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Urinary Tract Infections in

Children

Diagnostic Imaging based on Clinical

Practice Guidelines

Emily D. Kucera, M.D.

Assistant Professor, UMKC

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LearningObjectives

State prevalence, associations, andconsequences of febrile UTIs 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 CMHguidelines and include others in handout.

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Febrile UTIs

Most common serious bacterial infectionoccurring in infancy and childhood

Affects at least 3.6% of boys, 11% of girls

10-30% of children with febrile UTIs willdevelop renal scarring

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Diagnosis of UTI

Combination of clinical features andpresence of bacteria in urine > 10cfu/ml

Acute pyelonephritis = UTI + fever

> 38(100.4) - most common ininfants

Cystitis = symptoms of dysuria, frequency,

suprapubic pain in toilet-trained child

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Urinary Tract Infections in

Children

Prevalence of positive culture in children 0-21years 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 UTIs are found

to have acute pyelonephritis

All infants < 8 weeks of age with fever should be

suspected of having an upper tractinfection/pyelonephritis

O i A i d i h

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Organisms Associated with

UTIs in Children

Escherichia coli- Most common organism; causative agent in > 80% of 1st UTI

Klebsiellaspecies - 2nd most common organism. Seen more in young infants

Proteusspecies - May be more common in males

Enterobacterspecies - cause < 2% of UTIs

Pseudomonasspecies - cause < 2% or UTIs

Enterococcispecies- Uncommon > 30 days of age

Coagulase-negative staphylococcus- Uncommon in childhood

Staphylococcus aureus- Uncommon > 30 days of age

Group B streptococci- Uncommon in childhood

_

+

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Risk Factors for UTIs

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)

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Atypical UTIs

Seriously ill

Poor urine flow

Abdominal or bladder mass

Raised creatinine Septicemia

Failure to respond to treatment within

48 hrs Infection with non- E. coliorganisms

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Seriously Ill

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Recurrent UTIs 2 or more episodes of acute

pyelonephritis / upper urinary tractinfection

or

1 episode of acute pyelonephritis + > 1episode of cystitis

or

> 3 episodes of cystitis/lower urinarytract infection

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Recurrent UTIsGirls are more prone to recurrences with

ageChildren who present early in life with UTI

are more prone to recurrences

of children presenting < 1 year will haverecurrences

> 1 year of age ~ 40% of girls, 30% of boys

Overall incidence of UTI recurrences afterpyelonephritis is 20.1%

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Asymptomatic Bacteriuria

Most common in boys in early infancy1.6% 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

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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 UTIs and slower resolution ofreflux

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Associations with UTIs

Dysfunctional Elimination Syndromes(DES)

67% of girls with DES develop UTIs

40% of girls with UTIs have DES20% of girls with DES have reflux

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A 6 month old female has had 3UTIs Which of the following is the

best approach?

A. B. C. D.

63%

0%

13%

25%

A. No imaging

neededB. US + VCUG

C. MRI

D. DMSA scan

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Imaging Procedures

Ultrasound - detect renal anomalies, dilatation,

renal sizes, bladder abnormalities, ureteraldilatation

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

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norma rasounFindings

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

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NormalHydronephrotic MCDK

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1 2

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1 2

43

Duplicated Collecting

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Duplicated CollectingSystems

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, orobstruction

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Duplicated Collecting Systems

Non-dilated Dilated

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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

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Need for Sedation Sedation not needed in the vast majority of the

cases CMH Guidelines for sedation follow the AAP

andASA (Anesthesia) Guidelines

If need for anxiolysis, please directlycommunicate 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.

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Vesicoureteral Reflux

International Reflux Grading System ofVUR

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V i t l R fl

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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%

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Prevalence of VUR

Girls: 0 - 18 yrsGrade I - 7%

Grade II - 22%

Grade III - 6 %Grade IV - 1%

Grade V - < 1%

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DMSA Scintigraphy

Intravenous injection of aradiopharmaceutical 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

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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

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DMSA

Normal Renal Scarring

Ri k f R l P h l D f t

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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 asfrequently in children without VUR as with

VUR

In the generalpopulation: 0.5 - 0.13% girlsversus 0.17 - 0.11% boys will develop reflux

nephropathy

Renal Parenchymal Defects

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Renal Parenchymal DefectsBoys more susceptible to developing

dysplasia or parenchymal defects in uteroGirls tend to acquire their parenchymal

defects at a later age

Infants have a higher risk of renal damageRecurrent UTIs a significant risk factor for

girls, not boys

The only effective way to reduce renalscarring associated with UTIs is early

diagnosis and prompt, effective treatment

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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 abovediagnoses

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Risk of Renal ScarringRisk of Renal Scarring versus # of UTIs

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A 5 year old female has recurrent febrile

UTIs. What imaging study would be useful to

detect renal scarring?

A. B. C. D.

38% 38%

13%13%

A. VCUGB. US

C. CT abdomen

D. DMSA scan

Recommendations and

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Recommendations and

Guidelines

No universally accepted work-up for childrenwith UTIs

Lack of consensus among different guidelines

Complex approaches; Regional variations

Multiple tables dividing children into different

age groups

Classifying UTIs into different variants

Determine nature and timing of imagingstudies

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Utility of Diagnostic Imaging Procedures

Identifying pathologic malformations andrisk factors

Changing management approaches

Affecting follow-up monitoring

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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

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Clinical Practice Guidelines

Childrens Mercy Hospitals (last edited 2007)

Included in Handout

American Academy of Pediatrics(last edited 1999)

Cincinnati Childrens (last edited 2006)

NICE (National Institute for Health & Clinical

Excellence) (2007)

Royal College of Physicians (1991)

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CMH Guidelines

Boys- All

Girls < 36 months

Girls 3-7 years of

age with fever >

38.5( 101.3 )

Ultrasound

VCUG

If identification ofpyelonephritis or renal

scarring

DMSA

CMH G id li

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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

Child M G id li

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Childrens Mercy Guidelines

Children who should have RUS + VCUGafter 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

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An uncircumcized 2 month old male was admitted with afebrile UTI that has not responded to antibiotic therapy

after 48 hours When is the best time to perform a VCUG?

A. B. C. D.

13%

25%

50%

13%

A. On the day of

admissionB. After 24 hours

C. After 24 hours

without a feverD. No need to do

VCUG

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Vesicoureteral Reflux

Classification per CMH Clinical PracticeGuidelines

Mild: grade I and II, unilateral grade III in a

child < 2 years old

Moderate-Severe: all other grade IIIs, IV, V

Referral to Pediatric Urologist or

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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

intrauterineVUR and damage rather than acquired

damage.

Recommendations for

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Recommendations forFollow-up VCUGs

CMH Clinical Practice Guidelines:In children maintained on prophylactic

Antibiotics:

every 2years with grades I and II, andfor those < 2 years with unilateral grade

III

every 3years for all others with grade IIIand IV

Conclusions

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Conclusions Better understanding of the impact of febrile

UTIs on children Better understanding of some of the

radiologic procedures and findings

Understanding of CMH Clinical PracticeGuidelines and ability to compare with other

Clinical Practice Guidelines from reputable

institutions

Effects on diagnostic imaging and timing of

imaging procedures

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AAP Guidelines

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AAP GuidelinesEvery febrile infant or young child, 2

months-2 years of age, should be imagedwith ultrasound and a study to detect for

VUR

Those who do not demonstrate theexpected clinical response within 2 days

of antibiotics, should have ultrasound

promptly and reflux study at earliest

convenience

Cincinnati Childrens

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Cincinnati Children s

Guidelines

Children with 1st UTI, need Ultrasoundand Voiding Cystogram:

all boys

girls age < 36 months (dependent onability to verbalize dysuria

girls 3-7 years with fever > 38.5

(101.3)

Observation without Imaging per

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Observation without Imaging per

Cincinnati Childrens

Girls > 3 years with fever (< 38.5)

All girls > 7 years

Follow up with dipstick of routine

urinalysis if symptoms of UTI

NICE G id li

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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 thatresponds to treatment - US within 4-6

weeks of UTI

Infants > 6 months- US notrecommended unless atypical UTI

NICE G id li

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NICE GuidelinesInfants

< 6 months

Responds to Tx

within 48 hours

Atypical UTI Recurrent UTI

Ultrasound during

acute infection

No Yes* Yes

Ultrasound within

6 weeks

Yes No No

DMSA within 4-6

months following

infection

No Yes Yes

VCUG No Yes Yes

If Ultrasound abnormal, consider VCUG

*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

NICE Guidelines

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NICE GuidelinesChildren

6 months - < 3 yrs

Responds well to

Tx within 48

hours

Atypical UTI Recurrent UTI

Ultrasound during

infection

No Yes* No

Ultrasound within

6 weeks

No No Yes

DMSA 4-6 monthsfollowing acute

infection

No Yes Yes

VCUG No No No

Consider VCUG if dilatation on ultrasound, poor urine flow, non-E. coli infection,

family history of VUR

*In a child with non-E. coli UTI, responding well to antibiotics and no other featuresof atypical infection, ultrasound can be requested on a non-urgent basis

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Royal College of Physicians in

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Royal College of Physicians in1991

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

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Guidelines of the Royal College of

Physicians

Ultrasound should be considered in allcases of children with 1st UTI.

Late DMSA scintigraphy in children up to

7 yearsVCUG in children < 1 year