• Infants and children with unexplained fever of 38°C or higher should have a urine sample tested within 24 hours.
• Infants and children with an alternative site of infection should not routinely have a urine sample tested. If they remain unwell beyond 24 hours of initiating treatment/management, urine testing should be considered.

*Offensive urine may be also be due to dehydration or co-existing constipation.

Assess:The level of illness (Green - low risk, Amber - intermediate risk, Red - High Risk) in infants and young children in accordance with NICE guideline on Fever in Under 5s.

* Urgent referral to paediatrics, on-call registrar, via 01463 704000 (Raigmore Hospital switchboard)

BOX 1: Average systolic blood pressures by age (rough guide)

Reference: The Hands-on Guide to Practical Paediatrics, First Edition. Rebecca Hewitson and Caroline Fertleman. © 2014 John Wiley & Sons, Ltd. and APLS 6e

Definitions of UTI (BOX 2)

• Uncomplicated UTI (a terminology used sometimes): UTI in patients who have a normal, unobstructed genitourinary tract, no history of recent instrumentation and symptoms are confined to the lower urinary tract.

Urine collection - core principles.

• A clean catch urine sample is the recommended method for urine collection in infants and young children (non-toilet trained) and a mid-stream urine in an older child. Cleaning genitalia with water, prior to urine collection, is required.
• In infants, there is some evidence for the “Quick-Wee method” (fig. 1) for clean catch urine collection. It involves gentle, suprapubic, cutaneous stimulation using a gauze soaked in cold fluid for 5 minutes, which might significantly hasten bladder voiding in infants 1 to 12 months of age. Needless to say, before doing this, it is essential to be ready with a sterile bowl to catch the voided urine!
• Fig. 1 Quick-Wee method: 

• If a clean catch urine sample is unobtainable, non-invasive methods such as urine collection pads may be used, strictly following the manufacturer’s instructions. DO NOT use urine bags, cotton wool or gauze due to high risk of contamination.
• Urine samples should preferably be taken prior to starting antibiotics.
• If symptoms and signs highly suggestive of UTI and/or dipstick positive for leucocytes and/or nitrites, the urine should be sent for microscopy and culture.
  Note: Nitrites might be falsely negative in young infants and children who are not toilet trained as urine does not sit long in the bladder to form nitrites.
• In a severely unwell infant/ child, treatment should not be delayed if the urine sample is unobtainable.
• Urine samples for microscopy and culture should be collected in a red-top urine container (contains boric acid) and care taken to prevent overfilling (can destroy bacteria and cause false negative results). Ensure lid is replaced tightly (can leak and will not be processed).

Box 3: Urine Dipstick for diagnosis: (L = leucocyte esterase, N = Nitrites)

*See Box 5
Note: Leukocyte esterase positive on dipstick may be indicative of an infection outside the urinary tract in a febrile child which may need to be managed differently.

 Box 4: Interpretation or Urine Microscopy results in conjunction with culture

• Significant Pyuria > 10 x 10⁶ /L of urine; Bacteriuria is often referred to the bacteria on microscopy or on culture.

Urine Culture criteria for diagnosis:

• Urine culture is easier to interpret when urine sample is taken before antibiotics. 
• Confirmed UTI = Significant growth = pure growth >10⁵Colony forming units (CFU)/ml. Any growth on a urine from suprapubic aspirate is significant.
• Do NOT routinely repeat urine culture after finishing antibiotics, if the child has clinically improved.
• Do NOT [test urine (!) and] treat Asymptomatic Bacteriuria

Box 5. Urine samples should be sent for culture:

• Suspicion of acute pyelonephritis/upper UTI
• High to intermediate risk of serious illness/ Infants under 3 months
• In infants and children under 3 years: positive leukocyte esterase only (but specific signs of UTI present).
• High suspicion of UTI and/or underlying renal abnormality.**
• In infants and children with recurrent UTI.
• In infants and children with an infection that does not respond to treatment within 24 to 48 hours, if no sample has already been sent
• When clinical symptoms and dipstick tests do not correlate.

$$: Non-Ecoli pathogens may not induce significant pyuria. If high clinical suspicion of UTI, urine for culture must be sent and chased for definitive diagnosis.

Blood Tests:Full blood count, Urea, Electrolytes, Creatinine, Bicarbonate, Liver function tests, Calcium, Magnesium, Phosphate, CRP.

C-reactive protein alone should not be used to differentiate acute pyelonephritis/upper urinary tract infection from cystitis/lower urinary tract infection in infants and children.

Self-Care: General principles:

• Advise the parents/ carers to bring the child for reassessment if no response to treatment within 24 to 48 hours. 
• Advise drinking adequate fluids (such that urine is nearly colourless) to avoid dehydration or if vomiting/severely unwell, may need IV fluids.
• Paracetamol is safe for analgesia and if needed, could consider addition of codeine for children over 12 years. Avoid ibuprofen (can use cautiously with adequate hydration and no known underlying renal abnormality).
• Advise that children who have had a UTI should have ready access to clean toilets in school when required and should not be expected to delay voiding (a letter to school may be needed). 
• Ensure that they are aware of the possibility of a UTI recurring and the need to seek prompt treatment from a healthcare professional should this occur. 
• Explore and correct constipation, avoid bubble baths and tight synthetic underwear.
• Ensure correct wiping (front to back) after passing urine and complete emptying of bladder (double voiding, knees apart in girls especially if enuresis is present).
• In young boys the foreskin may be a source of infection and this area should be kept clean.

Antimicrobial Prescribing:  General Principles:

• Offer an antibiotic (if indicated) after sending urine for culture and sensitivities, if possible.
• Advise about its side effects of diarrhoea and nausea.
• When prescribing, oral route should be first choice for antibiotic administration. Exceptions: under 3 months of age, vomiting/severely ill child (will need IV antibiotics).
• Remember to check for any underlying serious renal pathology, previous urine cultures and sensitivities which may have led to resistant bacteria.
• Do not increase dose of prophylactic antibiotic (if child is on it). Start alternative antibiotic and discontinue the original prophylactic antibiotic.
• Use narrow spectrum antibiotic wherever possible.
• Review antibiotics at 48 hours. Consider switching from IV to oral if afebrile for 24 hours and clinically better. Change and/or add antibiotic if still unwell, based on urine culture and sensitivities.

Pyelonephritis/ Upper UTI: Antimicrobial Prescribing (See BNFc for doses)

• Trimethoprim may not be appropriate as the first choice of antibiotic if a diagnosis of pyelonephritis/Upper UTI is made.
• Nitrofurantoin is not suitable for treatment of pyelonephritis as it does not reach therapeutic concentrations in the kidney.
• Total Duration of treatment is 10 days (oral/IV+oral)
• Remember to review patient & urine culture, sensitivities at 48 hours; change antibiotic if no clinical improvement.

*Aminoglycosides (gentamicin) may be added if susceptibility/sepsis is a concern and/or fever not subsiding after 48 hours. Drug levels need to be monitored; ensure duration is 5 to 7 days only.

**Check previous isolates. If ESBL or multiresistant isolates including enterococcus; contact microbiologist for advice.

Use higher dose of Cefalexin, ie. 25mg/kg/dose

Warn parents about side effect of diarrhoea when prescribing co-amoxiclav.

Lower UTI/ Cystitis: Antimicrobial Prescribing (check BNFc for doses)

• Wherever possible, send urine for microscopy and culture before starting antibiotics.
• Total duration of antibiotics: 3 days (remember to review/change antibiotic if no improvement in 48 hours).

Management of Recurrent UTI  (includes antibiotic prophylaxis)

• Refer children and young people with recurrent UTI to a paediatric specialist for assessment and investigations.
• Recurrent UTI is often due to a functional/ structural abnormality of the urinary tract. Constipation may often be associated.
• There is insufficient evidence for effectiveness of antibiotic prophylaxis in reducing the risk of recurrent UTI/development or progression of renal scarring in children.
• However, antibiotic prophylaxis may be considered in children and young people under 16 years who have recurrent UTI, after treatment of current UTI but only under specialist advice when other management options (behavioural and personal hygiene) have been unsuccessful.
• Choice of antibiotic should be based on previous urine sensitivities, low risk of complications and patient preference.
• Risk of resistance and adverse effects of long-term antibiotics should be clearly explained to parents/carers.
• It is essential to base the decision for antibiotic prophylaxis on an assessment of underlying causes, taking into account the severity and frequency of previous symptoms and the risk of developing complications.
• Consider antibiotic prophylaxis at birth based on recommendations in antenatally detected, congenital renal anomalies guideline and liaise with paediatric surgeon/urologist as advised in the guideline: https://www.clinicalguidelines.scot.nhs.uk/ggc-paediatric-guidelines/ggc-guidelines/neonatology/renal-anomalies-detected-or-suspected-antenatally/

• Choice of antibiotics:

1^st choice:  Trimethoprim or nitrofurantoin: Children on nitrofurantoin prophylaxis should be monitored for liver function and pulmonary symptoms.

2^nd choice: Cefalexin or *amoxicillin (*off-label, not licensed for prevention of UTI)

• Review antibiotic prophylaxis every 6 months with an aim to stop if no urine infections in the last 6 months. For children needing prophylaxis for longer durations, specialist teams may discuss using different antibiotic every 6 months on a rotational basis, to prevent resistance.
• If antibiotic prophylaxis is stopped, ensure that the parents are aware of what symptoms and signs suggestive of UTI to look out for and have rapid access to treatment.
• Emphasise that this approach is not curative and they should still seek medical assessment if there are symptoms of UTI.
• Reiterate the principles of self-care at every review to reinforce strategies to prevent UTI.
• In addition, ensure parents
  • Promptly recognise the signs and symptoms of UTI
  • Are aware about correct method of urine collection
  • Have a spare red-top urine container and sterile bowl for collection if they have concerns about urine infection and submit this swiftly for preventing delay in diagnosis and management.
  • Understand the importance of completing treatment regimes and if on prophylaxis- to be compliant.
  • Are aware of the side-effects of the prescribed antibiotics and what to do if they develop.
  • Understand all treatment options as well as the nature and reason of any urinary tract investigation.

Important considerations & Interpretations:

• Renal ultrasound in the continent child should always be requested with pre and post void urine volumes. This is vital for the assessment of the bladder.
• Renal ultrasound cannot conclusively rule out renal scarring.
• If requesting a DMSA/MAG3, please consider blood tests at the time of cannulation (complete request forms) for FBC, U&E, Bicarbonate, LFTs, Calcium, Magnesium, Phosphate, urate, checking weight, height, blood pressure, urine protein:creatinine ratio and document them on ward attender sheet.
• MCUG and/or DMSA should only be considered when the UTI was considered “upper” UTI (ie. associated with fever: 38°C or greater, symptoms of UTI and bacteriuria and especially if abnormal renal ultrasound).
• DMSA is not recommended after a single febrile UTI if typical bacteria, clinical response within 48 hours of treatment and a normal renal ultrasound.
• DMSA findings are especially significant when the difference in relative function of the kidneys is greater than 10%.
• If atypical UTI but no systemic symptoms including fever are present and/or, not a recurrent UTI and normal renal ultrasound- do not do a DMSA/MCUG.
• Diagnosis of permanent scars is better at 6 months as opposed to 4 months after an UTI. If UTI occurs again before DMSA is done, consider doing the DMSA earlier (will need a special request to Nuclear Medicine Consultant at Raigmore usually via an email).
• MCUG should usually be considered only if Renal ultrasound and/or DMSA is abnormal. MAG3 may be preferable when screening for VUR in continent or older children as they can void on demand.
• On requesting MCUG:A3 day treatment course of antibiotics (usually trimethoprim unless resistant- then use other alternative antibiotic) is prescribed when MCUG is arranged with the MCUG taking place on the 2^nd day of the treatment course. There is a template in Renal folder on intranet to post out to parents.
• Plain X-ray abdomen is rarely indicated. It may be requested by specialist colleagues when assessing for renal/ureteric stones.
• MRU (Magnetic resonance Urography) may be occasionally requested by specialist colleagues.

Recommended imaging schedule for infants younger than 6 months

a - see box 1 for definition
b - If abnormal consider MCUG
c - In an infant or child with non-E.coli-UTI, responding well to antibiotics and with no other features of atypical infection, the ultrasound can be requested on a non-urgent basis to take place within 6 weeks

Recommended imaging schedule for infants and children 6 months or older but younger than 3 years

a - see box 1 for definition
b - While MCUG should not be performed routinely it should be considered if the following features are present:

• dilation on ultrasound
• poor urine flow
• non-E. coli-infection
• family history of VUR

c - In an infant or child with non-E.coli-UTI, responding well to antibiotics and with no other features of atypical infection, the ultrasound can be requested on a non-urgent basis to take place within 6 weeks

Recommended imaging schedule for children 3 years or older

a - see box 1 for definition
b - Ultrasound in toilet-trained children should be performed with a full bladder with an estimate of bladder volume before and after micturition.
c - In an infant or child with non-E.coli-UTI, responding well to antibiotics and with no other features of atypical infection, the ultrasound can be requested on a non-urgent basis to take place within 6 weeks

FOLLOW UP:

• After the first UTI:  no routine follow-up if all the imaging is normal. It should be agreed with parents/carers that the results would be communicated to the parents in writing.
• Infants and children who have recurrent UTI or abnormal imaging results should be assessed by a paediatric specialist. There should be emphasis on self-care in all appointments.
• Infants and children who have bilateral renal abnormalities, impaired kidney function, raised blood pressure and/or proteinuria should receive monitoring and appropriate management by a paediatric nephrologist/paediatrician with renal interest, to slow the progression of chronic kidney disease.
• Assessment of infants and children with renal parenchymal defects should include height, weight, blood pressure and routine testing of early morning urine for proteinuria. Be aware of age, gender and height centile based BP charts for children.

2016 European Society of Hypertension guidelines for the Classification of hypertension in children and adolescents.

2016 European Society of Hypertension guidelines for the management of high blood pressure in children and adolescents.  Lurbe et al. J Hypertens 34:1887–1920.

BP charts in children (boys and girls)

https://pediatrics.aappublications.org/content/pediatrics/early/2017/08/21/peds.2017-1904.full.pdf