Download Urinary Tract Infections in Children

Urinary Tract Infections in
Children
Diagnostic Imaging based on Clinical
Practice Guidelines
Emily D. Kucera, M.D.
Assistant Professor, UMKC
Learning Objectives
• State prevalence, associations, and
consequences of febrile UTI’s in children
• Discuss imaging options and timing of
procedures
• Discuss classification systems used in radiologic
reports
• Review variations of Clinical Practice Guidelines
from reputable institutions- will discuss CMH
guidelines and include others in handout.
Febrile UTI’s
Most common serious bacterial infection
occurring in infancy and childhood
Affects at least 3.6% of boys, 11% of girls
10-30% of children with febrile UTI’s will
develop renal scarring
Diagnosis of UTI
Combination of clinical features and
presence of bacteria in urine > 10⁵ cfu/ml
Acute pyelonephritis = UTI + fever
• > 38℃ (100.4℉) - most common in
infants
Cystitis = symptoms of dysuria, frequency,
suprapubic pain in toilet-trained child
Urinary Tract Infections in
Children
Prevalence of positive culture in children 0-21
years 8.8 - 14.8%
Males < 1 year (3%); males > 1 year (2%)
Females < 1 year (7%); females > 1 year (8%)
50-91% of children with febrile UTI’s are found
to have acute pyelonephritis
All infants < 8 weeks of age with fever should be
suspected of having an upper tract
infection/pyelonephritis
Organisms Associated with
UTI’s in Children
_
+
•
•
•
•
•
Escherichia coli - Most common organism; causative agent in > 80% of 1st UTI
Klebsiella species - 2nd most common organism. Seen more in young infants
Proteus species - May be more common in males
Enterobacter species - cause < 2% of UTI’s
Pseudomonas species - cause < 2% or UTI’s
•
•
•
•
Enterococci species- Uncommon > 30 days of age
Coagulase-negative staphylococcus - Uncommon in childhood
Staphylococcus aureus - Uncommon > 30 days of age
Group B streptococci - Uncommon in childhood
Risk Factors for UTI’s
Male
Uncircumcised < 1 yr (5-20 x higher risk than
circumcised males)
All < 6 months
Female
< 1 yr
non-African American race
fever > 39℃ (102.2℉)
Atypical UTI’s
•
•
•
•
•
•
Seriously ill
Poor urine flow
Abdominal or bladder mass
Raised creatinine
Septicemia
Failure to respond to treatment within
48 hrs
• Infection with non- E. coli organisms
“Seriously Ill”
Recurrent UTI’s
• 2 or more episodes of acute
pyelonephritis / upper urinary tract
infection
• or
• 1 episode of acute pyelonephritis + > 1
episode of cystitis
• or
• > 3 episodes of cystitis/lower urinary
tract infection
Recurrent UTI’s
Girls are more prone to recurrences with
age
Children who present early in life with UTI
are more prone to recurrences
¾ of children presenting < 1 year will have
recurrences
> 1 year of age ~ 40% of girls, 30% of boys
Overall incidence of UTI recurrences after
pyelonephritis is 20.1%
Asymptomatic Bacteriuria
Most common in boys in early infancy
1.6% boys < 2 months
affects 0.2% in school age boys
Girls have lower rates until 8-14 months
1.5 - 2% in school age girls; peak
prevalence 7-11 years of age
Dysfunctional Elimination Syndromes
(DES)
Constipation- seen in 50 % of DES and VUR
• May induce uninhibited bladder contractions
• Rectal distention causes bladder distortion
causing detrusor dyssynergism and ureteral
valve incompetence
Bladder instability
Infrequent voiding (< 4 times/day)
Contributes to UTI’s and slower resolution of
reflux
Associations with UTI’s
Dysfunctional Elimination Syndromes
(DES)
67% of girls with DES develop UTI’s
40% of girls with UTI’s have DES
20% of girls with DES have reflux
A 6 month old female has had 3
UTI’s. Which of the following is the
best approach?
A. No imaging
needed
B. US + VCUG
C. MRI
D. DMSA scan
63%
25%
13%
0%
A.
B.
C.
D.
Imaging Procedures
• Ultrasound - detect renal anomalies, dilatation,
renal sizes, bladder abnormalities, ureteral
dilatation
• VCUG - Voiding Cystourethrogram- assess for
vesicoureteral reflux, bladder volumes, bladder
abnormalities, urethral anatomy
• DMSA Scintigraphy- assess for pyelonephritis
and renal scarring
• Radionuclide Cystogram - assess for VUR;
used infrequently at CMH
Abnormal Ultrasound
Findings
Dilatation of at least 1 calyx
Anteroposterior (AP) diameter of the renal
pelvis > 7 mm; ureteral diameter > 5 mm
Focal scarring
Difference of > 10% of length between
kidneys or renal length > 2 standard
deviations above mean
Bladder abnormality
Normal
Hydronephrotic MCDK
Society of Fetal Urology Classification of
Prenatal and Postnatal Hydronephrosis
1
2
3
4
Duplicated Collecting
Systems
• Duplication of renal pelvis and ureter is one of the
most common anomalies of the urinary tract
• Partial - range from bifid renal pelvis to 2 ureters
joining anywhere proximal to uterovesical junction
• Complete - 2 separate ureters with the upper pole
ureter draining more caudal and medial than the
lower pole ureter = ectopia (Weigert-Meyer rule)
• Ureteral duplication is of no clinical significance
unless it is complicated with ectopia, VUR, UTI, or
obstruction
Duplicated Collecting Systems
Non-dilated
Dilated
Voiding Cystourethrogram
• Requires bladder catheterization:
• 8 Fr feeding tube (No balloon)
• Lidocaine gel used on majority of patients
• Local analgesia
• Dilates meatal opening
• Radiation:
• Decreased dose with pulse and digital techniques
• 1-3% risk of UTI
Need for Sedation
• Sedation not needed in the vast majority of the
cases
• CMH Guidelines for sedation follow the AAP
and ASA (Anesthesia) Guidelines
• If need for anxiolysis, please directly
communicate with the Radiologist who will be
performing the exam at the time of scheduling
• Child Life personnel available at the Main and
the South Campuses.
Vesicoureteral Reflux
International Reflux Grading System of
VUR
Bilateral Grade 2
Grade 1
Grade 3
Vesicoureteral Reflux
Incidence 20-40 % of children presenting
with UTI
Girls 17-34%
Boys 18-45%
Increased incidence if family history of
VUR
• Parent to Child: up to 66%
• Siblings: up to 34%
Overall prevalence in general population
1-3%
Prevalence of VUR by Age
• Prevalence in 54 studies of UTI in Children
Prevalence of VUR
Girls: 0 - 18 yrs
Grade I - 7%
Grade II - 22%
Grade III - 6 %
Grade IV - 1%
Grade V - < 1%
DMSA Scintigraphy
Intravenous injection of a
radiopharmaceutical labelled with TC-99m
DMSA is concentrated in the proximal renal
tubules. Identifies functioning renal tissue
Images obtained between 2-6 hours after
injection
Usually requires sedation in children < 3
years of age
Timing of DMSA
• Acute imaging: Within 5-7 days of acute
infection
• 90% sensitivity for pyelonephritis
• Cannot differentiate pyelonephritis from renal
scarring
• Delayed imaging ~ 6-12 months after
UTI
• Assess for renal damage
• Gold standard for detection of parenchymal
defects
DMSA
Normal
Renal Scarring
Risk of Renal Parenchymal Defects
In the presence of VUR, more frequent in
boys and children > 1 year of age
~ 5% of children presenting with 1st febrile
UTI will have parenchymal defects
Pyelonephritis and renal scarring occur as
frequently in children without VUR as with
VUR
In the general population: 0.5 - 0.13% girls
versus 0.17 - 0.11% boys will develop reflux
nephropathy
Renal Parenchymal Defects
Boys more susceptible to developing
dysplasia or parenchymal defects in utero
Girls tend to acquire their parenchymal
defects at a later age
Infants have a higher risk of renal damage
Recurrent UTI’s a significant risk factor for
girls, not boys
The only effective way to reduce renal
scarring associated with UTI’s is early
diagnosis and prompt, effective treatment
Renal Damage
Of children with acute pyelonephritis
diagnosed by DMSA, 38-57% will develop
permanent renal scarring
Seen in 78% of infants with dilating
reflux(grades III-V), obstruction, clinically
relevant anomalies (renal aplasia, ectopic
kidney, complete duplication)
Seen in 15% of infants without the above
diagnoses
Risk of Renal Scarring
Risk of Renal Scarring versus # of UTI’s
A 5 year old female has recurrent febrile
UTI’s. What imaging study would be useful to
detect renal scarring?
38%
38%
A.
B.
C.
D.
VCUG
US
CT abdomen
DMSA scan
13%
A.
B.
13%
C.
D.
Recommendations and
Guidelines
No universally accepted work-up for children
with UTI’s
Lack of consensus among different guidelines
Complex approaches; Regional variations
Multiple tables dividing children into different
age groups
Classifying UTI’s into different variants
Determine nature and timing of imaging
studies
Utility of Diagnostic Imaging Procedures
Identifying pathologic malformations and
risk factors
Changing management approaches
Affecting follow-up monitoring
Outside of Guidelines
Infants and children:
known pre-existent uropathy or underlying
renal disease
hydronephrosis or obstruction
neurogenic bladder
with urinary catheters in situ
immunosuppressed
Clinical Practice Guidelines
• Children’s Mercy Hospitals (last edited 2007)
• Included in Handout
• American Academy of Pediatrics (last edited 1999)
• Cincinnati Children’s (last edited 2006)
• NICE (National Institute for Health & Clinical
Excellence) (2007)
• Royal College of Physicians (1991)
CMH Guidelines
• Boys- All
• Girls < 36 months
• Girls 3-7 years of
age with fever >
38.5℃ ( 101.3 ℉)
Ultrasound
⇓
VCUG
⇓
If identification of
pyelonephritis or renal
scarring
⇓
DMSA
CMH Guidelines
• Girls > 3 years with
fever < 38.5℃ (101.3℉)
• All Girls > 7 years
Observation
without imaging
⇓
If subsequent UTI
⇓
Ultrasound
⇓
VCUG
⇓
If pyelonephritis or
renal scarring
⇓
DMSA
Children’s Mercy Guidelines
Children who should have RUS + VCUG
after 1st febrile UTI
Failure of good response after 48-72 hrs of
effective antibiotics
Infection with an unusual organism
Lack of assurance of close follow up
Abnormal urine stream, abdominal mass
Recurrence of febrile UTI
Timing of VCUG during Acute Illness
• VCUG during first 10 days of treatment IF
• The patient has good response to Tx;
afebrile > 24 hours
• The infecting bacteria is susceptible to
antibiotic administered
• Voiding pattern has normalized to preinfection
• Younger infant should have no dysuria and
normal behavior
An uncircumcized 2 month old male was admitted with a
febrile UTI that has not responded to antibiotic therapy
after 48 hours. When is the best time to perform a VCUG?
50%
A. On the day of
admission
B. After 24 hours
C. After 24 hours
without a fever
D. No need to do
VCUG
25%
13%
A.
13%
B.
C.
D.
Vesicoureteral Reflux
Classification per CMH Clinical Practice
Guidelines
Mild: grade I and II, unilateral grade III in a
child < 2 years old
Moderate-Severe: all other grade III’s, IV, V
Referral to Pediatric Urologist or
Nephrologist
Any child with evidence of urinary tract obstruction:
Refer to Pediatric Urologist
VUR > Grade III or evidence of renal damage
VUR > Grade III with break through infection
Any child with Grade V VUR should be referred
immediately.
The presence of Grade IV and lower grades of VUR
+ the presence of renal damage frequently reflects
intrauterine VUR and damage rather than acquired
damage.
Recommendations for
Follow-up VCUG’s
CMH Clinical Practice Guidelines:
In children maintained on prophylactic
Antibiotics:
every 2 years with grades I and II, and
for those < 2 years with unilateral grade
III
every 3 years for all others with grade III
and IV
Conclusions
• Better understanding of the impact of febrile
UTI’s on children
• Better understanding of some of the
radiologic procedures and findings
• Understanding of CMH Clinical Practice
Guidelines and ability to compare with other
Clinical Practice Guidelines from reputable
institutions
• Effects on diagnostic imaging and timing of
imaging procedures
AAP Guidelines
Every febrile infant or young child, 2
months-2 years of age, should be imaged
with ultrasound and a study to detect for
VUR
Those who do not demonstrate the
expected clinical response within 2 days
of antibiotics, should have ultrasound
promptly and reflux study at earliest
convenience
Cincinnati Children’s
Guidelines
Children with 1st UTI, need Ultrasound
and Voiding Cystogram:
all boys
girls age < 36 months (dependent on
ability to verbalize dysuria
girls 3-7 years with fever > 38.5 ℃
(101.3℉)
Observation without Imaging per
Cincinnati Children’s
Girls > 3 years with fever (< 38.5℃)
All girls > 7 years
Follow up with dipstick of routine
urinalysis if symptoms of UTI
NICE Guidelines
• Not recommend antibiotic prophylaxis
following 1st UTI, even in child with VUR
• Not routinely evaluate for VUR with
imaging
• Infants < 6 months with 1st UTI that
responds to treatment - US within 4-6
weeks of UTI
• Infants > 6 months- US not
recommended unless atypical UTI
NICE Guidelines
Infants
< 6 months
Responds to Tx
within 48 hours
Atypical UTI
Recurrent UTI
Ultrasound during
acute infection
No
Yes*
Yes
Ultrasound within
6 weeks
Yesª
No
No
DMSA within 4-6
months following
infection
No
Yes
Yes
VCUG
No
Yes
Yes
*In a child with non-E. coli UTI, responding well to antibiotics and no other
features of atypical infection, ultrasound can be requested on a non-urgent basis
ª If Ultrasound abnormal, consider VCUG
NICE Guidelines
Children
Responds well to Atypical UTI
6 months - < 3 yrs Tx within 48
hours
Recurrent UTI
Ultrasound during
infection
No
Yes*
No
Ultrasound within
6 weeks
No
No
Yes
DMSA 4-6 months
following acute
infection
No
Yes
Yes
VCUG
No
Noª
Noª
*In a child with non-E. coli UTI, responding well to antibiotics and no other features
of atypical infection, ultrasound can be requested on a non-urgent basis
ªConsider VCUG if dilatation on ultrasound, poor urine flow, non-E. coli infection,
family history of VUR
NICE Guidelines
Children > 3 yrs
Responds well to
Tx within 48 hours
Atypical UTI
Recurrent UTI
Ultrasound during
acute infection
No
Yes*
No
Ultrasound within 6
weeks
No
No
Yes
DMSA 4-6 months
following acute
infection
No
No
Yes
VCUG
No
No
No
*In a child with non-E. coli UTI, responding well to antibiotics and no other features
of atypical infection, ultrasound can be requested on a non-urgent basis
Royal College of Physicians in
1991
Infants: Ultrasound, VCUG, and DMSA
Children 1-7 yrs: Ultrasound and DMSA
> 7 yrs: Ultrasound and potential
additional exams dependent on
ultrasound findings
Guidelines of the Royal College of
Physicians
Ultrasound should be considered in all
cases of children with 1st UTI.
Late DMSA scintigraphy in children up to
7 years
VCUG in children < 1 year