The basics - UTIs in children

Recognising UTIs in children may be difficult because of non-specific signs and symptoms, says Dr Louise Newson.

Collecting urine and interpreting results are not easy in infants and children, but it is vital not to miss UTI.

There may be an underlying urinary tract anomaly that needs to be diagnosed, and infection may irreversibly damage the developing kidney. Failure to treat may also lead to sepsis.

During the course of childhood, 5 per cent of girls and 1.5 per cent of boys under the age of 11 years will have a UTI. At least 50 per cent of girls will suffer a second UTI during childhood, even in those with no urinary tract anomaly.

UTIs are usually due to bowel flora entering the urinary tract via the urethra.

Most UTIs (85 per cent) are due to Escherichia coli. Pseudomonas infection may suggest an underlying structural abnormality in the urinary tract.

Vesico-uteric reflux is a common underlying abnormality in UTI (SOVEREIGN, ISM / SCIENCE PHOTO LIBRARY)

Risk factors
Approximately 40 per cent of children suffering a UTI have an underlying urinary tract abnormality, most commonly vesico-ureteric reflux.

Renal scarring can be present in children at initial presentation and is a significant cause of hypertension and, occasionally, renal failure.

Other risk factors for UTI include impaired bladder emptying due to dysfunctional voiding or constipation, hurried micturition and obstructive lesions of the genitourinary system (eg urethral valves, anatomical abnormalities).

The likelihood of finding a significant urinary tract anomaly is far greater in a six-month-old boy with a febrile illness than a six-year-old girl with mild lower urinary tract symptoms.

Symptoms of a UTI in children, especially in babies, are often non-specific. The spectrum of illness extends from minor symptoms to life-threatening systemic illness.

Fever is an almost universal feature and is often accompanied by vomiting. Common presentations are listed in the box below.

Presentation of UTI in infancy and childhood
Infancy Childhood
FeverFever +/- rigors
IrritabilityDysuria and increased frequency
LethargyLethargy and anorexia
Failure to thrive/poor feedingVomiting and/or diarrhoea
Prolonged neonatal jaundiceAbdominal or loin pain
SepticaemiaOffensive urine
Febrile convulsion

Febrile convulsion

Diagnosis
It is important that a definite diagnosis is made with a urine culture and microscopy.

There is a risk of overdiagnosis and overtreatment of childhood UTIs. A third of suspected cases do not have the diagnosis confirmed by urine culture.

For those in nappies, urine can be collected using absorbent pads in the nappy; doing a 'clean-catch' when the nappy is off (easier in boys); using an adhesive bag on the perineum (problem with skin contaminants); suprapubic aspiration (severely ill) or MSU (older children).

If there is a family history of recurrent UTIs, the threshold for deciding to culture the urine should be lowered.

Urine dipsticks for urinary nitrites and leukocyte esterase can be useful. False negatives are few (<2 per cent) although false positives can occur (5-10 per cent). The urine culture should be repeated at least 24 hours after completing a course of antibiotics.

Atypical and recurrent UTIs
Those with either an atypical UTI or recurrent UTIs need to be identified, as their subsequent investigations are different to those with simple UTIs. The NICE guidelines clearly define atypical and recurrent UTI.1

Treatment
Antibiotics should be started as soon as possible when a UTI is suspected, after obtaining a specimen. Delay in starting treatment for repeated episodes of UTI is the main preventable risk factor for permanent renal damage.

NICE recommendations for treatment are shown in the box below.

A Cochrane Database systematic review suggests that treatment for two to four days seems to be as effective as treatment for 7-14 days for eradicating lower tract UTI in children.2

Investigations
Debate continues about optimal imaging strategies after first UTI.3 The NICE guidelines have produced some useful, but controversial, recommendations.1

For those six months and older with first-time UTI responding to treatment, routine ultrasound is not recommended.

Those with an atypical UTI should have an ultrasound during the acute infection to identify structural abnormalities.

Prevention of recurrence
Teaching good perineal hygiene is essential.

Dysfunctional elimination syndromes and constipation should be addressed.

Children should be encouraged to drink an adequate amount. They should not be expected to delay voiding.

They should be encouraged to try to void a second time a minute or two after micturition ('double voiding').

Antibiotic prophylaxis
NICE recommends that antibiotic prophylaxis should not be routinely recommended following first-time UTI.1

Antibiotic prophylaxis may be considered with recurrent UTIs but asymptomatic bacteriuria should not be treated with prophylactic antibiotics.

However, Clinical Knowledge Summaries suggest that children who suffer a second UTI within a year should receive short-term prophylactic antibiotics and be referred for their assessment for long-term use.4

NICE recommendations for treatment
The NICE guidance recommends that:
  • Infants younger than three months with a possible UTI should be referred immediately to the care of a paediatric specialist.
  • For infants and children three months or older with acute pyelonephritis or upper UTI:
    - consider referral to a paediatric specialist;
    - treat with oral antibiotics for 7-10 days. The use of an oral antibiotic with low resistance patterns is recommended, for example cephalosporin or co-amoxiclav;
    - if oral antibiotics cannot be used, treat with an IV antibiotic agent for two to four days followed by oral antibiotics for a total duration of 10 days.
  • For infants and children three months or older with cystitis or lower UTI:
    - treat with oral antibiotics for three days; choice of antibiotics should be directed by locally developed guidance.
  • Dr Newson is a GP in the West Midlands

References

1. NICE guideline CG54 Urinary tract infection in children. London: NICE, 2007.

2. Michael M, Hodson E M, Craig J C, Martin S, Moyer V A. Short versus standard duration oral antibiotic therapy for acute urinary tract infection in children. Cochrane Database Syst Rev 2003, Issue 1. Art No: CD003966. DOI: 10.1002/14651858.CD003966

3. Keren R. Imaging and treatment strategies for children after first urinary tract infection. Curr Opin Pediatr 2007; 19: 705-10.

4. Clinical Knowledge Summaries. Urinary tract infection - children .

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