Transcript Urinary Tract Infections

By
Dr. Athal Humo
2015-2016
Objectives
• To understand the causative agents in U.T.I.
• To know the risk factors
• To study the main signs and symptoms of U.T.I.
in different ages in pediatrics
• To do the useful investigations.
• To out lines the treatment strategies
• To know how you prevent UTI.
Urinary tract infections (UTI) is common in
the pediatric age group. Early recognition and
prompt treatment of UTI are important to
prevent
progression
of
infection
to
pyelonephritis or urosepsis and to avoid late
sequelae such as renal scarring or renal failure.
UTI include :
• cystitis, infection localized to the bladder
• pyelonephritis, infection of the renal
parenchyma, calyces, and renal pelvis
• renal abscess, which may be intrarenal or
perinephric
Prevalence :
• UTI is more frequent in females than males at all
ages with the exception of the infantile period
• Approximately 5% of girls and 1% of boys have a UTI
by 11 years of age.
• In boys, most UTIs occur during the 1st yr of life;
UTIs are much more common in uncircumcised
boys.
• The prevalence of UTIs varies with age:
▫ During the 1st yr of life, the male : female ratio is 2.85.4 : 1.
▫ Beyond 1-2 yr, there is a female preponderance, with a
male : female ratio of 1 : 10.
Etiology
• UTIs are caused mainly by colonic bacteria. Gram-negative
enteric bacteria of the Enterobacteriaceae family cause most UTIs in
children of all ages. This includes: Escherichia coli, which are
responsible for 80–85% of all UTIs among children. Klebsiella,
Proteus, and Enterobacter spp. , and the other members of the
Enterobacteriaceae family are less frequent causes of UTI.
• Less commonly, Pseudomonas aeruginosa, Gram-positive
organisms such as Enterococcus and Staphylococcus, and Group B
Streptococcus also cause UTI in children. Group B Streptococcus is
almost exclusively seen as a cause of UTI in neonates, whereas
Staphylococcus saprophyticus is typically seen in adolescent.
Staphylococcus aureus is an uncommon cause of UTI and may be
the result of hematogenous spread to the kidney. Infection with S.
aureus often results in focal renal lesions, such as intrarenal and
perinephric abscesses.
• Adenovirus infections also can occur, especially
as a cause of hemorrhagic cystitis and it more
common in male.
• fungal and parasitic and other viral infections
of the urinary tract are also encountered
especially
in
immunocompromised
and
susceptible subpopulations.
In neonates, infection of the urinary tract is
assumed to be due to hematogenous rather than
ascending infection. This etiology may explain the
nonspecific symptoms associated with UTI in
these patients.
Risk Factors For UTI :
1.
2.
3.
4.
5.
6.
7.
8.
Female gender
Uncircumcised male
Vesicoureteral reflux
Toilet training
Voiding dysfunction
Obstructive uropathy
Urethral instrumentation
Wiping from back to front in
girls
9. Bubble bath
10. Tight clothing
(underwear)
11. Pinworm infestation
12. Constipation
13. Anatomic abnormality
14. Neuropathic bladder
15. Sexual activity
Management:
There are four main steps in the clinical management of
UTIs in childhood:




Diagnosis of UTI
Determination of the site of the infection
Search for the cause of the UTI
Treatment
 Diagnosis of UTI
Diagnosis of UTI depend
presentations & investigations.
on
Manifestations of UTI vary with:
• age
• site of infection within the urinary tract
• severity of infection.
clinical
HISTORY
Urinary tract infections may occur
without symptoms, with symptoms that
direct attention to the urinary system, or
with symptoms that divert the attention to
other organ systems


Thus, the clinician must maintain a
high index of suspicion for UTI,
particularly in infants and young children
with vague or nonspecific infectious
symptoms
In neonates & 1st 3 mo
 lethargy, irritability, poor feeding, vomiting,
diarrhea, apnea, fever or hypothermia, and
prolonged jaundice are all frequent findings.
Although very nonspecific and often more
suggestive of acute gastroenteritis than UTI, the
diagnosis is rarely missed, since a urinalysis and
urine culture are routinely part of the septic
screen evaluation performed in this age group.
3mo to 3years old:
 Fever, constitutional complaints, abdominal
discomfort, and GI symptoms are common in
pyelonephritis.
 Whereas frequency and irritability on
micturition are often the only indicators of
cystitis.
In older children who are both verbal
and toilet trained
the diagnosis becomes more straightforward.
 With cystitis, all or some combination of the
classic signs of dysuria, frequency, urgency,
suprapubic discomfort, daytime or nocturnal
enuresis, and perhaps low-grade fever are present.
 With pyelonephritis, high fever, clinical
toxicity, vomiting, and abdominal and/or flank pain
are most common. These upper tract symptoms may
or may not be accompanied by lower tract
complaints.
PHYSICAL FINDINGS
• Findings in infants who have a UTI may be normal except for
fever and irritability.
• Older children may report direct tenderness on palpation of the
abdomen, suprapubic area, or costovertebral angle (CVA)
(Murphy test), if -ve is not reliable to exclude parenchymal
infection in young children. However, when present it is helpful
and should be performed as part of the physical examination of
all children suspected of UTI.
• Patients who have urinary tract obstruction may have palpable
abdominal masses.
• Dribbling, poor stream, or straining to void
• Examine external genitalia for signs of irritation, pinworms,
vaginitis, trauma, phimosis or meatal stenosis .
• Hypertension should raise suspicion of hydronephrosis or renal
parenchyma disease.
 Localization of the UTI
The differentiation between upper (pyelonephritis)
and lower (cystitis) UTI is very important. It
particularly has major clinical implications in young
children. The risk of renal scarring is significant with
pyelonephritis, and not a concern with cystitis.
Therefore the management (investigations, antibiotic
used, length of therapy) is totally different for
pyelonephritis and cystitis. The location of the site of
infection is based on a combination of clinical,
laboratory and imaging findings.
In
the
cystitis
syndrome,
the
bladder/voiding symptoms is common such as
frequency, pain with micturition, suprapubic
discomfort, difficulty in voiding (retention) or
hesitancy, urgency, and enuresis.
Back and suprapubic pain, as well as fever,
may occur. Gross hematuria (without casts) is a
common finding. Bacterial infection, particularly
E.coli cause hematuria in girls whereas in boys,
adenovirus infection occurs frequently. The
urine culture will reveal the offending organisms
in the former instance and will be sterile in the
latter
In
the
classic
pyelonephritis
syndrome, the patient has generalized
symptoms that may include a toxic appearance,
high fever, chills, vomiting, diarrhea, and
abdominal pain in addition to the urinary outlet
symptoms
The urinalysis usually reveals typical pyuria and
bacteria, and often, white blood cell (WBC) casts
are observed
Investigation
The definitive diagnosis of UTI is critical and
involves a number of important considerations. False
positive diagnosis may lead to unnecessary treatment,
as well as invasive and expensive clinical and
radiographic examinations. False positive diagnoses
are frequent in infants and small children because
reliable collection of urine specimens without
contamination is difficult. On the other hand, false
negative diagnosis dramatically increases the risks of
renal scarring and its attendant morbidity:
hypertension, complications of pregnancy in women,
and end stage renal disease.
 Urinalysis
Urine color and smell: Turbid urine may be an
indication of pyuria and UTI. abnormal smell may be
suggestive of onset of UTI but it is a poor indicator of
screening for UTI.
Urine microscopy:
▫ Bacteriuria, Detection of any bacteria in the
uncentrifuged urine slide stained with Gram stain has
been used as the gold standard for presumptive
diagnosis of UTI.
▫ Pyuria, or light-microscopy visualization of more than
10 WBCs/hpf in centrifuged urinary sediment is
considered presumptive evidence of UTI.
Leukocyte esterase:
Testing for leukocyte esterase may overcome some of
the limitations of urinary microscopy in identifying
leukocyturia. Leukocyte esterase is present in the
neutrophils and can be assayed in the urine by dipstick
strips. False-negative tests may be caused by the
presence of ascorbic acid, high urinary protein,
glycosuria, urobilinogen, gentamicin, nitrofurantoin,
cephalexin, and boric acid. False-positive tests can
results from the presence of imipenem and clavulanic
acid in the urine.
Nitrite test:
This test is based on the fact that the bacterial enzyme
nitrate reductase can convert urinary nitrate to nitrite,
which can be detected by several chemical methods.
 Urine culture
 Culturing urine is gold standard for confirming the
diagnosis of UTI.
 Methods to Obtain Urine Specimens:
1. The gold standard for obtaining urine in an infant is
by suprapubic aspiration. By using this method
the risk of contamination is very low. Complications
are rare with the use of ultrasound guidance.
2. Urinary catheterization is also a very reliable
method for obtaining urine without contamination
3. Clean-catch mid-stream urine specimens can be
collected in toilet-trained children.
4. Urine collected in bags is generally not suitable
for culture because of the high incidence of
contamination, If a scaled adhesive bag is to be
used for collection of urine sample, the following
conditions should be considered for better results :
The skin should be dried thoroughly after cleaning the
periurethral area
The child should be kept in an upright position to prevent
having urine come in contact with the skin or entering the
vagina
The bag should be removed immediately after the child
has voided
Cultures from bagged urine specimens are significant
only if there is no growth.
• The urine should examined withen 20 min, or
refrigerated immediately at +4c until cultured to
prevent growth of contaminating bacteria and it
is essential that this temperature be maintained
during transport.
• The interpretation of culture depends on the :
▫
▫
▫
▫
Method of urine collection
Clinical background (signs & symptoms)
Number of colony forming units per ml
Result of urinalysis
• If urine obtained by suprapubic aspiration, any growth is
considered significant.
• In catheterized specimens, the cutoff level suggested is
50,000 CFU/ml.
• In midstream urine sample, If the culture shows >100,000
colonies of a single pathogen, or if there are 10,000 colonies and
the child is symptomatic, the child is considered to have a UTI.
• In collection bag, can be useful, particularly if the culture is
negative, A positive culture may reflect a contaminant,
particularly in girls and uncircumcised boys. In such cases, if
the urinalysis result is positive, the patient is symptomatic, and
there is a single organism cultured with a colony count greater
than 100,000, there is a presumed UTI. If any of these criteria
are not met, confirmation of infection with a catheterized
sample is recommended.
 Imaging Studies
• The goal of imaging studies in children with a UTI is to identify:
▫
▫
▫
▫
anatomic abnormalities
active renal involvement
renal scaring
assess renal function .
• Ultrasonography, VCUG, radionuclide cystography, renal nucleotide
scans, and CT or MRI can be used for anatomic and functional
assessment of the urinary tract. Ultrasound provides limited
information about renal scarring and is performed to exclude an
anatomic abnormality. VCUG is the best imaging study for determining
the presence or absence of vesicoureteral reflux. A technetium-99m
DMSA scan can identify acute pyelonephritis, but is most useful to
define renal scarring as a late effect of UTI.
DMSA scan
The NICE (National Institute for Health and
Clinical
Excellence,
UK)
guidelines
recommendations include upper tract imaging with a
DMSA scan for :
1. all <6 mo with a UTI
2. all children <3 yr with an:
 atypical UTI ((sepsis, non–E. coli UTI, suprapubic mass,
elevated serum creatinine, hypertension).
 recurrent UTI.
3. for children >3 yr, a DMSA scan is recommended
only for recurrent UTI.
Indication of renal US:
1. In children with their 1st episode of clinical
pyelonephritis (those with a febrile UTI, or, in
infants, those with systemic illness)
2. positive urine culture, irrespective of
temperature.
A sonogram of kidneys and bladder should be
performed to assess kidney size, detect
hydronephrosis and ureteral dilation, identify the
duplicated urinary tract, and evaluate bladder
anatomy.
VCUG
The most common finding is vesicoureteral reflux,
which is identified in approximately 40% of patients
CT scan
CT is another diagnostic tool that can image
acute pyelonephritis, but clinical experience with
DMSA is much greater, and CT scans have more
radiation.
 Treatment
The aims of antimicrobial treatment for urinary
tract infection are:
 To clear the acute infection
 To prevent urosepsis
 To reduce the likelihood of renal damage.
Acute cystitis
should be treated promptly to prevent possible progression to
pyelonephritis.
• If the symptoms are severe, presumptive treatment is
started pending results of the culture.
• If the symptoms are mild or the diagnosis is doubtful,
treatment can be delayed until the results of culture are known,
and the culture can be repeated if the results are uncertain.
If treatment is initiated before the results of a culture and
sensitivities are available, a 5-7day course of therapy with:
 trimethoprim-sulfamethoxazole or trimethoprim is effective
against most strains of E. coli.
 Nitrofurantoin (5-7 mg/kg/24 hr in 3-4 divided doses) also is
effective and has the advantage of being active against
Klebsiella and Enterobacter organisms.
 Amoxicillin (50 mg/kg/24 hr) also is effective as initial
treatment but has no clear advantages over sulfonamides or
nitrofurantoin.
Acute pyelonephritis
 10- to 14-day course of broad-spectrum antibiotics capable of reaching
significant tissue levels is preferable.
 Indication of hospitalization for IV rehydration and IV antibiotic
therapy include:
1.
2.
3.
4.
5.
Children who are dehydrated
Vomiting.
are unable to drink fluids.
are ≤1mo of age.
in whom urosepsis is a possibility.
 Parenteral treatment with:


ceftriaxone (50-75 mg/kg/24 hr) or cefotaxime (100 mg/kg/24 hr)
ampicillin (100 mg/kg/24 hr) with an aminoglycoside such as
gentamicin (3-5 mg/kg/24 hr in 1-3 divided doses) is preferable.
 Treatment with aminoglycosides is particularly effective against
Pseudomonas spp, and alkalinization of urine with sodium
bicarbonate increases its effectiveness in the urinary tract.
 Oral therapy:
Oral 3rd-generation cephalosporins such as cefixime
considered the treatment of choice for oral outpatient
therapy.
Nitrofurantoin should not be used routinely in children
with a febrile UTI because it does not achieve significant
renal tissue levels.
 A urine culture 1 wk after the termination of treatment of a
UTI ensures that the urine is sterile but is not routinely
needed.
 Children with a renal or perirenal abscess or with infection
in obstructed urinary tracts can require surgical or
percutaneous drainage in addition to antibiotic therapy and
other supportive measures.
Recurrent Urinary Tract Infections
 In a child with recurrent UTIs, identification of
predisposing factors & treated it is beneficial, as voiding
dysfunction, Some children with UTIs void
infrequently, and many also have severe constipation .
Counseling of parents and patients to try to establish more
normal patterns of voiding and defecation is most important
in controlling recurrences.
Prophylaxis against reinfection, using TMP-SMX,
trimethoprim, or nitrofurantoin at 30% of the normal
therapeutic dose once a day, is one approach to this problem.
Prophylaxis with amoxicillin or cephalexin can also be
effective, but the risk of breakthrough UTI may be higher
because bacterial resistance may be induced.
 Other more high risk conditions for
recurrent UTIs that might need long-term
prophylaxis include neurogenic bladder, urinary
tract stasis and obstruction, reflux, and calculi.
 The main consequences of chronic renal
damage caused by pyelonephritis are arterial
hypertension and end-stage renal insufficiency;
when they are found they should be treated
appropriately .
Prevention of UTI:
•
•
•
•
•
•
•
•
•
Avoid constipation.
If your child has any problems with worms let the doctor know.
Wiping should be done in a front to back direction.
It is better to take a shower rather than a bath. Always avoid irritating
soaps and bubble baths.
Emptying the bladder propably is very important.
Always encourage your child to drink as much as possible during the day,
and to Empty the bladder propably last thing at night.
Correct underwear, avoid tight underpants or pantyhose. They prevent
air from circulating freely and encourage the warm, moist environment
which favors infection.
When taking antibiotics, the full course must be taken at the time
required.
Any proplems such as burning when passing urine, going to the toilet
frequently, or blood in the urine should be reported to the doctor.