Urinary tract infection (UTI)

N39.0

DESCRIPTION

Bacterial infection of the urinary tract.

Uncomplicated urinary tract infection (UTI) is an infection, which is limited to the lower urinary tract, and there are no associated urological anomalies. It is seen most commonly in girls over two years of age.

Complicated urinary tract infection (UTI) is an infection of the urinary tract involving the renal parenchyma (acute pyelonephritis) or which is associated with underlying congenital anomalies of the kidneys and urinary tract. It may result in significant short-term morbidity, including septicaemic shock and acute renal failure, especially in infants. Permanent renal damage may occur in children who have recurring episodes of pyelonephritis.

DIAGNOSTIC CRITERIA

Clinical

  • Signs and symptoms are related to the age of the child and are often non-specific. Uncomplicated urinary tract infections present with localising symptoms of dysuria, frequency, urgency, cloudy urine and lower abdominal discomfort. Urine test strip shows positive leucocyte esterase, nitrites and haematuria.
  • Complicated infections may present with fever and other systemic features described below:
  • Neonates may present with:
    • fever,
    • vomiting,
    • hypothermia,
    • prolonged jaundice,
    • poor feeding,
    • failure to thrive,
    • sepsis,
    • renal failure.
  • Infants and children may present with:
    • failure to thrive,
    • frequency,
    • persisting fever,
    • dysuria,
    • abdominal pain,
    • enuresis or urgency.

A urinary tract infection must be excluded in any child with fever of unknown origin.

Special investigations

  • Urine bag specimens are used for screening purposes only.
    • When urine dipstick test of bag specimen reveals presence of leucocytes or nitrites, collect urine aseptically for urine MCS.
    • Urine specimen is collected aseptically:
      • by in/out catheter or suprapubic aspiration in acutely ill children < 2 years of age or in smaller children who are unable to co-operate or
      • by mid-stream clean catch method in older children.
  • Criteria for the diagnosis of UTI:
    • any culture from a suprapubic urine sample,
    • a culture of > 10⁴ col/mL urine of a single organism from a catheter specimen,
    • a pure culture of > 10⁵ col/mL in a mid-stream clean catch sample or consistent culture of a pure growth even with counts as low as 10⁴ /mL.
  • Ultrasound:
    • Do a renal ultrasound in all children with first UTI as soon as possible, unless a normal ultrasound was previously seen.
  • MCUG:
    • in children who have abnormalities of the kidneys, ureter or bladder demonstrated by ultrasound.

GENERAL AND SUPPORTIVE MEASURES

  • Ensure adequate nutrition and hydration. Maintain hydration with oral and/or IV fluids if necessary.
  • For recurring infections:
    • avoid irritant soaps and bubble baths,
    • treat constipation, if present,
    • treat pinworm,
    • perineal hygiene,
    • regular complete emptying of the bladder and/or double voiding, i.e. making an additional attempt at voiding after the initial flow of urine has ceased.

NOTE: Consider the possibility of sexual abuse in children presenting with a UTI with genital, perineal and/or anal bruising, abrasions or lacerations; secondary incontinence or a marked fear of examination.

MEDICINE TREATMENT

Uncomplicated UTI

See the PHC STGs and EML, Section Standard Treatment Guidelines and Essential Medicines List for Primary Health Care Level. NB: antibiotic therapy for 3 days only

LoEI [1]

Complicated UTI

Antibiotic therapy

Total duration of antibiotic therapy: 7 days.

IMPORTANT:

Increase duration to 10–14 days in infants who have

acute pyelonephritis or septicaemia.

LoEI [2]

The empiric choice of antibiotics depends on the expected sensitivity of the suspected organism. Review antibiotic choice once culture and sensitivity results become available.

Oral treatment:

Children > 3 months old, who are unwell but not acutely ill and who are not vomiting:
Children with uncomplicated UTI:

  • Amoxicillin/clavulanic acid, oral, 25 mg/kg/dose of amoxicillin component 8 hourly.

Parenteral treatment:

All neonates and acutely ill infants should preferably be treated parenterally for the first few days until temperature has normalised and they are able to tolerate feeds.

  • Amoxicillin/clavulanic acid, IV, 25 mg/kg/dose 8 hourly.
    OR
  • Ceftriaxone, IV, 80 mg/kg daily.

If there is no improvement after 24 hours of IV amoxicillin/clavulanic acid treatment, a resistant organism may be the cause, and treatment should be according to culture. Consult a specialist.

If there is evidence of good clinical response to amoxicillin/clavulanic acid alone, change to:

  • Amoxicillin/clavulanic acid, oral, 25 mg/kg/dose of amoxicillin component 8 hourly.

Penicillin Allergy

See Chapter: Drug Allergies, Allergies to Penicillin .

For pain:

  • Paracetamol, oral, 15 mg/kg/dose, 6 hourly as required.

For children with a structural or functional abnormality of the urinary tract:

Investigate for recurrent UTIs if the patient has temperature > 38.5˚C or symptoms of urinary tract infection by performing a urine dipstick test.

If positive leucocytes and/or nitrites in are present in fresh urine, collect urine aseptically for MCS and treat empirically as above for urinary tract infection.

Prophylactic Antibiotic Therapy:

Prophylaxis may be indicated in specific risk groups, i.e. for children < 2 years of age and who have a structural or functional abnormality of the urinary tract associated with increased risk of recurrent infections, i.e. grade III or more vesico-ureteric reflux. In this setting consult nephrologist and microbiologist.

Asymptomatic bacteriuria does not require treatment.

Use of long-term prophylactic antibiotic therapy for UTI is not recommended.

REFERRAL

  • Poor response to adequate therapy, i.e. persistent positive urine culture and/or fever.
  • If complicated urinary tract infection, i.e. obstruction is suspected or renal failure present.
  • If recurrent urinary tract infections or repeated positive pure culture of any micro-organism.