[04.14] PED - UTI and Congenital Anomalies of the Kidney and Urinary Tract.pdf

5% to 14%

What percentage of pediatric emergency room visits are accounted for by urinary tract infections?

Under 1 year of age

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

8%

What is the prevalence of afebrile symptomatic UTI in children over 1 year of age?

7%

What is the prevalence of febrile infants presenting with a UTI?

First year of life

During what period of life do most urinary tract infections occur in boys?

Uncircumcised state and shorter urethral anatomy during infancy

What anatomical factors make uncircumcised infant males more vulnerable to UTIs?

20% risk in uncircumcised males versus 2.4% risk in circumcised males

What is the risk of UTI in uncircumcised febrile male infants under 3 months compared to circumcised males?

Infancy, toilet training, and onset of sexual activity

What three developmental peaks mark an increased prevalence of UTI in girls?

UTI is never considered normal in either sex

What is the clinical rule regarding whether a UTI can be considered normal in any child?

Fever, vomiting, lethargy, and irritability

What are the four most common symptoms of UTI in infants younger than 3 months?

Poor feeding and failure to thrive

What are the two moderate-frequency symptoms of UTI in infants younger than 3 months?

Abdominal pain, jaundice, hematuria, and offensive urine

What are the four least common symptoms of UTI in infants younger than 3 months?

Fever

What is the single most common symptom of UTI in preverbal infants and children aged 3 months or older?

Abdominal pain, loin tenderness, vomiting, and poor feeding

What are the four moderate-frequency symptoms of UTI in preverbal children aged 3 months or older?

Lethargy, irritability, hematuria, offensive urine, and failure to thrive

What are the five least common symptoms of UTI in preverbal children aged 3 months or older?

Urinary frequency and dysuria

What are the two most common symptoms of UTI in verbal children?

Dysfunctional voiding, changes to continence, abdominal pain, and loin tenderness

What are the four moderate-frequency symptoms of UTI in verbal children?

Fever, malaise, vomiting, hematuria, offensive urine, and cloudy urine

What are the six least common symptoms of UTI in verbal children?

Temperature > 39°C

What temperature threshold defines a fever without an obvious source that warrants UTI evaluation in infants?

24 hours in males and 48 hours in females

What duration of unexplained fever triggers a UTI evaluation in infant males versus infant females?

Acute lobar nephronia

What localized renal parenchymal mass caused by acute focal infection represents an early stage of renal abscess?

Older children

In which age group is acute lobar nephronia more commonly observed?

Unilateral and right-sided

Which side is most commonly affected in pediatric renal abscesses?

Hematogenous spread of Staphylococcus aureus

What mechanism and pathogen cause renal abscesses?

Staphylococcus aureus and Escherichia coli

What two pathogens are most frequently implicated in perinephric abscesses?

Diffuse involvement throughout the renal capsule without being walled off

What anatomical feature distinguishes a perinephric abscess from a renal abscess?

The abscess may not communicate with the collecting system

Why can a urinalysis remain completely normal in a patient with a perinephric abscess?

Xanthogranulomatous pyelonephritis

What granulomatous inflammation featuring giant cells and foamy histiocytes manifests as a renal mass?

Cystitis

Which localized infection involves only the urinary bladder and presents with dysuria, urgency, frequency, suprapubic pain, and malodorous urine?

Cystitis does not cause high fever and does not cause renal injury

How does cystitis differ from pyelonephritis regarding fever and renal parenchyma damage?

Escherichia coli and Adenovirus types 11 and 12

What bacterial organism and viral serotypes cause acute hemorrhagic cystitis?

Urinary tract infection

What is the single most common cause of hematuria in children?

Adenovirus-induced hemorrhagic cystitis is self-limiting and does not require antibiotic therapy

Why should viral acute hemorrhagic cystitis not be treated with antibiotics?

1.4% to 1.9%

What is the prevalence of asymptomatic bacteriuria in childhood?

Presence of bacteria in urine without active infection or symptoms

What defines asymptomatic bacteriuria?

Ascending infection from fecal flora colonizing the perineum

What is the primary route of entry for pathogens causing pediatric pyelonephritis?

Escherichia coli

What is the predominant uropathogen causing ascending UTIs in children?

Children under 2 years of age

Which age group carries the greatest risk of renal parenchymal injury and scarring from acute pyelonephritis?

Voluntary urine retention causes uninhibited bladder contractions, high intravesical pressure, turbulent urine flow, and incomplete emptying

How does toilet training increase the risk of UTI in young children?

7 years of age

By what age are children usually fully toilet trained?

Incomplete bladder emptying and detrusor-sphincter dyssynergy requiring intermittent catheterization

Why do children with neuropathic bladders frequently contract UTIs with antibiotic-resistant organisms?

Rectal distention from hard stool compresses the bladder neck, leading to incomplete bladder emptying and dysfunction

How does constipation with fecal impaction contribute to pediatric UTIs?

Bristol type 1 (separate hard lumps) and Bristol type 2 (lumpy sausage-shaped stool)

Which Bristol stool types indicate constipation in school-age children?

Clean catch method

Which urine collection method is recommended for non-toilet-trained children under 2 years of age?

Rubbing the suprapubic area gently with a cold or damp cotton ball or gauze

How is voiding stimulation performed during a clean catch collection in an infant?

The first few milliliters contain high epithelial cell counts from external genital urethral flora

Why are the first few milliliters of a voided urine sample discarded in older children?

99% Negative Predictive Value

What is the clinical value of a negative urine bag (wee bag) culture or urinalysis?

High risk of contamination from perineal skin and fecal flora

Why can a positive culture from a urine bag never be used to definitively diagnose a UTI?

Nitrites and Leukocyte Esterase

What two primary dipstick parameters screen for a urinary tract infection?

Enterococcus infection or increased urinary frequency

What two factors cause a false-negative nitrite test on a urine dipstick?

Enterococcus lacks the nitrate reductase enzyme required to convert nitrates to nitrites

Why do Enterococcus infections yield negative nitrite dipstick results?

Frequent voiding leaves insufficient bladder dwell time for bacteria to convert nitrates to nitrites

Why does urinary frequency cause false-negative nitrite results?

83% sensitivity and 78% specificity

What are the sensitivity and specificity of the leukocyte esterase test alone?

53% sensitivity and 98% specificity

What are the sensitivity and specificity of the nitrite test alone?

93% sensitivity and 72% specificity

What are the sensitivity and specificity when either leukocyte esterase or nitrite is positive?

99.8% sensitivity and 70% specificity

What are the sensitivity and specificity when leukocyte esterase, nitrite, or microscopy is positive?

WBC >= 5/hpf in centrifuged urine or WBC >= 10/hpf in uncentrifuged urine

What numerical threshold defines pyuria on urinalysis?

High urinary WBC count with a negative bacterial culture

What defines sterile pyuria?

Partially treated UTI, viral infections, urolithiasis, renal tuberculosis, and renal abscess

What are five causes of sterile pyuria in children?

Overgrowth of minor contaminating skin flora

What happens to an unpreserved urine sample left at room temperature for longer than 60 minutes?

Refrigeration

What is the recommended storage method for urine samples awaiting culture?

Growth of >= 50,000 CFU/mL of a single uropathogen in a suprapubic aspirate or urethral catheter sample with pyuria or bacteriuria

What is the gold standard culture threshold for diagnosing UTI in a symptomatic child via catheter or SPA?

Growth of >= 100,000 CFU/mL (or >= 50,000 CFU/mL in symptomatic children) of a single pathogen

What is the culture cutoff for diagnosing a UTI from a clean-catch or midstream sample?

To prevent delayed treatment and reduce the risk of permanent renal scarring

Why do recent guidelines treat >= 50,000 CFU/mL in clean-catch urine as a UTI in symptomatic children?

Failure to respond within 48 hours of appropriate antibiotics, poor urine flow, abdominal or flank mass, non-E. coli pathogen, urosepsis, and elevated creatinine

What are six atypical clinical features in pediatric UTI that mandate diagnostic renal imaging?

Kidney ultrasound combined with Voiding Cystourethrogram (VCUG)

What modalities comprise the "bottom-up" imaging approach for pediatric UTI?

Vesicoureteral reflux (VUR), bladder-bowel dysfunction, and paraureteral diverticulum

What structural and functional abnormalities are identified by the bottom-up imaging approach?

DMSA renal scan

What modality represents the "top-down" imaging approach?

A positive DMSA scan indicates acute pyelonephritis, prompting a subsequent VCUG

What is the procedural sequence in the top-down imaging approach?

90%

What percentage of children with a positive DMSA scan exhibit dilating vesicoureteral reflux?

KUB Ultrasound

What non-invasive, accessible imaging modality serves as the initial test to evaluate kidney anatomy, obstruction, or renal abscess?

Within 12 to 36 hours of acute presentation

When should an acute KUB ultrasound be performed if a child with a febrile UTI fails to improve on antibiotics?

Severe hydronephrosis, renal scarring, findings suggestive of reflux/obstruction, recurrent febrile UTIs, or atypical clinical features

What are five indications for performing a Voiding Cystourethrogram (VCUG)?

Dimercaptosuccinic acid (DMSA) renal scan

Which radionuclide scan is sensitive and specific for detecting acute pyelonephritis?

DMSA cannot reliably distinguish acute pyelonephritic focal lesions from chronic permanent renal scarring

What is a major diagnostic limitation of the DMSA renal scan?

50%

What percentage of children with an abnormal acute DMSA scan go on to develop permanent renal scarring?

Leukocytosis and neutrophilia

What peripheral blood count findings support the diagnosis of acute pyelonephritis?

Procalcitonin

Which serum biomarker is a strong, early, sensitive, and specific predictor of acute pyelonephritis?

Relief of symptoms, eradication of infection, prevention of urosepsis, and prevention of recurrence and long-term renal damage

What are the four primary goals of pediatric UTI treatment?

Prompt administration of targeted antibiotics without delay after obtaining a proper urine sample

What is the primary intervention to prevent acute renal parenchymal injury during a UTI?

Age less than 2 months, immunocompromise, inability to tolerate oral medications, and presence of atypical features

What are four indications for administering intravenous antibiotics in pediatric UTI?

After the child has been clinically improved and afebrile for at least 24 hours

When can a hospitalized child with a febrile UTI be safely switched from IV to oral antibiotics?

30 to 50 mg/kg/day in 2 divided doses PO

What is the oral dosage of Co-Amoxiclav for acute cystitis?

5 to 7 mg/kg/day in 3 to 4 divided doses PO

What is the oral dosage of Nitrofurantoin for acute cystitis?

20 to 30 mg/kg/day in 2 divided doses PO

What is the oral dosage of Cefuroxime for acute cystitis?

100 mg/kg/day (Ampicillin component) in 4 divided doses IV

What is the IV dosage of Ampicillin-Sulbactam for acute cystitis?

Nitrofurantoin achieves high urinary concentration but has poor tissue penetration

Why is Nitrofurantoin indicated for afebrile lower cystitis but contraindicated in acute febrile pyelonephritis?

3 to 5 days

What is the total treatment duration for acute cystitis?

7 to 14 days

What is the total treatment duration for acute febrile UTI / pyelonephritis?

Front-to-back wiping after toilet use, avoiding bubble baths, maintaining hydration, routine voiding, and addressing constipation

What are five non-pharmacologic measures to prevent recurrent UTIs?

Breastfeeding

What nutritional practice in infancy is proven to protect against UTIs?

Neuropathic bladder, urinary stasis/obstruction, severe VUR, and urinary calculi

What four anatomical or functional conditions justify long-term antibiotic prophylaxis?

Antibiotic prophylaxis increases the risk of developing antibiotic-resistant bacterial infections

What is a major risk associated with continuous antibiotic prophylaxis in children?

Continuous antibiotic prophylaxis is not recommended after a first episode of pyelonephritis without structural abnormalities

What is the guideline recommendation regarding antibiotic prophylaxis after a first episode of pyelonephritis without structural defects?

Recurrent acute pyelonephritis and CAKUT

What childhood renal conditions significantly increase the risk of developing adult End-Stage Kidney Disease (ESKD)?

Congenital Anomalies of the Kidney and Urinary Tract

What does the acronym CAKUT stand for?

20% to 50%

What percentage of all prenatally detected birth defects are represented by CAKUT?

4 to 60 cases per 10,000 live births

What is the incidence of CAKUT per live births?

Intermediate mesoderm within the urogenital ridge

From which embryonic mesodermal layer does renal embryology originate during the 4th gestational week?

Nephrogenic cord

Which embryonic mesodermal structure gives rise to the primary urinary organs?