Urology
Question 64 of 180
The parents of a 2 month old girl bring her to the Emergency Department as they are concerned about a fever. They describe her as being "irritable" and have been struggling to get her to feed. They have noted she has a reduced number of wet nappies and that they smell offensive. Her observations are recorded as:
- Heart rate: 152 beats/minute
- Respiratory rate: 40 breaths/minute
- Temperature: 37.8°C
- Central capillary refill: 2 seconds
A urine dipstick is positive for both leucocytes and nitrite. Which of the following is the most appropriate management step for this child?
Answer:
If UTI is suspected in children aged under 3 months — refer urgently to a paediatric specialist for treatment with parenteral antibiotics, and send a urine sample for urgent microscopy and culture.Paediatric Urinary Tract Infection
Urology
Last Updated: 12th February 2021
Urinary tract infection (UTI) is an illness caused by microorganisms in the urinary tract.
- Lower UTI (cystitis) affects the bladder and urethra.
- Upper UTI (pyelonephritis) affects the renal pelvis and kidneys.
Causes
Bacterial causes of urinary tract infection (UTI) in children and young people include:
- Escherichia coli — thought to cause 85–90% of paediatric UTIs.
- Proteus mirabilis — found in 30% of boys with uncomplicated cystitis.
- Staphylococcus saprophyticus — found in adolescents of both sexes with acute UTI.
- Pseudomonas species, Serratia marcescens, Citrobacter species, and Staphylococcus epidermidis — may cause low-virulence infections if there is urinary tract malformation or dysfunction.
- UTI in children can also be caused by Klebsiella aerogenes and Enterococcus species.
- Adenovirus infections are also a rare cause of UTI.
- Candidal UTI can occur in people who are immunosuppressed.
Risk factors
Risk factors for urinary tract infection (UTI) in children and young people include:
- Age below one year.
- Female sex — however, in the first three months of life, UTI is more common in boys than girls.
- White children.
- Previous UTI.
- Voiding dysfunction — may be caused by factors such as structural abnormalities, neurogenic bladder, voluntary withholding of urine (dysfunctional elimination syndrome), chronic constipation, or indwelling foreign bodies.
- Vesicoureteral reflux (VUR), family history of VUR or renal disease — VUR is reflux of urine from the bladder into a ureter. It can be unilateral or bilateral. Approximately 25% of children aged less than 6 years with first-time UTI have VUR, and of those, 25% have significant VUR (grade IV or V), placing them at risk for renal scarring.
- Sexual activity — in adolescent girls, there is an increased relative risk in response to increased frequency of sexual intercourse.
- Sexual abuse can cause urinary symptoms, but infection is uncommon.
- Immunosuppression.
Complications
Possible complications of childhood UTI include:
- Renal scarring/damage:
- Around 5% of children presenting with first-time UTI will have renal parenchymal defects on imaging. Renal scarring is almost always preceded by an upper UTI (acute pyelonephritis), although not all upper UTIs are followed by renal scarring. Renal scarring is more common in children with vesicoureteral reflux (VUR) and is most common with the most severe grades. VUR is both a cause of acute pyelonephritis and a compounder of its effects.
- Hypertension:
- Hypertension may be associated with UTI in childhood, but the risk is likely to be small and clinically important only if the child has severe or bilateral renal scarring.
- Bacteriuria and hypertension in pregnancy; pre-eclampsia:
- Limited data suggest that pregnant women who have a history of childhood UTI are at increased risk of bacteriuria, and renal scarring (especially more severe or bilateral renal scarring) may be associated with an increase in hypertension and pre-eclampsia during pregnancy.
- Renal insufficiency and failure:
- Childhood UTI appears to be associated with a small increased risk of established renal failure (ERF) during childhood or early adulthood. Adult disease, therefore, may also relate to childhood UTI. However, chronic renal failure/insufficiency without ERF may be a much more common outcome.
Clinical features
- Suspect pyelonephritis in:
- All children with unexplained fever of 38°C or more, or loin pain/tenderness.
- Suspect lower urinary tract infection (UTI) in children aged under 3 months with signs and symptoms, including:
- Fever, vomiting, lethargy, irritability, poor feeding or failure to thrive.
- Less common symptoms include abdominal pain, jaundice, haematuria and/or offensive urine.
- Suspect lower UTI in children aged 3 months or over with signs and symptoms, including:
- Fever, frequency, dysuria, abdominal pain, loin tenderness, vomiting, poor feeding, dysfunctional voiding, changes to continence.
- Less common symptoms include lethargy, irritability, haematuria, offensive urine, failure to thrive, malaise, cloudy urine.
Assessment
- Make an assessment of the risk of serious illness in all children with suspected urinary tract infection (UTI). To assess the risk of serious illness in an infant or child, carry out an examination, including measurement of temperature, respiratory rate, heart rate, and capillary refill time. Observe effort of breathing, and pay attention to the colour of the skin, lips, and tongue, and the appearance of the mucous membranes.
- For all children presenting with an unexplained fever of 38ºC or higher, or loin pain/tenderness suggesting pyelonephritis — send a urine sample for microscopy and culture within 24 hours, and consider referral to a paediatric specialist.
- Diagnose acute pyelonephritis/upper UTI in children with:
- A fever of 38°C or higher and bacteriuria.
- A fever lower than 38°C with loin pain/tenderness and bacteriuria.
- All other infants and children who have bacteriuria but no systemic symptoms or signs should be considered to have cystitis/lower UTI.
- If UTI is suspected in children aged under 3 months — refer urgently to a paediatric specialist for treatment with parenteral antibiotics, and send a urine sample for urgent microscopy and culture.
- If UTI is suspected in children aged 3 months or over — perform dipstick analysis:
- If both leukocyte esterase and nitrite are positive, treat as a UTI.
- Start antibiotic treatment.
- Send a urine sample for culture if the child is aged under 3 years, has a high or intermediate risk of serious illness, symptoms suggest acute pyelonephritis/upper UTI, a previous UTI, or there has been no response to treatment and a urine sample has not already been sent.
- If both leukocyte esterase and nitrite are negative, UTI is unlikely.
- Do not start antibiotic treatment. Consider differential diagnoses.
- Send a urine sample for culture if the child has a high or intermediate risk of serious illness, symptoms suggest acute pyelonephritis/upper UTI, UTI is recurrent, there has been no response to treatment within 24–48 hours and a urine sample has not already been sent, or clinical symptoms and dipstick tests do not correlate.
- If leukocyte esterase is positive and nitrite is negative, send a urine sample for microscopy and culture.
- For children aged under 3 years, start antibiotic treatment and reassess once culture results are known.
- For children aged 3 year or over, only start antibiotic treatment if there is good clinical evidence of UTI (leucocytes may indicate infection outside the urinary tract).
- If leukocyte esterase is negative and nitrite is positive, treat as a UTI.
- Start antibiotic treatment if dipstick test was with a fresh urine sample (repeat urine test if not fresh, as old samples can give false positives).
- Send urine for culture to confirm diagnosis and reassess once results are known.
- If both leukocyte esterase and nitrite are positive, treat as a UTI.
- Do not delay treatment in a child with a high risk of serious illness if a urine sample cannot be obtained.
Differential diagnosis
The differential diagnoses of urinary tract infection include:
- Interstitial cystitis — urinary frequency, urgency, bladder pain with relief on voiding.
- Kawasaki disease — rash, mucositis, extremity swelling, cervical lymph node swelling, conjunctivitis (however, no signs may be present in those below 6 months of age). Sterile pyuria present on urine microscopy.
- Meningitis — photophobia, rash, neck stiffness.
- Nephrolithiasis — colicky pain, family history, passing of particulate matter in the urine.
- Sepsis with no urinary tract source — jaundice and haemodynamic instability.
- Threadworms — perianal itching.
- Urethritis — urethral discharge, pelvic pain.
- Voiding dysfunction — urine withholding behaviours (squatting, 'Vincent curtsy', physical holding), urgency, frequency, incontinence.
- Vulvovaginitis or vaginal foreign body — vaginal discharge.
- Although it is rare, clinicians should be alert to the possibility of child abuse presenting with urinary symptoms.
Management
- If the child has been assessed at high risk of serious illness, refer urgently to paediatric specialist.
- Suspected UTI in children aged under 3 months
- If UTI is suspected in children aged under 3 months — refer urgently to a paediatric specialist for treatment with parenteral antibiotics, and send a urine sample for urgent microscopy and culture.
- Suspected upper UTI/pyelonephritis in children > 3 months
- Consider referral to a paediatric specialist. Use clinical judgement to determine whether this is necessary.
- Start oral antibiotic treatment with cefalexin, or co-amoxiclav (only if culture results are available and susceptible).
- Suspected lower UTI/cystitis in children > 3 months
- Start oral antibiotic treatment — first line options include trimethoprim (if there is low risk of resistance), or nitrofurantoin (if eGFR ≥ 45 ml/minute).
- Provide parents or carers with information and advice:
- Advise the parents or carers to bring the child for reassessment if they do not respond to treatment within 24–48 hours. .
- Outline the importance of completing any course of treatment.
- Advise use of paracetamol for pain relief where required.
- Advise on adequate fluid intake to avoid dehydration.
- Advise that children who have had a UTI should have ready access to clean toilets when required and should not be expected to delay voiding.
- 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.
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- Biochemistry
- Blood Gases
- Haematology
| Biochemistry | Normal Value |
|---|---|
| Sodium | 135 – 145 mmol/l |
| Potassium | 3.0 – 4.5 mmol/l |
| Urea | 2.5 – 7.5 mmol/l |
| Glucose | 3.5 – 5.0 mmol/l |
| Creatinine | 35 – 135 μmol/l |
| Alanine Aminotransferase (ALT) | 5 – 35 U/l |
| Gamma-glutamyl Transferase (GGT) | < 65 U/l |
| Alkaline Phosphatase (ALP) | 30 – 135 U/l |
| Aspartate Aminotransferase (AST) | < 40 U/l |
| Total Protein | 60 – 80 g/l |
| Albumin | 35 – 50 g/l |
| Globulin | 2.4 – 3.5 g/dl |
| Amylase | < 70 U/l |
| Total Bilirubin | 3 – 17 μmol/l |
| Calcium | 2.1 – 2.5 mmol/l |
| Chloride | 95 – 105 mmol/l |
| Phosphate | 0.8 – 1.4 mmol/l |
| Haematology | Normal Value |
|---|---|
| Haemoglobin | 11.5 – 16.6 g/dl |
| White Blood Cells | 4.0 – 11.0 x 109/l |
| Platelets | 150 – 450 x 109/l |
| MCV | 80 – 96 fl |
| MCHC | 32 – 36 g/dl |
| Neutrophils | 2.0 – 7.5 x 109/l |
| Lymphocytes | 1.5 – 4.0 x 109/l |
| Monocytes | 0.3 – 1.0 x 109/l |
| Eosinophils | 0.1 – 0.5 x 109/l |
| Basophils | < 0.2 x 109/l |
| Reticulocytes | < 2% |
| Haematocrit | 0.35 – 0.49 |
| Red Cell Distribution Width | 11 – 15% |
| Blood Gases | Normal Value |
|---|---|
| pH | 7.35 – 7.45 |
| pO2 | 11 – 14 kPa |
| pCO2 | 4.5 – 6.0 kPa |
| Base Excess | -2 – +2 mmol/l |
| Bicarbonate | 24 – 30 mmol/l |
| Lactate | < 2 mmol/l |
