Urinary tract infection (UTI) in children4% of boys and 12% of girls will have had a UTI by the age of 16 years: of these 4% will get kidney scars and 50% may develop hypertension at some point in their life and 10% of those scarred will develop renal failure at some point in their lives.
Symptoms include
- Dysuria, frequency, haematuria, smelly urine
- Bed wetting (new/recurrence)
- Abdominal pain/discomfort Pyrexia of unknown origin
- General malaise/non specific illness
- Failure to thrive
- Not feeding well
- Vomiting
- Prolonged jaundice in the new born
- or none of these
Scarring occurs in children who have vesico-ureteric reflux and urinary tract infection. Scars can happen within three days. If children have not scarred their kidneys by the age of four, there is good evidence that they will not scar after that age (1997) .
A child may have scarred its kidney many years prior to a first recognised UTI. A child may have scarred its kidney many years prior to a first recognised UTI (they may have had a "silent" undetected UTI).
Summed up ......
- No reflux, no scar
- No UTI, no scar
- Reflux + UTI may produce focal scars
Therefore, when presented with a child (of any age) with an illness of uncertain cause always collect a urine sample.
Collecting urine
- In babies:
- Newcastle urine collection pads
- In older children:
- Midstream or clean catch or
- in toddlers a washed up (with washing-up liquid) potty can be used (or a foil pot placed in the potty)
Management
- Microscopy not available
- Collect urine and send for C&S, start antibiotics straight away (NO DELAY)
- If confirmed continue treatment and refer
- If negative on C&S - STOP treatment (NOT UTI)
- Microscopy available
- Collect urine and microscope
- If negative on microscopy - NOT UTI
- If positive on microscopy - start antibiotics and send for culture and sensitivities to confirm diagnosis
- When confirmed refer.
How can UTIs be diagnosed in children?
- CULTURE (urine collected and stored in fridge if necessary over weekend) including dipslides Microscopy followed by culture
- Appearance cloudy/smelly - unreliable
- Stix for nitrites/leucocytes - unreliable in children, however may show something else i.e. proteinuria, haematuria or indicate glomerulonephritis
Treatment
- If clinical suspicion antibiotics treat with best guess antibiotic (Trimethoprim or Cephalexin)
- Change antibiotic if necessary following culture and sensitivity result
- Place on prophylaxis all children under 4 years of age and any children with recurrent UTIs until investigations are performed
- Refer all children after 1st proven UTI for investigations
Investigations
- All children have an abdominal ultrasound:
structural information; shows dilatation, obstruction,
cysts, stones, bladder etc.
- Gross abnormalities only, little information about small scars
- (It is non-invasive, safe, pleasant and cheap)
- All children have a DMSA scan (TC00
dimercaptosuccinic acid)
- This is a protein bound radio isotope which is taken up by the proximal tubules. It involves a small injection (Emla used) 1-2 hours before scan
- Very little co-operation is needed
- Static and shows up parenchyma (i.e. "meat" of the kidneys)
- MCUG (micturating cystogram urethral/supra pubic catheterisation) It is the only way of demonstrating vesico-ureteric reflux This is an additional investigation done in : the very young (<1 year) or those children with a family history of reflux or if abnormal DMSA or ultrasound. IVU seldom done unless specific information required (usually anatomical information). This is because it is poor at showing small scars and radiation dose is higher than radio-isotope studies)
Subsequent management
Under 1 year of age:
- If normal MCUG, U/S and DMSA:
- Discharge
- If abnormal MCUG, U/S or DMSA:
- structural: surgical opinion
- scarring - if refluxing still, continue prophylaxis and urine monitoring every 3 months and when child unwell
- always monitor BP for life
- Reflux alone:
- prophylaxis (trimethoprim) is given
- urine monitored every three months and when child unwell
- re-investigate at 4 years of age
1-4 years of age
- If U/S and DMSA normal:
- monitor for UTIs until 4 years of age (specimen of urine checked every 3 months and when child unwell
- If DMSU shows scarred kidneys:
- MCUG performed
- monitor urine (every 3 months) and keep on prophylaxis
- if refluxing when MCUG performed, continue prophylaxis (trimethoprim) and urine monitoring
- monitor BP for life
- If further UTI under 4 years:
- MCUG and repeat DMSA (however in practice between the ages of 3.5 and 4 years usually just the DMSA is repeatd and then a MCUG only if DMSA abnormal
- if no more UTIs by 4 years - discharge
Over 4 years of age (up to 16yrs)
- If U/S and DMSA results normal
- discharge
- If abnormal DMSA (scarred kidneys)
- MCUG: if still refluxing prophylaxis (trimethoprim) and urine monitoring
- monitor BP for life
- A child over 4 years of age with recurrent UTIs and normal investigations is not considered to be at risk of scarring
- For problematic, repeated UTIs
- refer
KEY MESSAGE
ALWAYS CHECK A URINE IN SICK INFANTS
In suspected UTI, always collect a urine sample (if necessary store in fridge overnight) before starting treatment and send for culture and sensitivity. Refer ALL children after a first documented UTI whatever their age!
Source: Sue Vernon, Paediatric Nurse Practitioner, RVI.
A protocol
Introduction
Childhood UTIs are important. They can lead to considerable morbidity and may be the marker of significant congenital abnormality. If associated with vesico-ureteric reflux, they can precipitate renal scarring, hypertension and chronic renal failure. Scarring can occur in the susceptible kidney after only three days of infection. The risk is highest in children less than two years old, in those with a family history of renal abnormality, with macroscopic haematuria or upper renal tract symptoms.
Primary care
Children will generally present to members of the primary health care team. Often they complain of “cystitis” like symptoms; rarely they present with acute pyelonephritis or even acute renal failure. The younger the child, the less specific the symptoms may be, and children can be entirely asymptomatic. A high index of suspicion is therefore required.
Frequency and dysuria is only due to UTI in about 25% of cases. Other conditions which may mimic UTI include
- vulvitis/balanitis due to poor hygiene or skin infection, esp. candida
- pin worms
- constipation
- other viral infections.
Clinical examination should include height/weight, palpation of the abdomen for renal masses and faecal loading, percussion of the bladder and BP (paediatric cuff of correct size, which is the largest that will fit).
Urine collection in babies is best done with collection pads. Toddlers may wee in a washed-out potty (fairy liquid and hot water), or an opportunistic parent may succeed in the clean catch. Older children will co-operate with producing a mid-stream urine.
The Newcastle Paediatric Nephrology Team recommend microscopy (phase-contrast; looking for bacteria) as the most reliable way of making a diagnosis of UTI. Primary care teams which don’t have that facility may wish to use other techniques to aid in the initial diagnosis. It is important to be aware of the pitfalls of side-room tests:
- Leukocyte esterase stix will show the presence of leukocytes, which is not automatically synonymous with UTI (and vice versa)
- Nitrate strips are highly specific, but if negative tell you nothing, and may only become positive after many hours.
All children should have a urine culture sent off. There are issues around transport in rural areas. Urine should be stored at 4oC; over a weekend is not ideal but acceptable. If in doubt, start treatment. Any child under the age of four should remain on prophylaxis until investigations have been completed.
Treatment should be for five days with one of the following:
- Trimethoprim 8mg/kg/day (prophylaxis 2mg/kg/day)
- Nitrofurantoin 3mg/kg/day (prophylaxis 1mg/kg/day)
- Cephalexin 25mg/kg/day (prophylaxis 125mg daily)
Every child should be investigated following their first proven UTI. The decision about whether the UTI is “proven” or not rests with the child’s GP, who needs to reach a diagnosis based on clinical, laboratory and microbiology findings.
Children under the age of one: these should be referred straight to the paediatric nephrology department at the RVI for micturating cysto-urethrogram.
Children over the age of one: advise the parents that their child will need to undergo abdominal ultrasound and DMSA scanning.
Generally the results are reassuringly normal. Children under four can then stop prophylaxis, but urine monitoring should continue three monthly until they have attained their fourth birthday.
All other children can just have future UTIs treated in the conventional manner.