampicillin
ampicillin and ceftriaxone
ceftriaxone
cefuroxime and gentamicin
gentamicin
PREP 2014 #72
THANK YOU!