Transcript URINARY TRACT INFECTIONS IN CHILDREN

URINARY TRACT INFECTIONS
IN CHILDREN
Assist. prof. dr. Magdalena Stârcea
IVth Pediatric Clinic

Background: Urinary tract infections (UTIs) are common in
the pediatric age group. Early recognition and prompt
treatment of UTIs are important to prevent progression of
infection to pyelonephritis or urosepsis and to avoid late
sequelae such as renal scarring or renal failure.

Infants and young children with UTI may present with few
specific symptoms. Older pediatric patients are more likely to
have symptoms and findings attributable to an infection of the
urinary tract.

Differentiating cystitis from pyelonephritis in the pediatric
patient is not always possible, although small children who
appear ill or who present with fever should be presumed to
have pyelonephritis if they have evidence of UTI.

TERMINOLOGY. CLASSIFICATION
I. Urinary tract infection - is the common term for a
heterogeneous group of conditions involving pathogenic
bacterial colonization of the urinary tract at any level of the
urinary meatus renal cortex , followed by the elimination of
germs in the urine. Colonization may be transient or
permanent .
II . Asymptomatic bacteriuria: significant bacteriuria
detected by screening in apparently healthy population . It is
commonly seen in girls of school age.
III . Bacteriuria is pathognomonic feature of urinary infection , a
term used for the presence of bacteria in urine obtained optimally
by bladder catheterization or suprapubic aspiration puncture .
- significant bacteriuria is defined as Kass > 105CFU / ml ( CFU =
colony forming units ) in urine obtained by the methods of
peripheral collecting (urinary stream)
- Johnson describes more complex benchmarks with practical
applications for assessing significant bacteriuria : bacteriuria
than 10 ² CFU / ml in children catheterized bladder , or any
amount of colonies urine specimens collected by suprapubic
aspiration .
IV . Symptomatic UTI is defined as significant bacteriuria
associated with suggestive symptoms (dysuria, urinary urgency,
urinary frequency, with or without fever and back pain) .
It can manifest as:
Pyelonephritis - bacterial infection of the renal parenchyma
and intrarenal urinary way and is accompanied by significant
bacteriuria, bacteremia, pyuria, hematuria sometimes .
Cystitis : inflammation of the bladder, manifested by dysuria ,
urinary frequency, urinary urgency. Fever is not present .
V. Chronic pyelonephritis is a pathological condition which
involves renal scarring. If pyelonephritis associated with
vesicoureteral reflux (especially intrarenal reflux ), the term used is
reflux nephropathy. Acute inflammatory changes are found in high
UTI and disappear on average 6 months after acute infectious
episode .
VI. Response to treatment
Recovery is characterized by the loss of bacteriuria following
treatment.
Relapse : characterized by persistent bacteriuria (same bacterial
species) after adequate treatment of the infection; is commonly
associated with a structural abnormality of the urinary tract or stones
.
Reinfection: characterized by successive episodes of symptomatic
and asymptomatic episodes of urinary tract infection. This episodes
are caused by different bacterial species or serotypes and reflects a
defect in the local defense mechanisms .
Persistent infection : characterized by the presence of significant
bacteriuria during and after treatment.
EPIDEMIOLOGY:
 UTI has males predominance in the first trimester of life (up to 3
months). Uncircumcised males have a higher incidence than
circumcised males. Uncircumcised male infants have a higher
incidence of UTI than female infants.
 Except neonatal period, UTIs are more frequent in females than
males at all ages.
 International studies show the highest incidence peak of the first
episode of uper UTI between 0 and 2 years. The peak incidence of
the first lower episode of UTI (boys and girls ) is between 2-4 years.
 Asymptomatic bacteriuria is more common in girls of school age.
 Nosocomial urinary infection occurs only in the case of investigating
urinary malformation in children substrates .
 After Nelson (18th edition , 2007) the cumulative incidence is 2.5 %
for both sexes. ITU occurs 3-5 % of girls and 1% of boys
 The American Academy of Pediatrics (Bergman DA , Baltz RD,
2009) recognizes a febrile urinary tract infection incidence of 6.5 %
to girls and 3.3 % for boys .
ETIOLOGY:
 Escherichia coli causes 75-90 % of UTI in children.
 Other common bacterial etiology of UTI are Klebsiella pn . ,
Proteus (30% of boys cystitis ), Staphylococcus saprophyticus
(urinary infections in adolescents of both sexes and in the
neonate).
 In the neonatal period, especially in premature urinary infections
are determining by hematologycal way, and etiology are
dominated by E. coli, Salmonella , Enterobacter , Klebsiella.
 In patients with congenital abnormalitiesof renal or urinary tract
function may occur urinary infection caused by bacterial low
virulent in normal conditions (Pseudomonas aeruginosa ,
Staphylococcus aureus or epidermis, Hemophilus influenzae ,
Group B sterptococi , adenovirus ) .
 Acute cystitis may be caused by adenoviruses , especially male
school , manifested by fever, dysuria and terminal hematuria .
 In adolescents isolated urethritis manifested with dysuria is
generated by microorganisms such as Chlamydia trachomatis ,
Neisseria gonorheae , Mycoplasma genitalium , or herpes
simplex virus.
PATHOGENESIS - UTI is an interaction between
→ host factors
→ invading microorganism
 Way of infection
a) descending
- Common in the new born
- Unusual for onother age
- Older children are involve virulent microorganisms such:
S.aureus, P. aeruginosa, Serratia, KB
b) ascending (colonization retrograde from the urethral orifice)
- Germ involved found in bowel flora
- Serotypes with virulence special for urothelium
- Favored by malformation
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Host factors:

Anatomical abnormalities
Physiologically - adhesion and proliferation of germs is prevented by
washing process during urination (local defense mechanism ).
Urinary abnormalities may interfere with defense mechanisms
Patients with ITU - 40-50% defects detectable radiographically
- 30 % have RVU
Other malformations : - obstruction at different levels of urinary
- ureterocel
- urinary stones , predispose to stasis/infection.
- foreign bodies (catheters) facilitate infection
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Uroepithelial adherence in patients with recurrent UTIs without
malformation, urinary cells have a high density of receptors on
their surface → persistence + proliferation of germs.
Mechanisms of adhesion is unclear, are involved:
some blood group antigens present on cells and secreted from the
cell surface
deficit of Se IgA or lysozyme

Bacterial factors:
Virulence elements:
- Bacterial outer membrane is made of - proteins, lipids ,
lipopolysaccharides .
- Bacterial endotoxin (AgO, LPS structure) → responsible for
systemic reaction (fever, shock )
- Bacterial capsule is composed of LPS acid (K antigen with important
role in bacterial virulence)
- Adhesion of E. coli to uroetheliu - essential for persistence in the
urinary tract, a phenomenon mediated by receptors (pili or fimbriae)
- Virulence of E. coli is signed by associating other bacterial factors:
- Production of hemolysin
- Production of aerobactină
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CLINICAL PRESENTATION
Urinary tract infection in children has a wide spectrum of
manifestations, ranging from asymptomatic bacteriuria or subtle
manifestations, of revision (enuresis , urgency of micturition ) to
the clinical picture of toxic-septic shock (in newborn and
premature.
1. Neonate: nonspecific symptoms such as weight loss, vomiting,
flatulence, thermal instability, frequently hypothermia, poor
feeding, respiratory distress, prolonged jaundice, Failure to
thrive. May be complicated by sepsis with positive blood cultures
and secondary dissemination.

2. Perioada infancy : clinical picture is nonspecific
- septic type fever, poor feeding, vomiting
- irritability, parenteral diarrhea, flatulence, jaundice
- strong-smelling urine
3. Preschoolers and schoolers :
- Signs of cystitis ( dysuria, urinary frequency, urinary urgency)
- Nocturnal enuresis or diurnal (recently installed)
- Signs of acute pyelonephritis (fever, vomiting, back pain or
flank pain, macroscopic hematuria)
- Strong-smelling urine
Acute renal failure is rarely reported in association with
first acute pyelonephritis. If there happend betrays a malformation.
Some infections with Proteus can generate stones (Proteus
cleaves urea into ammonia and CO2, with alkalinization of urine
and precipitation of salts, with formation of calculi) .

DIAGNOSIS :
Objectives:
- Confirm the UTI
- Identification of malformations
- The location of infection
Urine analysis
a) urine analysis :
- Leucocyturia ( > 10WBC/ )
Attention to other situations with leucocyturia without UTI :
- dehydration
- vaginitis
- urethral irritation, stones
- tubular acidosis
- interstitial nephritis, GN, polycystic kidney disease
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b ) screening tests :
- Nitrite test : bacterial nitrate reductase converts urinary
nitrates into nitrites. False negative test is if the bacteria does
not have nitrate reductase or in case with polyuria
- Urinary density may be decreased in chronic pyelonephritis
- Proteinuria is found in small quantities
- Microscopic hematuria occurs frequently (sometimes
macroscopic)
c ) urine culture
Method for collecting urine is dependent the age :
- Older children, teens - from medium urinary jet, after rigorous
local toilet. This is the method most frequently used, but the
chance of bacterial contamination of the urine sample is great.
- Infants and toddlers - by peripheral collecting vessels after
thorough cleaning of the perineal area and pasting container. It
has a high risk of contamination, time being near the rectum , but
it is no invasive .
- In infants - by catheterisation - uncontaminated urine sample
- In newborns and infants - suprapubic puncture is most simple,
quick and safe method of urine collection .
Microbiological Diagnosis Criteria
classical interpretation is the Kass criteria: significant
bacteriuria - over than 105UFC/ml in urine obtained by
peripheral method
-
Johnson describes more complex benchmarks with practical
applications for assessing significant bacteriuria :
Bacteriuria than 10 ² CFU / ml in children with catheterized
bladder, or
Any colonies from urine specimens collected by suprapubic
aspiration, or
Over 105CFU/ml in urine collected by means of peripheral

B. Blood analyses
- CBC - inflammatory anemia, leukocytosis with netrophils
- Acute phase reactants: ESR, Fg; PCR (positive in
pyelonephritis )
- Nitrogen retention may occur in newborn, small infants and in
cases that have a pre-existing malformation substrate
- Positive blood cultures (in neonates, infants, dystrophic,
immunocompromised)
Recently, techniques described for immunological diagnosis of
renal involvement in urinary tract infection. β2 microglobulin, IL 6,
procalcitonin, Tamm Horsfall protein, LDH enzyme complex seems
to have a important role in the differentiation of lower and upper
urinary tract infection and to determinate the severity of
pathological lesions of UTIs.
C. Imaging evaluation
Purpose: - discovery malformations
- discovery renal scars
- evaluation of renal function
Imaging evaluation is considered mandatory to:
- All children less than 5 years with recurrent UTIs
- UTI in infants
- All boys with recurrent UTIs, regardless of age
- All cases of recurrent UTIs
a) Ultrasonography
- noninvasive
- Reveals dimensions renal system changes pioelocaliceal ,
stones
- Practice regardless of the patient's condition and GFR
b ) Voiding cystourethrogram (VCUG) detects urethral and
bladder anatomy, UPV and vesicoureteral reflux (VUR).
- The only way (usual) for the diagnosis of VUR
- Useful in the diagnosis of posterior urethral valve (elective endoscopy bladder that can be practiced valve resection too)
- After at least 3 weeks after the sterilization of urine
c ) Intravenous urography (IVU) view size of kidneys, renal
scarring , pielocaliceal system and function, stones
- Is contraindicated in renal failure
d ) Exploring radionuclide
* Tc99 DTPA - provides data on renal function
* Tc99 DMSA – for renal scarring
Imaging investigations algorithm is :
• ultrasound - first line
• minimum radioisotope examination at 10-14 days
for diagnosis renal scarring of acute infection
• at 6 months DMSA for chronic renal scarring
• voiding cystourethrogram within 3-6 weeks after
infection sterilization
TREATMENT:
The therapeutic measures depend on the localisation of the
infection, the age of the patient.
Acute pyelonephritis:
hospitalization, especially in infants and small children
iv antibiotics:
I. cephalosporins (IIth/ IIIth generation)
- Cefamandole 50-150 mg / kg / day
- Ceftazidime 50-100 mg / kg / day
- Cefuroxime 50-100 mg / kg / day
- Ceftriaxone 50-100 mg / kg / day
II . aminoglycoside ( netilmicin ) 5 mg / kg / day
! Attention to renal toxicity
Favorable evolution occurs in 48-72 hours.
Urine culture control is performed in 48 - 72hours.
After 3-5 days you can switch to oral therapy if:
- Toxic signs disappeared
- Clinical improvement occurred
- Germ is sensitive to oral antibiotics
The duration of the treatment = 10-14 days
In case of lack of response may suspicion :
- resistance to antibiotics
- urinary tract obstruction
- presence of complications (renal abscess)
Acute cystitis - oral therapy:
- Trimethoprim 5-8 mg / kg / day
- Amoxicilin+clavulanic acid (40 mg / kg / day)
- Nitrofurantoin 5-7 mg / kg / day
- Quinolones in adolescents
The control urine cultures performed 48 hours
Duration of treatment = 5-7 days
UTI in newborn
- emergency hospitalization (risk of sepsis)
- iv antibiotic therapy starts quickly after hospitalisations and
continued until the blood and urine normalization
- antibiotic dosage is based on gestational age in preterm
newborns and glomerular filtration rate for newborn
- after clinic normalization malformation will fund evaluate
- in the absence of malformations or complications AB stops
after 10-14 days
UTI recurrence prevention
- Recurrence occurs in 40-50 % of cases even in the absence of
malformations.
- Prophylactic therapy is applied in single dose at bedtime , 1/ 4
to 1 /3 of the loading dose .
* Nitrofurantoin 1-2 mg / kg / day
* Trimethoprim 2 mg / kg / day
* Second generation cephalosporins (Cefaclor 5-10mg/kg/zi)
Prophylactic therapy is applicable to:
- Recurrent UTI
- UTI with malformation
- UTI + urinary stones
- UTI + neurogenic/unstable bladder
Asymptomatic bacteriuria
- In 40-50 % of cases sterilized
without treatment
- There is no deterioration of renal
function
Hygienic-dietary regime in UTI:
- Rich fluid regime
- Regular urination
- Emptying of the bladder
- Combating constipation
References:
1. O. Brumariu, Mihaela Munteanu, Infecția tractului urinar, în Hematologie
și nefrologie pediatrică, elemente practice de diagnostic și tratament,
editura Junimea, Iași, 2008, cap. 10, pag. 283 – 293.
2. Brumariu O, Munteanu M, Gavrilovici C, Infecţia tractului urinar, în
Ciofu E, Ciofu C, Pediatria - tratat, ediţia I, Bucureşti, 2001, cap. 11,
pag. 711- 718.
3. Nelson textbook of pediatrics - 18 ed. Behrman RE, Kliegman RM, Jenson
HB: Urinary Tract Infections, cap. 538, pag. 2223 – 2227, Saunders
Elsevier, 2007.
4. Rubin HR, Cotran RS, Tolkof – Rubin N.E. Urinary Tract Infection,
Pyelonephritis, and Reflux Nephropathy, BRENNER & RECTOR’S THE
KIDNEY, ediția 9, Saunders Elsevier, 2012; cap. 34:1203 – 1238.
5. Rees L., Brogan P., Bockenhauer D., Webb N., Urinary Tract Infections, în
Pediatric Nephrology, Oxford Specialist Handbooks in Pediatrics, second
edition, cap. 4, pag. 75 - 90.
6. Stârcea (Buhuș) Iuliana, Infecția de tract urinar la copil. Probleme de
diagnostic și tratament, teză de doctorat, Iași, 2011.
7. Stârcea Magdalena, Mihaela Munteanu, Gabriela Coman, Cristiana
Dragomir, O. Brumariu: Infecția urinară la copil. Aspecte ale
diagnosticului bacteriologic, Rev. Med. Chir, Iași, 2008; 112(4):932-937.
8. Svanborg C., Godaly G., Urinary tract infections revisited, Kidney
International (2007) 71, 721–723.