Download Urinary Tract Infection

Urinary Tract Infection In
Children
ETIOLOGY
Localization
• cystitis (infection localized
to the bladder)
• pyelonephritis (infection of
the renal parenchyma,
calyces, and renal pelvis)
• renal abscess(which may be
intrarenal or perinephric)
bacteria commonly causing
infection
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Escherichia coli
Klebsiella
Proteus
Enterococcus
Pseudomonas
Staphylococcus
saprophiticus
EPIDEMIOLOGY
• Approximately 8 o/o of girls and 2 o/o of boys
have a UTI by 11 years of age.
• The lifetime incidence of UTI in females is about
30 o/o compared to only 1 o/o in males.
• Approximately 75 o/o of infants younger than 3
months of age with bacteriuria are male
compared with only 10% berween 3 and 8
months of age.
• After 12 months of age, UTI in healthy children
usually is seen in girls.
Predisposing Factors
• short urethra in girls
• Uncircumcised male infants
• Obstruction to urine flow and urinary stasis:
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Anatomic abnormalities
Nephrolithiasis
Renal tumor
Indwelling urinary catheter
Ureteropelvic junction obstruction
Megaureter
Extrinsic compression
Pregnancy
Vesicoureteral reflux
CLI N ICAL MANIFESTATIONS
Neonate
• failure to thrive
• feeding problems
• fever
• direct hyperbilirubinemia
1 month to 2 years old
• feeding problems
• failure to thrive
• diarrhea
• vomiring
• unexplained fever
• At 2 years of age, children begin to show the
classic signs of UTI such as urgency, dysuria,
frequenry, and abdominal or back pain.
• The presence of UTI should be suspected in all
infants and young children with unexplained
fever and in patients of all ages with fever and
congenital anomalies of the urinary tract.
LABORATORY AND IMAGING STUDIES
• The diagnosis of UTI requires a culture of the
urine.
• Urine samples for urinalysis should be
examined promptly (within 20 minutes) or
refrigerated until culrured.
• Urine obtained by midstream, clean-catch technique
(for older children and adolescents) is considered
significant with bacterial growth of a single organism
of more than 100,000 colony forming units
(CFU)/mL.
• Urine obtained by catheterization is considered
significant with bacterial growth of more than 10,000
CFU/mL.
• Urine obtained by suprapubic aspiration is
considered significant bacterial growth of more than
1000 CFU/nL.
• Perineal bags for urine collection are prone to
contamination and are not recommended for urine
collection for culture.
Urinalysis
• Pyuria (leukocyturia of >10 white blood cells
[WBCs]/mm') suggests infection, but also is
consistent with urethritis, vaginitis,
nephrolithiasis, glomerulonephritis, and
intersticial nephritis.
• Urinary dipstick tests that combine both the
leukocyte esterase and nitrite have high
sensitivity and specificity for detecting a UTI.
Imaging
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Ultrasonography,
Voiding cystourethrogram (VCUG)
Radionuclide cystography
Renal nucleotide scans
Computed tomography (CT)
Magnetic resonance imaging (MRI)
• Ultrasound provides limited information about renal scarring
and is performed to exclude an anatomic abnormaliry.
• VCUG is the best imaging study for determining the presence
or absence of vesicoureteral reflux, which is ranked from
grade I (ureter only) to grade V (complete gross dilation of the
ureter and obliteration of caliceal and pelvic anatomy).
• A technetium- 99m DMSA scan can identify acute
pyelonephriris and is most useful co define renal scarring as a
late effect of UTI.
DIFFERENTIAL DIAGNOSIS
UTI
• signs of sepsis seen in
young children
• enteritis
• appendicitis
• mesenteric lymphadenitis
• pneumonia in older children
Dysuria
• pinworm infection
• hypersensitiviry to soaps or
derergents
• vaginitis
• Sexual abuse and infection
DIFFERENTIAL DIAGNOSIS
• The diagnosis of a UTI is confirmed by a
positive urine culture, although this does not
disringuish between upper tract and lower
tract infection.
• Localizatron of a UTI is important because
upper UTI is associated more frequently with
bacteremia and with anatomic abnormalities
than is uncomplicated cystitis.
DIFFERENTIAL DIAGNOSIS
Upper tract infection
• high fever,
• Costovertebral tenderness
• high erythrocyte
sedimentation rate (ESR)
• leukocytosis
• Bacteremia
WBC casts, inability ro concentrare urine
maximally, presence of antibody-coated
bacteria detecred by
immunofluorescence) and B2microglobulin excretion
lower tract infection
• Signs of cystitis
• low fever
TREATMENT
• Empirical therapy
• For an older child who does not appear ill
• For a child with suspected UTI who appears
toxic, appears dehydrated, or is unable to
retain oral fluids
• Children with high fever or other
manifestations of acute pyelonephritis
Duration of treatment
• Neonate :10 to 14 days with parenteral
antibiotics
• Older children with acute cystitis : 7 to 14 days
(5to7days) with an oral antibiotic
• Pyelonephritis : 7 to 14 days
COMPLICATIONS AND PROGNOSIS
• Bacteremia occurs in 2o/oto 5o/o of episodes
of pyelonephritis and is more likely in infants
than in older children.
• Focal renal abscesses are uncommon
complication.
• The relapse rate of UTI is approximately
25 o/o to 40o/o
• Most relapses occur within 2 to 3 weeks of
treatment.
• Follow-up urine cultures should be obtained 1 to 2
weeks after completing therapy to document sterility
of the urine.
• Prophylactic antibiotics should be administered until
the VCUG has been completed and the presence of
reflux is known.
• TMP-SMZ (2 mglkg TMP, 10 mglkg SMZ) and
nitrofurantoin (1 to 2 mglkg) given once daily at
bedtime are recommended as prophylactic agents,
which, in contrast to amoxicillin and cephalosporins,
are associated with low rates of developing antibiotic
resistance.
• Clinical follow-up for at least 2 to 3 years is
prudent, with repeat urine culture as
indicated.
• Some experts recommend that follow-up
urine cultures after recurrent cystitis or
pyelonephritis are obtained monthly for 3
months, at 3-month intervals for 6 months,
then yearly for 2 to 3 years.
PREVENTION
• Primary prevention is achieved by promoting
good perineal hygiene and managing undedying
risk factors for UTI, such as chronic constipation,
encopresis, and daytime and nighttime urinary
incontinence.
• Secondary prevention of UTI with antibiotic
prophylaxis given once daily is directed toward
preventing recurrent infections, although the
impact of secondary prophylaxis to prevent renal
scarring is unknown.
• Acidification of the urine with cranberry iuice
is not recommended as the sole means of
preventing UTI in children at high risk.
Vesicoureteral reflux (VUR)
• Vesicoureteral reflux (VUR) is the retrograde flow of
urine from the bladder to the ureter or up to the
kidney.
• Most VUR results from congenital incompetence of the
ureterovesical (UV) junction that matures through early
childhood.
• In a significant minority of children, structural UV
abnormalities exist that never resolve.
• VUR may be familial; 30o/o to 4o o/o of siblings of a
child with VUR also have VUR.
• VUR may also be secondary to distal bladder
obstruction or other urinary tract anomalies.
• VUR exposes the kidney to increased
hydrodynamic pressure during voiding and
increases the likelihood of renal infection due
to incomplete emptying of the ureter and
bladder.
• Reflux nephropathy refers to development
and progression of renal scarring.
CLI N ICAL MANIFESTATIONS
• VUR is most often identified during radiologic
evaluation following a UTI.
• The younger the patient with a UTI, the more
likely VUR is present.
• No clinical signs are reliable in differentiating
children with UTI with and without VUR.
DIAGNOSTIC STUDIES
• A voiding cystourethrogram (VCUG) or
radionuclide cystogram (NCG) should be
performed in all infants and children up to 6
years of age with a documented first UTI,
regardless of gender.
TREATMENT
• The presence of VUR is generally an indication
for longterm prophylactic antibiotic therapy
(trimethoprimsulfamethoxazole or
nitrofurantoin).
• Complications of reflux nephropathy are
hypertension and chronic kidney disease(
CKD).
• CKD is typically heralded by mild proteinuria and
involves development of focal and segmental
glomerulosclerosis and intersticial scarring.
• Indications for surgical repair of VUR are
controversial and have been made more complex by
the development of dextranomer/ hyaluronic acid
copolymer (Deflux procedure), which appears to be a
very successful minimally invasive correction of mild
to moderate VUR.