Urinary tract infection (UTI) in children
CKS UTI in children
Definition
Urinary tract infection (UTI) is illness caused by micro-organisms in the urinary tract.
Prevalence
Around 1 in 10 girls and 1 in 30 boys will have had a UTI by the age of 16 years.
2.1% of girls and 2.2% of boys will have had a UTI before the age of 2 years.
Cumulatively, 5% of children aged less than 5y met laboratory criteria for UTI
Risk Factors
Most UTIs are caused by bacteria from the gastrointestinal tract.
Common organisms causing UTI in children include Escherichia coli (about 85% or more of cases), Proteus, Klebsiella species, and Staphylococcus saprophyticus.
Female sex — however, in the first three months of life, UTI is more common in boys than girls.
Previous UTI
Voiding dysfunction
Sexual activity
Sexual abuse
No history of breastfeeding
Immunosuppression
Complications
Acute: Pyelonephritis should be suspected in all children with unexplained fever of 38°C or more, or loin pain/tenderness.
Long-term: Renal scarring, hypertension, renal failure, pre-eclampsia
Renal scarring/damage
Around 5% of children presenting with first-time UTI will have renal parenchymal defects on imaging.
Approximately 25% of children aged less than 6 years with first-time UTI have Vesicoureteral reflux VUR, and of those, 25% have significant VUR (grade IV or V), placing them at risk for renal scarring.
The prevalence of VUR in the general population is 1–3%.
Symptoms and Signs of UTI
Pyelonephritis
fever of 38°C or more
loin pain/tenderness.
UTI and age>3m
fever
frequency
dysuria
abdominal pain, loin tenderness
vomiting
poor feeding
dysfunctional voiding
changes to continence
UTI and age<3m
fever
vomiting
lethargy or irritability
poor feeding
failure to thrive
Assessment and management
Make an assessment of the risk of serious illness in all children with suspected urinary tract infection (UTI) — if the risk is high, refer urgently to secondary care.
Age<3m and suspected UTI
Refer urgently to a paediatric specialist for treatment with parenteral antibiotics, and send a urine sample for urgent microscopy and culture.
Age>3m then undertake dipstick urine analysis
If both leukocyte esterase and nitrite are positive, treat as UTI (start antibiotic treatment, send urine for culture)
If both leukocyte esterase and nitrite are negative, UTI is unlikely (consider differential diagnosis, send urine if intermediate-risk features identified)
If leukocyte esterase is positive and nitrite is negative, treat as UTI (start antibiotic treatment age<3y and age>3yr if supporting clinical evidence, send urine for culture).
If leukocyte esterase is negative and nitrite is positive, treat as UTI (start antibiotic treatment, send urine for culture)
Acute pyelonephritis/upper UTI should be diagnosed in children with a fever of 38°C or higher and bacteriuria, or a fever lower than 38°C with loin pain/tenderness and bacteriuria.
All ages and suspected acute pyelonephritis/upper UTI
Unexplained fever of 38ºC or higher, or loin pain/tenderness, and bacteriuria —>suggests pyelonephritis —send urine for culture and urgent referral to paediatrics
and oral antibiotic treatment should be started, with either cefalexin, or co-amoxiclav.
Antibiotic treatment for cystitis/lower UTI (age>3m)
oral trimethoprim
oral nitrofurantoin (if eGFR ≥ 45ml/minute)
or amoxicillin (only if culture results available and susceptible)
or cefalexin.
Daily antibiotic prophylaxis should be considered for children affected by recurrent UTI
Renal investigations
Renal ultrasound: Within 6 weeks, for all children younger than 6 months of age with first-time UTI that responds to treatment.
Ensure that a dimercaptosuccinic acid scintigraphy (DMSA) scan to detect renal parenchymal defects is carried out within 4–6 months following the acute infection in all children with recurrent UTI
Risk of serious illness in a child with suspected urinary tract infection
A low-risk of serious illness
Absent high- or intermediate-risk features
Normal colour of skin, lips and tongue
Normal response to social cues
Content/smiling
Staying awake or waking quickly
Strong normal cry
Normal skin and eyes
Moist mucous membranes
Age<5yr and intermediate-risk of serious illness
Temperature ≥39°C infant aged 3–6 months
Rigors
Pallor of skin, lips or tongue reported by parent or carer.
Not responding normally to social cues.
Not smiling.
Waking only with prolonged stimulation.
Decreased activity.
Tachycardia
HR >160 bpm age <12m
HR>150 bpm age 12–24m
HR>140 bpm age 2–5y
Tachypnoea, Nasal flaring.
RR>50 age 6–12m
RR>40 age>12m
Dry mucous membranes.Poor feeding in infants.
Reduced urine output.
CRT ≥3s
Age<5yr and high-risk of serious illness
Temperature ≥38°C age<3m.
Pale/mottled/ashen/blue skin, lips, or tongue
No response to social cues
Appearing ill to a healthcare professional.
Not waking, or if roused not staying awake
Weak, high-pitched or continuous cry
Grunting
RR>60
Moderate or severe chest indrawing
Reduced skin turgor
Bulging fontanelle
Collection and storage of urine samples
In infants and toddlers, obtain a clean catch urine (CCU) sample — gentle suprapubic cutaneous stimulation using gauze soaked in cold fluid helps trigger voiding.
Potties cleaned in hot water with washing up liquid may be used.
Other non-invasive methods include urine collection pads.
When it is not possible or practical to collect urine by non-invasive methods, catheter samples or suprapubic aspiration (SPA) (with ultrasound guidance) should be used.
Specimens should be transported and processed within 4 hours unless boric acid preservative is used — if this is not possible it should be refrigerated at 4°C.
Differential diagnoses of UTI
Interstitial cystitis — urinary frequency, urgency, bladder pain with relief on voiding.
Kawasaki disease — rash, mucositis, extremity swelling, cervical lymph node swelling, conjunctivitis. 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. There may be a history of sexual activity/abuse, and/or use of bubble baths.
Although it is rare, clinicians should be alert to the possibility of child abuse presenting with urinary symptoms.
Consider sexual abuse if a girl or boy has dysuria (discomfort on passing urine) or ano-genital discomfort that is persistent or recurrent and does not have a medical explanation (such as threadworms, urinary infection, skin conditions, poor hygiene, or known allergies).