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Urinary Tract Infections in Children

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Overview

Urinary tract infections (UTIs) are common in children, however, their presence may suggest the presence of a urinary tract abnormality. The signs and symptoms of UTIs can be non-specific, especially in neonates and infants. 

Definitions

  • Lower UTIs (cystitis) affect the bladder and urethra
  • Upper UTIs (pyelonephritis) affect the renal pelvis and kidneys
  • UTIs are atypical if any of the following apply:
    • Poor urine flow
    • Abdominal or bladder mass
    • Serious illness
    • Sepsis
    • Raised creatinine
    • Failure to respond to antibiotics within 48 hours
    • Infection with organisms that are not E. coli
  • UTIs are classified as recurrent if any of the following apply:
    • ≥2 episodes of upper UTI
    • 1 episode of upper UTI plus ≥1 episode of lower UTI
    • ≥3 episodes of lower UTI

Epidemiology

  • UTI with fever is the most common serious bacterial infection in childhood
  • 1 in 10 girls and 1 in 30 boys will have had a UTI by the age of 16 years

Causes

Overview

The most common causes are:

  • Escherichia coli (E. coli) – up to 90% of cases
  • Proteus mirabilis – around 30% of cases
  • Candida UTI can occur in people who are immunocompromised/immunosuppressed

Risk Factors

  • Age <1 year old
  • Female sex
  • Previous UTI
  • White children
  • Underlying abnormalities with the urinary tract
  • Constipation
  • Sexual activity including sexual abuse
  • Immunosuppression

Presentation

Overview

Presentation varies depending on age:

  • <3 months old:
  • Young children >3 months:
    • Fever, abdominal pain, loin tenderness, vomiting, dysuria, urinary frequency, poor feeding, incontinence
  • Older children present similarly to adults with dysuria, urinary frequency, and haematuria

Pyelonephritis should be suspected in all children if any of the following apply:

  • Fever ≥38°C
  • Loin pain/tenderness

Investigations

Overview

Since infants and children may present with upper or lower UTIs with vague symptoms, NICE recommends testing the urine of a child in the following scenarios:

  • Signs or symptoms suggesting the presence of a UTI
  • Unexplained fever ≥38°C (within 24 hours) 
  • The child has an alternate site of infection but is still unwell (within 24 hours)

NICE has also produced guidelines regarding urine collection:

  • A clean catch urine sample is ideal
  • Cotton wool balls, gauze, or sanitary towels should not be used
  • Catheter samples or suprapubic aspiration should be performed if it is not possible or practical to collect urine by non-invasive methods

Management

Overview

  • Infants <3 months: immediately refer to a paediatrician and admit to hospital
    • They require IV antibiotics, blood cultures, lactate, and possibly a lumbar puncture as infants <3 months with UTI may have sepsis, and some may also have bacterial meningitis
  • >3 months and upper UTI: consider hospital admission
    • If hospital admission is not arranged, first-line options are oral cefalexin or co-amoxiclav for 7-10 days
  • >3 months and lower UTI: 3-day course of oral antibiotics
    • The usual antibiotics used include trimethoprim, nitrofurantoin, amoxicillin, or cefalexin

Children ≥3 months old with recurrent UTIs should be referred to a paediatrician for further investigations.

Recurrent Urinary Tract Infections

Overview

Investigating recurrent UTIs involves the use of ultrasound scans, dimercaptosuccinic acid (DMSA) scans, and micturating cystourethrograms. NICE has set out guidelines on which patients should have what investigation.

Ultrasound scans

Offer an ultrasound scan if any of the following apply:

  • All babies <6 months with their first UTI:
    • If the UTI responds well to treatment within 48 hours, this is within 6 weeks
    • If the UTI is atypical or recurrent, this is done during the infection
  • Children with recurrent UTIs within 6 weeks
  • Children with atypical UTIs during the infection

Dimercaptosuccinic acid (DMSA) scan

Offer a dimercaptosuccinic acid (DMSA) scan within 4-6 months to assess for renal tract damage if any of the following apply:

  • Babies at any age up to 3 years with any of the following:
    • An atypical UTI
    • Recurrent UTIs
  • Children aged 3 years or older with recurrent UTIs

Micturating cystourethrogram (MCUG)

Offer a micturating cystourethrogram (MCUG) if any of the following apply:

  • Babies <6 months with any of the following:
    • Atypical UTI
    • Recurrent UTIs

Patient Advice

  • Parents/carers should bring the child back for reassessment if they are still unwell after 24-48 hours of treatment.
  • Children should have adequate fluid intake to avoid dehydration
  • Children may be given paracetamol for pain relief

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