UTI

Question 1

In whom is UTI more common, boys or girls?

Answer 1

• More common in boys until 3 months of age (due to more congenital abnormalities), after which the incidence is substantially higher in girls.

Question 2

Aetiology of UTI

Answer 2

• Infection
• Vesico-ureteric reflex (VUR): minor not on US -major can be seen on US, hydronephrosis
• Congenital abnormality
• Posterior urethral valves - usually in-utero Dx, hydronephrosis seen

Question 3

What might a UTI present as?

Answer 3

• Infants often non-specific: e.g. fever, irritability, poor feeding and vomiting
• Children: abdominal/loin pain, frequency, dysuria, haematuria

Question 4

What investigations might you do if you were screening for a UTI vs. suspicious of one?

Answer 4

• Screening test only: full ward test (FWT i.e. urine dipstick), particularly poor in <3yo
• If suspect UTI: + microscopy + culture (esp < 3yo)
  
  • Blood culture and LP considered if child <4weeks

Question 5

Describe the different methods of obtaining a urine sample and when each is indicated.

Answer 5

If child can void on request:

1. MSU
   
   • > 10^8 growth = infection, >10^5 = early infection, needs repeat collection

If child can’t void on request:

1. Clean catch (preferred)
2. SPA
   
   • If child old enough, only use if non-invasive methods are not successful
   • Send for culture
3. Catheter specimens
   
   • Only if SPA failed
   • Send for culture: >10^3 growth indicates infection

Question 6

How might you collect a clean catch?

Answer 6

Clean genitalia with just water and either:

1. Try catch mid stream urine with container
2. Leave small clean dish between exposed legs (e.g. new aluminium pie dish - doesn’t need to be sterilised)

Question 7

What typical urine markers seen in adult UTI are unrealiable in paediatrics?

Answer 7

blood, protein, nitrites (take time to develop/not all organisms), leukocyte esterase (can only be detected with high WBC), leukocytes (can appear in other illlnesses)

Question 8

At what age is a child always admitted for a UTI, and why?

Answer 8

Usually <6 months admitted, because risk that its more than just a UTI, and is pyelonephritis

Question 9

What is the Mx of a UTI?

Answer 9

• IV: any child who is unwell, and most children < 6 months
  ○ gentamicin (G-ve) and benzylpenicillin(enterococcus)
• Oral Abx: 10 days total if < 2 years, 7 days if older:
  • Trimethoprim 4mg/kg (max 150mg) BD
  • TMP/SMX (8mg-40mg per mL, 0.5mL/kg) BD
  - Co-trimoxazole, bactrim
  • Cephalexin 15mg/kg (500mg max) TDS

Question 10

What must you remember about using aminoglycosides?

Answer 10

Levels pre-3rd dose

Question 11

When do we use prophylaxis in UTI with children?

Answer 11

• Routine prophylaxisis no longer recommended

Question 12

When do we do follow-up renal US after a UTI?

Answer 12

• Children with atypical UTI, those not responding to treatment within 48 hours, and boys < 3 months of age should have a renal tract ultrasound to exclude renal obstruction
• Children < 6 months should have a renal US within 6 weeks of diagnosis
• Older children may require renal US for recurrent UTI