[04.14] PED - UTI in Children V2.1 .pdf

Children under 1 year of age

In which pediatric age group are urinary tract infections most common?

7%

What is the prevalence of UTI in febrile children younger than 24 months?

8%

What is the prevalence of UTI in older children up to 19 years of age presenting with fever or urinary symptoms?

Uncircumcised febrile males

In the first 3 months of life, which subgroup of infants has the highest prevalence of UTI?

20%

What is the prevalence of UTI in uncircumcised febrile males during the first 3 months of life?

8 times higher

How much higher is the UTI prevalence in uncircumcised males compared to circumcised males during the first 3 months of life?

2 to 3 times higher

How much higher is the UTI prevalence in uncircumcised males compared to females during the first 3 months of life?

Females

After 6 months of age, which sex experiences a higher likelihood of UTIs?

Infancy, toilet training, and the onset of sexual activity

What are the three peak periods for UTI occurrence in females after 6 months of age?

Younger children present with more nonspecific symptoms, whereas older children present with specific symptoms referable to the urinary tract

How does the presentation of UTI symptoms vary by age in pediatric patients?

2 years of age

What age serves as the clinical cutoff for initiating a more extensive work-up due to a child's ability to verbalize localized pain?

The younger the patient, the greater the likelihood of missing a UTI

What is the relationship between a patient's age and the risk of missing a UTI diagnosis?

Acute pyelonephritis

Which classification of UTI refers to an upper urinary tract infection involving the renal parenchyma?

Cystitis

Which classification of UTI refers to a lower urinary tract infection limited strictly to the bladder?

Abdominal pain, back pain, flank pain, fever, malaise, nausea, vomiting, and occasionally diarrhea

What are the characteristic clinical symptoms of pyelonephritis?

High fever (≥39°C) lasting >48 hours without an identifiable source

What is often the sole clinical manifestation of pyelonephritis in infants and young children?

Poor feeding, irritability, jaundice, and weight loss

What non-specific clinical signs characterize pyelonephritis in newborns?

Renal scarring, which can progress to hypertension and end-stage renal disease (ESRD)

What long-term parenchymal complications can result from recurrent or severe pyelonephritis?

Dysuria, urgency, frequency, suprapubic pain, incontinence, and malodorous urine

What clinical symptoms characterize cystitis in pediatric patients?

Cystitis

Which type of UTI does NOT cause high fever and does NOT result in renal parenchymal injury or scarring?

Febrile UTIs

Which clinical presentation of UTI is specifically associated with a higher likelihood of causing permanent renal scars?

Urinalysis

What is the most frequently requested initial diagnostic screening test for a suspected UTI?

Clean the introitus in toilet-trained females and retract the prepuce in uncircumcised males

What preparation steps are required when obtaining a mid-stream clean catch urine specimen?

Catheterized urine collection

What is the recommended collection method for non-toilet-trained children aged 2 to 24 months?

Suprapubic tap

Which invasive urine collection method is best suited for children under 1 year of age and considers any bacterial growth significant?

Any bacterial growth

What colony count threshold indicates a significant result on a suprapubic tap collection?

It is reliable ONLY if the culture and urinalysis results are negative

What is the primary diagnostic rule regarding the reliability of a bag urine collection?

The positive result must always be confirmed with a catheterized or clean catch specimen due to high contamination risk

What action must be taken if a bag urine collection yields a positive result?

Bacteriuria, pyuria, positive nitrites, and positive leukocyte esterase test

What four key urinalysis findings strongly suggest the presence of a UTI?

Nitrite test

Which individual urine dipstick test possesses the highest specificity for detecting a UTI?

98% (range 90–100%)

What is the specificity of the urine nitrite test for UTI?

53% (range 15–82%)

What is the sensitivity of the urine nitrite test?

83% (range 67–94%)

What is the sensitivity of the leukocyte esterase test?

78% (range 64–92%)

What is the specificity of the leukocyte esterase test?

Positive leukocyte esterase test OR positive nitrite test

Which combination of dipstick parameters provides a sensitivity of 93% (90–100%)?

Positive leukocyte esterase test, positive nitrite test, OR positive microscopy

Which combination of urinalysis tests provides the highest overall diagnostic sensitivity of 99.8%?

70% (range 60–92%)

What is the specificity when combining positive leukocyte esterase, nitrite, or microscopy?

Sensitivity of 73% and specificity of 81%

What are the sensitivity and specificity of urine microscopy for white blood cells?

Sensitivity of 81% and specificity of 83%

What are the sensitivity and specificity of urine microscopy for bacteria?

Escherichia coli

What is the most common bacterial pathogen causing pediatric UTIs?

Approximately 80%

What percentage of pediatric UTIs is caused by Escherichia coli?

Klebsiella spp., Proteus spp., Enterobacter spp., and Citrobacter spp.

What Gram-negative bacterial pathogens other than E. coli cause UTIs in children?

Staphylococcus saprophyticus, Enterococcus spp., Group B Streptococcus, and Staphylococcus aureus

What Gram-positive bacterial pathogens cause UTIs in pediatric patients?

Adenovirus, Enterovirus, Coxsackievirus, and Echovirus

Which viral pathogens can cause UTIs in children?

Cystitis (lower urinary tract infection)

To which anatomical region of the urinary tract are viral UTIs usually limited?

Candida spp., Aspergillus spp., Cryptococcus neoformans, and endemic mycoses

Which fungal pathogens can cause UTIs in pediatric patients?

Immunosuppression, long-term broad-spectrum antibiotic therapy, and indwelling urinary catheters

What are three major risk factors for developing a fungal UTI in children?

50,000 colony-forming units (CFU)/mL of a single uropathogen

What standard urine culture colony count threshold is recommended to confirm a UTI in a symptomatic child?

10,000 CFU/mL

In an appropriate clinical context or restricted lab reporting, what lower colony count threshold may be sufficient to diagnose a UTI?

Ascending infection from perineal flora entering the bladder via the urethra

What is the predominant mechanism by which nearly all UTIs develop in children?

Bacterial flora colonizing beneath the prepuce

What is the anatomical origin of bacterial pathogens causing ascending UTIs in uncircumcised males?

Hematogenous spread

By what rare route can renal infections occur in neonates with bacteremia or patients with endocarditis?

Simple and compound papillae

What anatomical structures in the kidney normally feature an antireflux mechanism preventing pelvic urine from entering collecting tubules?

Upper and lower poles of the kidney

In which anatomical regions of the kidney do compound papillae permit intrarenal reflux?

Periurethral area

Which region is initially colonized by uropathogens prior to uroepithelial penetration?

Fimbria

Which bacterial structural appendages facilitate adherence and penetration into bladder uroepithelial cells as well as ascension up the ureters?

Biofilms

What protective bacterial aggregates can form following uroepithelial penetration within the bladder?

Bacterial toxins

Which bacterial factors inhibit ureteral peristalsis to promote the ascension of uropathogens?

Interstitial edema, interstitial nephritis, and acute kidney injury (AKI)

What renal parenchymal pathology results from tubular obstruction and inflammatory damage during pyelonephritis?

Unobstructed urine transport, unidirectional urine flow, operative antimicrobial urothelial activity, regular complete bladder emptying, and normal perineal resistance

What five host mechanisms protect the urinary tract from bacterial infection?

Kidney -> pelvo-calyceal system -> ureter -> bladder

What is the correct pathway for unidirectional urine flow through the urinary tract?

Urolithiasis, intrarenal reflux, vesicoureteral reflux (VUR), obstructive uropathy, defective urothelial defense, imbalanced voiding, diverticula, and periurethral colonization

What host abnormalities potentiate the establishment of an invasive bacterial UTI?

Stagnant urine within diverticula

Why do bladder diverticula act as a potentiating factor for urinary tract infections?

Soilage (diaper wetting/encopresis), periurethral inflammation (diaper rash/bubble baths/harsh soaps), and phimosis

What factors contribute to periurethral bacterial colonization?

Onset of toilet training

At what developmental milestone do UTIs frequently occur in females due to bowel-bladder dysfunction?

High-pressure, turbulent urine flow and incomplete bladder emptying

How do uninhibited bladder contractions during voluntary urine withholding promote bacteriuria?

Refusal to use school bathrooms due to hygiene concerns, causing urinary retention

What behavior in school-age children precipitates bowel-bladder dysfunction?

It causes urinary stasis, providing an ideal culture medium for uropathogens

Why does obstructive uropathy leading to hydronephrosis increase UTI risk?

Fecal impaction compresses the bladder, causing bladder dysfunction and incomplete emptying

How does severe constipation increase the risk of developing a UTI?

Stagnant urine

What is the primary underlying physical factor that serves as an excellent culture medium for uropathogens?

Posterior urethral valves

What is the most common anatomic postrenal cause of urinary tract obstruction in children?

Ureteropelvic junction (UPJ) obstruction

What upper urinary tract anatomic anomaly causes urinary stasis and pre-disposes to UTI?

Myelomeningocele with a neurogenic bladder

What neurologic condition causes functional urinary stasis and predisposes children to UTIs?

1% to 4%

What is the prevalence of obstructive anatomic abnormalities in children presenting with their first UTI?

Daytime enuresis or urine dribbling, family history of urologic abnormalities, abnormal GU physical exam findings, and failure to respond to appropriate antibiotics

What four clinical features should raise suspicion for an underlying urinary obstruction in a child with UTI?

Bladder and bowel dysfunction (BBD)

What functional disorder involving behavioral abnormalities of pelvic, bladder, and sphincter muscles causes daytime wetting and constipation?

40%

What percentage of toilet-trained children presenting with their first UTI report symptoms of bladder and bowel dysfunction?

80%

What percentage of children with recurrent UTIs (3 or more) report symptoms of bladder and bowel dysfunction?

Persistent vesicoureteral reflux (VUR), kidney scarring, and recurrent UTIs

What long-term renal complications are associated with bladder and bowel dysfunction?

Sexual activity and increasing duration of bladder catheterization

What additional behavioral and medical risk factors increase the risk of UTI?

Leukocytosis and neutrophilia on CBC; elevated ESR, C-reactive protein (CRP), and procalcitonin

What laboratory markers of systemic inflammation accompany acute pyelonephritis?

3% to 20%

What is the reported incidence of bacteremia in children presenting with pyelonephritis?

Infants under 60 days of age and ill-appearing patients

In which pediatric patient groups should blood cultures be routinely obtained prior to starting antibiotics for pyelonephritis?

High-grade vesicoureteral reflux (VUR)

Which degree of VUR carries the highest risk for developing permanent kidney scars after a UTI?

Odds ratio of 1.8 (95% CI 1.2–2.8)

What is the odds ratio for developing kidney scars in patients with Grade I and II VUR?

Odds ratio of 22.5 (95% CI 11.3–44.8)

What is the odds ratio for developing kidney scars in patients with Grade IV and V VUR?

Odds ratio of 3.8 (95% CI 2.6–5.5)

What is the odds ratio for kidney scarring associated with an abnormal kidney-bladder ultrasound (KBUS)?

C-reactive protein (CRP) > 40 mg/L (or > 4 mg/dL)

What threshold of CRP elevation is associated with an odds ratio of 3.0 for kidney scarring?

Polymorphonuclear (PMN) cell count > 60%

What PMN cell percentage threshold carries an odds ratio of 1.9 for kidney scar formation?

Temperature ≥ 39°C (102.2°F)

What fever threshold carries an odds ratio of 2.3 for predicting kidney scar development?

UTIs caused by non-E. coli organisms

Which microbiological factor carries an odds ratio of 2.2 for kidney scarring after a first UTI?

Presence of leukocytes in urinalysis with a negative standard urine culture

What defines sterile pyuria?

Partially treated bacterial UTI, viral infections, urolithiasis, renal tuberculosis, renal abscess, urinary obstruction, and STI-related urethritis

What infectious and structural conditions can cause sterile pyuria in children?

Appendicitis, Crohn's disease, and Kawasaki disease

What inflammatory conditions near the ureter or bladder cause sterile pyuria?

COVID-19 MIS-C, schistosomiasis, neoplasms, renal transplant rejection, and interstitial nephritis

What systemic, neoplastic, and renal parenchymal disorders cause sterile pyuria?

Eosinophils

Which specific leukocyte type is present in urine in interstitial nephritis causing sterile pyuria?

Prompt plating or immediate refrigeration

What are the two recommended methods for storing a urine specimen prior to culture?

Overgrowth of minor bacterial contaminants, rendering the urine sample invalid

What occurs if an un-refrigerated urine sample sits at room temperature for greater than 60 minutes?

Children presenting with afebrile cystitis

In which pediatric UTI population are imaging studies generally considered unnecessary?

Renal-bladder sonogram plus a Voiding Cystourethrogram (VCUG)

Which imaging combination represents the "bottom-up" diagnostic approach for evaluating febrile UTIs?