Urinary Tract Infection ✅ Flashcards
What is the most common bacterial infection in childhood?
UTI
Which gender are UTIs more common in?
Girls (except in early infancy, when boys get more)
What % of girls will experience a UTI by 10 years old?
8%
What % of boys will experience a UTI by 10 years old?
1%
What is diagnosis of UTI based on?
Urine microbiology
What type of urine sample is usually the best for urine microscopy?
Clean catch midstream sample
What other method of urine collection does NICE advocate for?
Absorbent urine collection pads
What urine collection method does NICE not recommend the use of?
Adhesive plastic bags
What urine sample collection method can be used in certain circumstances?
Catheter sample or suprapubic aspiration
When might catheter sample urine or suprapubic aspiration be used to obtain a sample in UTI?
In severely ill infants under 1 year of age, where an urgent diagnosis and early start of antibiotics is indicated
What does the bacterial growth rate that is considered to be significant on urine samples depend on?
The mode of collection
What bacterial growth rate is significant with a clean catch urine sample?
100,000 CFU/ml
What bacterial growth rate is significant with a catheter urine sample?
50,000 CFU/ml
What bacterial growth rate is significant with a suprapubic aspiration urine sample?
Any growth
How useful is urinary WBC?
Presence or absence alone is not reliable
What other conditions may cause a raised urinary WBC?
- Febrile children
- Balanitis
- Vulvovaginitis
What can cause a false raise in urinary WBCs?
Lysis during storage
What is suggestive of UTI on urine dip?
Positive for leukocyte esterase and nitrates
What is the most common organism causing community acquired UTI?
E. coli
What % of childhood UTIs are E. coli?
75%
What are the other important organisms causing UTIs?
- Enterococci
- Klebsiella
- Proteus
- Serratia
What is the most important contributing factor to the development of UTIs?
Urinary stasis
What can cause urinary stasis?
- Anatomical obstruction
- Vesico-ureteric reflux
- Incomplete or inefficient voiding habits
- Low fluid intake
- Constipation
What other factors are important in the development of UTIs?
- Periurethral colonisation
- Impaired host defence
Give an example of when you might get periurethral colonisation?
In phimosis
What should empirical treatment with antibiotics be based on?
Local knowledge of prevalent strains and their sensitivities
What should be done if there is no response to empirical antibiotics within 24-48 hours?
A review of culture report and change in antibiotic should be considered
What investigations might be used in UTI?
- Abdominal USS
- DMSA scan
- MCUG
When is an abdominal USS done in UTI?
- Under 6 months with typical UTI
- Atypical or recurrent UTIs
What is considered an atypical UTI?
- Seriously ill
- Poor urine flow
- Abdominal or bladder mass
- Sepsis
- Raised creatinine
- Failure to respond to suitable antibiotics within 48 hours
- Infection with non-E.Coli organisms
What is considered to be a recurrent UTI?
- 2 or more episodes of UTI with acute pyelonephritis/upper urinary tract infection
- 1 episode of UTI with acute pyelonephritis/upper urinary tract infection, plus 1+ episode of UTI with cystitis/lower urinary tract infection
- 3+ episodes of UTI with cystitis/lower urinary tract infection
What is the advantage of USS in investigating UTIs?
- Non-invasive
- No radiation risk
- Can identify serious structural abnormalities, as well as urinary obstruction
Give 2 examples of serious abnormalities hat can be identified on USS?
- Posterior urethral valve
- Pelvi-ureteric junction obstruction
What might abdominal USS miss in UTI?
Renal scars
What is the gold standard investigation for identifying renal scars?
DMSA scan
When should DMSA scans be done?
4-6 months after acute UTI
Why should DMSA scans be delayed until 4-6 months after the UTI?
To avoid false positive results secondary to acute renal parenchyma inflammation in pyleonephritis
What might DMSA scans miss?
Significant vesico-ureteric reflux (VUR)
What is the gold standard investigation for identification of significant VUR?
MCUG
What simple measures can be taken to prevent recurrence of UTIs?
- Adequate fluid intake
- Avoiding constipation
- Proper toilet hygiene
Should routine antibiotic prophylaxis be used in the prevention of UTIs?
No
When should routine antibiotic prophylaxis be considered for UTIs?
- Recurrent UTI
- Significant VUR (grade 3+)
What antibiotic is most often used for UTI prophylaxis?
Trimethoprim
What antibiotics should be avoided for UTI prophylaxis?
Broad spectrum antibiotics such as amoxicillin
Is repeat urine culture to check resolution advised in UTI?
No
Which children with UTIs do not require follow up?
Those that do not qualify for routine investigation
When should antibiotic prophylaxis be stopped in UTIs?
No evidence, but generally considered once the child becomes toilet trained
What is required for any child with renal scarring?
Lifelong BP management
In what % of children with renal scarring is hypertension reported in?
10%
What do bilateral renal scarring increase the risk of?
CKD
What is required when a child has bilateral renal scars?
Regular reviews for hypertension, proteinuria, and renal dysfunction
What might be of benefit in boys with recurrent UTIs?
Circumcision
What is the number needed to treat for circumcision to prevent UTIs in normal children?
100
When is the number needed to treat lower for circumcision to be of benefit in UTIs?
- Recurrent UTIs (11)
- High grade VUR (4)
When should surgical correction of VUR be considered?
Recurrent UTIs and progression of renal scars
What is the limitation of surgical correction of VUR?
Outcome has not been shown to be better than antibiotic prophylaxis alone
