History and exam

Key diagnostic factors

common

fever >102.2°F (>39°C)

Higher fever and fever duration >24 hours increase the likelihood of UTI in infants.[39][60]

Absence of high fever does not preclude the presence of UTI.[61]

The overall prevalence of UTI in children <2 years of age with an undifferentiated febrile illness is approximately 5%.[12]

irritability (neonates and infants)

Signs and symptoms in infants with serious bacterial infection may be subtle.

poor feeding (neonates and infants)

Neonates with UTI often present with very nonspecific symptoms.

suprapubic tenderness

In infant girls, may be the only helpful sign for making the diagnosis of UTI (positive likelihood ratio 4.4).[39]

uncommon

costovertebral angle tenderness

May be seen with pyelonephritis and renal capsular stretch.

Other diagnostic factors

common

foul-smelling urine (infants, older children, and adolescents)

May be secondary to increased urine urea concentration.

In previous studies, it has not been shown to have increased predictive value.[39]

dysuria (preschool age, older children, and adolescents)

Increases the likelihood of a UTI (positive likelihood ratio range 2.2 to 2.8) in patients able to verbalize.[39]

urinary frequency (older children and adolescents)

Older children and adolescents are more likely to have symptoms that are more specific to the urinary system.

abdominal/flank pain (infants, older children, and adolescents)

Increases the likelihood of a UTI (positive likelihood ratio 6.3) in patients able to verbalize.[39]

uncommon

vomiting

May occur in all ages and can result in dehydration.

Toddlers may also have diarrhea.

In older children, systemic symptoms such as fever, abdominal or flank pain, and vomiting are highly suggestive of pyelonephritis.

ill appearance (neonates)

Neonates may appear mottled, or have vital sign instability, decreased activity, and poor oral intake.

Signs and symptoms in infants with serious bacterial infection may be subtle.

gross hematuria (older children and adolescents)

Older children and adolescents are more likely to have symptoms that are more specific to the urinary system.

new-onset urinary incontinence (toddlers, older children, and adolescents)

Increases the likelihood of a UTI (positive likelihood ratio 4.6) in patients able to verbalize.[39]

Risk factors

strong

age <1 year

Infant boys <3 months of age and infant girls <1 year show the highest prevalence rates.[10]

female sex

UTI is more common in girls than in boys after 12 months of age.[13]

The most likely etiology is shorter urethral length for ascension of periurethral bacteria.

uncircumcised boys in the first year of life

Have a >8-fold higher incidence than circumcised boys.[23]

Presence of the foreskin allows for easier bacterial colonization of the periurethral region.

previous UTI

Approximately 78% of girls and 71% of boys presenting with UTI within the first year of life experienced recurrence. After their first year of life, 45% of girls and 39% of boys developed further infections.[24]

Previous UTI is one of the most useful historical factors for diagnosis of UTI in infants.

bladder and bowel dysfunction

Children with bladder and bowel dysfunction (BBD) have a twofold increased risk of recurrent UTI.[25] BBD is associated with an increased risk of renal scarring following a febrile UTI.[26] BBD increases the risk of breakthrough febrile UTI in children with vesicoureteral reflux.[27] 

BBD is very common and likely underdiagnosed.[19] It is estimated that BBD represents approximately 40% of pediatric urology visits.[28]

BBD is a functional condition that describes a constellation of lower urinary tract symptoms associated with functional constipation and/or encopresis. Children with BBD have no recognizable neurologic or anatomic abnormality.[19] The increased fecal load affects bladder dynamics by both direct mechanical compression and by changing neural stimuli on the bladder and pelvic floor muscles.[28] Symptoms include urinary storage symptoms (incontinence, increased or decreased voiding frequency, urgency, nocturia); urinary voiding symptoms (hesitancy, straining, weak stream, intermittent micturition, dysuria); holding maneuvers to postpone micturition (e.g., standing on tiptoe, forcefully crossing legs, pushing on the genitals or abdomen); a feeling of incomplete bladder emptying; pain in the bladder, urethra, or genitals; fecal incontinence and constipation.[19][29]

vesicoureteral reflux

Approximately 25% of children with first-time UTI have vesicoureteral reflux (VUR).[30] VUR has been detected in 41.7% of neonates admitted to hospital with a UTI.[31]

sexual activity

In adolescent girls there is an increased relative risk in response to increased frequency of sexual intercourse.[32] Symptoms of urethritis caused by sexually transmitted infections may mimic UTI in both sexes.

Sexual abuse can cause urinary symptoms in girls, but infection is uncommon.[33]

no history of breastfeeding

Breastfeeding has a protective effect, which is more pronounced in infant girls.

This depends on the duration of breastfeeding, and the effect appears to persist even after weaning.[34]

anatomic abnormalities or previous surgery to the urinary tract

Obstructive anomalies have been found in up to 4% of children with first-time UTI.[35]

Obstructive anomalies include ureteropelvic junction (UPJ) obstruction, obstructive megaureter, posterior urethral valves, and ureterocele. Other anatomic abnormalities that predispose to UTI include urachal remnant, nephrolithiasis, and duplicated collecting system.[7]

May have atypical (non-Escherichia coli) bacteria as the cause of their UTI.

weak

immunosuppression

Patients are susceptible to candidal UTIs in addition to bacterial UTIs.

protein-energy malnutrition

Malnourished children have a twofold increased risk of UTI compared with healthy children. One meta-analysis reported a pooled prevalence of UTI of 17% in malnourished children.[36]

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