Pediatric Urinary
Tract Infections
Dr.Ammar Deeb
Department of Urology
2014
Introduction
• In infants and children, the urinary tract is a relatively
common site of infection.
• Urinary Tract Infections(UTIs) result in significant acute
morbidity , as well as long-term medical problems including :
delayed Hypertension and progressive renal dysfunction
Why do UTIs in children have that much
importance?
• Difficulty of diagnosis : unclear clinical features –
• Accurate diagnosis and timely treatment are vital in limiting
theses long-term sequelae, because the pediatric kidney is
susceptible to scarring and permanent renal damage
• UTI results in recognition of some important underlying
structural or neurogenic abnormality of the urinary tract
Incidence
• The incidence of UTIs in the pediatric population varies based on
gender and age
• Occurrences of first-time, symptomatic UTIs are highest in boys and
girls during the first year of life and markedly decrease after that
• overall prevalence of UTI in infants presenting with fever was 7.0%
• By age, the rates in girls were as follows:
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0-3 months - 7.5%
3-6 months - 5.7%
6-12 months - 8.3%
>12 months - 2.1%
• In febrile boys less than 3 months of age, 2.4% of circumcised
boys and 20.1% of uncircumcised boys had a UTI.
• During the first six months of life uncircumcised males have a
10 to 12-fold increased risk compared to circumcised males
for development of UTIs
• Only during the first year of life do males have a higher
incidence of UTIs when compared to females.
Pathogenesis of
urinary tract infection
Mechanism Of Infection
Ascending way
Hematogenous
Lymphatic
Direct
Extension
• uropathogens colonized the periurethral area ascend to the
bladder. can spread up the urinary tract to the kidneys and
possibly to the bloodstream (bacteremia).
• Urine is normally sterile.
• Entry of bacteria can result from turbulent flow during normal
voiding, voiding dysfunction, or catheterization
• sexual intercourse or genital manipulation may foster the
entry of bacteria into the urinary bladder
• Hematogenous spread is uncommon and usually occurs in
children who are immunocompromised ,during systemic
bacteremia (sepsis)
Organisms that may spread hematogenously to the urinary tract
include Staphylococcus aureus, Candida species, and tuberculosis
• Genitourinary tract fistulas, such as vesicovaginal can result in UTI
infections by direct extension
Aetiology
• Bacterial infections, with E coli being the most frequent pathogen,
causing 75-90% of UTIs. Other bacterial :
•
•
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Klebsiella species
Proteus species
Enterococcus species
Staphylococcus saprophyticus, especially among female
adolescents and sexually active females
• Streptococcus group B, especially among neonates
• Pseudomonas aeruginosa
• Fungi (Candida species) especially after instrumentation
• Adenovirus is a rare cause of hemorrhagic cystitis
Risk Factors
Alteration of flora
Anatomic
anomalybladder
dysfunction
Constipation
Circumcision
Risk factors
• Alteration of the periurethral flora by antibiotic therapy
• Children who receive antibiotics (eg, amoxicillin, cephalexin)
for other infections are at increased risk for UTI.
• These agents may alter gastrointestinal (GI) and periurethral
flora, disturbing the urinary tract's natural defense against
colonization by pathogenic bacteria
Anatomic anomaly------ VUR
• VUR is common in children with UTI.
• Epidemiologic surveys have shown that between 21% and
57% of children who have had bacteriuria are subsequently
found to have VUR.
• However, no correlation between reflux and UT predisposition
has been found.
• The importance of reflux lies in the fact that it allows bladder
bacteria renal access with subsequent potential for renal
damage.
• Bladder dysfunction
• Many Studies did not establish causality between UTI and
voiding dysfunction, UTI may initiate symptoms of bladder
dysfunction with variable persistence.
• In some situations, treatment of constipation or voiding
abnormalities, or both, has resulted in decreased frequency of
urinary infections.
• Circumcision and UTI
• For male infants, neonatal circumcision substantially
decreases the risk of UTI.
• during the first year of life, the rate of UTI was 2.15% in
uncircumcised boys, versus 0.22% in circumcised boys.
• Risk is particularly high during the first 3 months of life.
• in febrile boys younger than 3 months, UTI was present in
2.4% of circumcised boys and in 20.1% of uncircumcised boys
• Consider circumcision of male neonates.
• The AAP policy statement on circumcision is that
• “the health benefits of newborn male
circumcision outweigh the risks and that the
procedure's benefits justify access to this
procedure for families who choose it”
CLASSIFICATION
• Previously, UTIs were classified in numerous descriptive ways
such as complicated versus uncomplicated, or upper versus
lower tract.
• For practical purposes, pediatric UTIs may simply
be categorized into two types: first infections and recurrent
infections.
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•
•
•
The recurrent infections may then be categorized as
)1(unresolved bacteriuria during therapy,
(2) bacterial persistence at an anatomic site,
(3) re-infections.
DIAGNOSIS
• The febrile infant or child who has no other site of infection to
explain the fever, even in the absence of systemic symptoms,
should be assessed for the likelihood of pyelonephritis (upper
UTI).
• Most episodes of UTI during the first year of life are
pyelonephritis.
• Guidelines from the American Academy of Pediatrics
recommend considering the diagnosis of UTI in patients aged
2 months to 2 years with unexplained fever.
• identify any risk factors for the UTI.
(recent broad-spectrum antibiotic therapy, an anatomic
anomaly, voiding dysfunction, and constipation.)
SIGNS and SYMPTOMS:
• The history and clinical course of a UTI vary with the patient's
age and the specific diagnosis.
• No one specific sign or symptom can be used to identify UTI
in infants and children.
• Children aged 0-2 months
• usually do not have symptoms localized to the urinary tract.
UTI is discovered as part of an evaluation for neonatal sepsis.
• Neonates with UTI may display the following symptoms:
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Jaundice
Fever
Failure to thrive
Poor feeding
Vomiting
Irritability
• Infants and children aged 2 months to 2 years
Infants with UTI may display the following symptoms:
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Poor feeding
Fever
Vomiting
Strong-smelling urine
Abdominal pain
Irritability
• Children aged 2-6 years
• Preschoolers with UTI can display the following symptoms:
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Vomiting
Abdominal pain
Fever
Strong-smelling urine
Enuresis
Urinary symptoms (dysuria, urgency, frequency)
• Children older than 6 years and adolescents
School-aged children with UTI can display the following
symptoms:
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Fever
Vomiting, abdominal pain
Flank/back pain
Strong-smelling urine
Urinary symptoms (dysuria, urgency, frequency)
Enuresis
Incontinence ??!
• Physical examination findings in pediatric patients with UTI
can be summarized as follows:
• Costovertebral angle tenderness
• Abdominal tenderness to palpation
• Suprapubic tenderness to palpation
• Palpable bladder
• Dribbling, poor stream, or straining to void
URINE ANALYSIS
• The diagnosis of UTI is predicated on obtaining a good urinary
specimen, which can be difficult in children.
Routinely, there are four ways that urinary specimens are
obtained in children.
In order of least to most reliable for UTI diagnosis, they are
• )1(plastic bag attached to the perineum
• )2(midstream void,
• (3) catheter specimen, or
• (4) a suprapubic bladder aspirate
• (AAP) criteria for the diagnosis of UTI in children 2-24 months
are the presence of pyuria and/or bacteriuria on urinalysis and
of at least 50,000 (CFU) per mL of a uropathogen.
• In neonates younger than 2 months of age, criteria include the
presence of lower amounts of a single pathogen (10,00050,000 CFU/mL.)
• Significant pyuriais defined as >10 WBC/mm3.
• The concentration of motile bacteria can also be quantified,
with 107 bacteria per ml being deemed significant. This figure
corresponds to 8 organisms per highpowered field.
• The gold standard for the diagnosis of UTI is quantitative
urinary culture.
Haematology Studies:
• Hematologic studies do not tend to help in the diagnosis of
UTIs, although they should be obtained in patients who
appear ill.
• Obtain a complete blood count (CBC) and basic metabolic
panel for children with a presumptive diagnosis of
pyelonephritis.
• Perform blood cultures in febrile infants and older patients
who are clinically ill, toxic, or severely febrile.
• Renal function can be measured by serum creatinine and
blood urea nitrogen (BUN) levels; both may be elevated in
severe disease
• Electrolyte abnormalities may be present.
• Procalcitonin, a propeptide of calcitonin that has been found
to be elevated in response to bacterial endotoxins, has shown
promise in helping to diagnose pyelonephritis and early renal
damage.
Imaging Studies
• Imaging evaluation is important to the diagnosis and
management of UTI with the goal of altering or preventing
further morbidity
• It should be kept in mind that imaging studies are
recommended only if their findings may change clinical
management .
Necessary V/S Not cost-effective
it's important to adopt a selective approach which avoids
submitting normal children to unnecessarily invasive and costly
investigations while at the same time identifying those children
who have significant abnormalities such as reflux and renal
scarring.
The clinician's judgment should guide
the decision regarding imaging
studies, rather than a rigid rule
• Imaging studies are not indicated for infants and children with
a first episode of cystitis or for those with a first febrile UTI
who meet the following criteria:
 Assured follow-up
 Prompt response to treatment (afebrile within 72 h)
 A normal voiding pattern (no dribbling)
 No abdominal mass
Ultrasonography
Ultrasonography of the urinary tract is the imaging initial study
of choice in children with UTI
Urinary ultrasonography is safe, noninvasive study, and easy to
perform.
It is useful in excluding obstructive uropathy, as well as in
identifying a solitary or ectopic kidney and, in some cases,
moderate renal damage caused by pyelonephritis
Indications for renal and bladder ultrasonography:
 Febrile UTI in infants aged 2-24 months.
 Delayed or unsatisfactory response to treatment of a first
febrile UTI
 An abdominal mass or abnormal voiding (dribbling of urine)
 Recurrence of febrile UTI after a satisfactory response to
treatment
Finally, renal ultrasonography should be considered for any
child with a first febrile UTI in whom good follow-up cannot be
ensured.
(VCUG(Voiding cystourethrography
• may be indicated after a first febrile UTI if renal and bladder
ultrasonography reveal hydronephrosis, scarring, obstructive
uropathy, or masses or if complex medical conditions are
associated with the UT
• VCUG is recommended after a second episode of febrile UT
even if previous ultrasonographic examination findings were
unremarkable
• Children who respond to treatment for a UTI but afterwards
demonstrate an abnormal voiding pattern may need to
undergo standard VCUG
• The routine use of VCUG after the first UTI is not
recommended, since data do not support the use of
antimicrobial prophylaxis to prevent recurrent febrile UTI in
infants unless they have VUR above grade 4.
DMSA Scan
• DMSA imaging to detect renal scars is indicated in the clinically
high-risk group.
younger than 1 year of age who present with systemic
symptoms,
may have an unusual microorganism in their urine,
show resistance to antibiotic treatment,
have started treatment with antibiotics late.
TREATMENT
• Start antibiotics after performing urinalysis and obtaining a
urine specimen for culture in patients with UTI
• Empiric antibiotics should be chosen for coverage of the most
common uropathogens, namely Escherichia coli and
Enterococcus, Proteus, and Klebsiella species
• Patients with a nontoxic appearance may be treated with oral
fluids and antibiotics.
• Toxic-appearing patients must be aggressively treated with
intravenous (IV) fluids and parenteral antibiotics.
• IV until the patient is afebrile for 24 hours.
• Complete 10-14 days of therapy with an oral antibiotic
• Hospitalization is necessary for the following patients with
UTI:
 Patients who are toxemic or septic
 Patients with signs of urinary obstruction or significant
underlying disease
 Patients unable to tolerate adequate oral fluids or
medications
 Infants younger than 2 months with febrile UTI (presumed
pyelonephritis)
 All infants younger than 1 month with suspected UTI, even if
not febrile
• For parenteral therapy in a patient who is not allergic to
cephalosporins, initial treatment may consist of a single dose
of ceftriaxone (75 mg/kg IV/IM q12-24h).
• If the patient has cephalosporin allergy, initial treatment may
be with gentamicin (2.5 mg/kg IV/IM as a single dose).
• switched to an oral antibacterial agent at therapeutic doses
within the next 12-18 hours
Empiric therapeutic regimes for pediatric urinary tract
infections :
• Age < 2mo
• Cefotaxime 150 mg/kg/day IV/IM divided q6-8h plus ampicillin
100 mg/kg/day IV/IM divided q8h or
• Ceftriaxone 50-75 mg/kg/day IV/IM as a single dose or divided
q12h (ceftriaxone should not be used in infants younger than
6wk) or
• Ampicillin 100 mg/kg/day IV/IM divided q8h plus gentamicin
3.5-5 mg/kg/dose IV q24h if patient younger than 7d,
otherwise gentamicin 5-7.5 mg/kg/dose IV q24h
• Transition to oral antibiotic active against the offending
organism after 24-48h for total of 14d course
Age 2mo to 18y
Outpatient therapy:
Nitrofurantoin 5-7 mg/kg PO divided q6h for 3-10d or
Trimethoprim (TMP) and sulfamethoxazole 5-10 mg/kg/day PO
divided q12h, based on TMP component, for 3-10d or
Amoxicillin and clavulanic acid 20-40 mg/kg divided q8h for 310d or
Cephalexin 25-50 mg/kg/day PO divided q6h, not to exceed 3
g/day, for 10d
Inpatient therapy:
Ceftriaxone 50-75 mg/kg/day IV/IM as a single dose or divided
q12h plus ampicillin 100 mg/kg/day IV/IM divided q8h or
Cefotaxime 150 mg/kg/day IV/IM divided q6-8h plus ampicillin
100 mg/kg/day IV/IM divided q8h or
Ampicillin 100 mg/kg/day IV/IM divided q8h plus gentamicin 57.5 mg/kg/dose IV q24h
Transition to oral antibiotic active against the offending
organism after 24-48h
Cystitis
• Children with cystitis usually do not require special medical
care other than appropriate antibiotic therapy and
symptomatic treatment if voiding symptoms are marked.
• A 4-day course of an oral antibiotic agent is recommended for
the treatment of cystitis
Antimicrobial Prophylaxis
• Because renal scarring and damage have been shown to
occur only in the presence of infection, the goal of
antimicrobial prophylaxis is to sterilize the urine and
prevent infection.
The subject of sterile scars was contentious for many years
that sterile segmental scarring can be acquired only in extreme
hydrodynamic conditions amounting to obstruction, when VUR
is combined with severe bladder outflow obstruction resulting
in retention of urine, upper tract dilation, and sustained high
pressures within the urinary tract.
Sterile Reflux Nephropathy :
Parenchymal damage occurrs only when the urodynamic
abnormality was sufficient to cause a delay in renal excretion
rate (i.e., the presence of obstruction).
• . In a recent multicenter studies,
• antimicrobial prophylaxis did not decrease the risk of
recurrent UTI or the development of renal scarring in children
with low-grade reflux (grades I to III) compared with controls.
• However, for children with high-grade reflux (grades IV and V),
retrospective data have shown that reflux nephropathy is less
likely in children with high-grade VUR who present without
UTI
• In a study of 607 children with reflux diagnosed by VCUG
the subjects were randomized to antibiotic prophylaxis with
TMP-SMX or placebo
• The risk of recurrences was reduced by 50% in the treatment
group.
• The risk of renal scarring overall did not differ significantly
between the groups over 2 years.
• Also, the occurrence of a subsequent UTI with a TMP-SMX —
resistant organism was significantly increased in the treatment
group.
Prognosis
• Mortality related to UTI is exceedingly rare in otherwise
healthy children in developed countries
• Cystitis may cause voiding symptoms and require antibiotics,
but it is not associated with long-term, deleterious kidney
damage.
• The voiding symptoms are usually transient, clearing within
24-48 hours of effective treatment
• Morbidity associated with pyelonephritis is characterized by
systemic symptoms, such as fever, abdominal pain, vomiting,
and dehydration.
• Bacteremia and clinical sepsis may occur
• Dehydration is the most common acute complication.
Intravenous fluid replacement is necessary in more severe
cases
Renal Abscesses
Renal abscesses result from a severe infection that leads to
liquefaction of renal tissue; this area is subsequently
sequestered, forming an abscess.
They can rupture out into the perinephric space, forming
perinephric abscesses. When the abscesses extend beyond the
Gerota's fascia, paranephric abscesses develop
Abscesses that form in the renal cortex are likely to arise from
hematogenous spread, whereas those in the corticomedullary
junction are caused from gram-negative bacteria in conjunction
with some other underlying urinary tract abnormalities, such as
stones or obstruction.
Pyonephrosis •
Pyonephrosis refers to bacterial infection of a hydronephrotic,
obstructed kidney, which leads to suppurative destruction of the
renal parenchyma and potential loss of renal function. Because
of the extent of the infection and the presence of urinary
obstruction, sepsis may rapidly ensue, requiring rapid diagnosis
and management
• focal inflammation of the kidney (focal pyelonephritis) or renal
abscess. Any inflammation of the renal parenchyma may lead
to scar formation.
• Approximately 10-30% of children with UTI develop some
renal scarring; however, the degree of scarring required for
the development of long-term sequelae is unknown.
• Long-term complications of pyelonephritis are hypertension,
impaired renal function, and end-stage renal disease.