Urinary Tract Infection in Children

Co. StephanieJanuary 23. 2014

Prevalence• Occurs in 1-3% of girls, 1% of boys – Girls: usually occurs by 5 yrs of age

• peaks during infancy and toilet training

– Boys: common during the 1st year of life• more common in uncircumcised boys

• Male:Female ratio1st year of life 2.8 : 5.4

>1-2 years 1 : 10

Etiology• Main agent: colonic bacteria – 75-90%: caused by E. coli, • followed by Klebsiella spp and Proteus spp• Proteus spp: common for boys >1 yr of age

– Other pathogens: Staph saprophytius and enteroccocus,

– Viral causes: adenovirus and other viral infections

Risk FactorsFemale Wiping from back to

front (girls) Anatomic abnormality (labial adhesion)

Uncircumcised male Bubble bath Neuropathic bladder Toilet Training Tight

clothing/underwearSexual activity

Voiding dysfunction Pinworm infestation PregnancyObstructive uropathy Constipation Vesicoureteral reflux*Urethral instrumentation

Bacteria with P. fimbriae *increase risk for PYELONEPHRITIS

CLASSIFICATIONS

① Pyelonephritis• Most common serious bacterial infection in infants <24 mo of age who

have fever WITHOUT an obvious focus

② Cystitis

③ Asymptomatic Bacteriuria

PYELONEPHRITIS

a. Abdominal, back, or flank pain

b. Fever

c. Malaise

d. Nausea and vomiting

e. Occasional diarrhea

Indicative of a bacterial infection of the UPPER URINARY TRACT

ACUTE PYELONEPHRITIS: WITH renal parenchymal involvement • can result to pyelonephritic scarring

PYELITIS: NO parenchymal involvement

ACUTE LOBAR NEPHRITIS: renal mass caused by acute focal infection without liquefaction; can be an early stage of renal abscess development

XANTHOGRANULOMATOUS PYELONEPHRITIS: Rare infection characterized by granulomatous inflammation with giant cells & foamy histiocytes

CYSTITIS

a. Dysuria

b. Frequency

c. Urgency

d. Suprapubic pain

e. Incontinence

f. Malodorous urine

• NO:✘ Fever

✘Renal Injury Acute Hemorrhagic Cystitis: often caused by E. coli and Adenovirus types 11 and 21• Adenovirus cystitis: more common in boys; self-limiting infection

Eosinophillic cystitis: rare form occasionally found in children • Usual symptoms: Hematuria, ureteral dilation with occasional

hydronephrosis, and filling defects in the bladder • May have been exposed to an allergen

Interstitial cystitis: IRRITATIVE voiding symptoms such as urgency, frequency, and dysuria, and bladder/pelvic pain • Relieved by voiding with a negative urine culture• Most likely affects adolescent girls; idiopathic

Indicative of BLADDER INVOLVEMENT

ASYMPTOMATIC BACTERIURIA• Positive urine culture WITHOUT any manifestations of infection

• Most common in girls – <1% in pre-school and school-age

– Rare in boys

• Benign condition: does not cause renal injury EXCEPT in pregnant women

Pathogenesis: Ascending infection

Bacteria arise from fecal flora

Colonize the

perineum

Pass the urethra

Enter the

bladder CYSTITIS

Pathogenesis: Ascending infection

CYSTITISInfection

ascends to the kidney

ACUTE PYELONEPHRITIS

Pathogenesis: ACUTE PYELONEPHRITIS• NORMAL kidney: Simple and compound papillae have an

antireflux mechanism that prevents urine in the renal pelvis from entering the collecting tubules– Some compound papillae (esp. upper and lower poles) allow for

INTRARENAL reflux

• Infected urine: stimulate inflammatory & immunologic response

Diagnosis• A urine culture is necessary for

confirmation and appropriate therapy (Nelsons 19th ed)

• Urine sampling: – Toilet-trained: midstream catch

– Uncircumcised boys: retract prepuce first

– Not toilet trained: catheterized urine sample

• A positive culture can result from skin contamination

Pyuria• Definition: positive leukocytes

• Infection CAN occur in the absence of pyuria

• Suggestive of infection; More confirmatory than diagnostic

• Pyuria can be present without UTI

Sterile pyuria• Definition: positive leukocytes, negative culture

• Nitrites and leukocyte are usually positive in infected urine

• Microscopic hematuria is common but alone does not suggest UTI

Partially treated bacterial UTI’s Urethritis due to STI

Viral infections Inflammation near the ureter/bladder (appendicitis, Crohn’s disease)

Renal tuberculosis Interstitial nephritis (eosinophils)

Renal abscess UTI due to urinary obstruction

Asymptomatic child + normal urinalysis = Unlikely that there is UTI

Symptomatic child + negative urinalysis result = UTI is still possible

Urine culture

• POSITIVE RESULT: >100,000 colonies of a single pathogen 10,000 colonies AND Symptomatic child

• Presumed UTI: Bag sample Positive urinalysis + Symptomatic patient + >100,000 colonies of a

single organism Confirm with a catheterized sample if any of the criteria is not met

Other tests• CBC: leukocytosis, neutrophilia

• Serum Erythrocyte sedimentation rate: elevated

• C-reactive protein: elevated

Imaging• Goals:

Determine anatomic abnormalities that predispose to infection Determine whether there is active renal involvement Assess renal function risk

Imaging: DMSA renal scan• Dimercaptosuccinic acid

(DMSA) renal scan

• Involved areas are photopenic showing enlarged kidneys – Approx. 50% with febrile UTI

will have a positive DMSA scan

– 50% of those with positive DMSA scans will develop renal scarring

Imaging: Voiding cystourethrogram Done for those with evidence

of acute pyelonephritis or renal scarring on DMSA scan

• Can help identify reflux

• Can be delayed 2-6 wks to allow for bladder inflammation to resolve

TreatmentAcute cystitis: should be properly treated to avoid

progression to pyelonephritisSevere symptoms: presumptive treatment is started

pending results of urine cultureMild symptoms/Doubtful diagnosis: delay treatment

until culture results

Treatment regimen: Acute Cystitis

• If treatment is initiated before culture results: a. Trimethoprim-sulfamethoxazole (TMP-SMX) or

trimethoprim (for 3-5 days): effective against most strains of E. coli

b. Nitrofurantoin (5-7mg/kg/24 hr in 3-4 divided doses): effective against Klebsiella and Enterobacter

c. Amoxicillin (50mg/kg/24hr): effective but no clear advantage

Treatment regimen: Acute Pyelonephritis

• 10-14 day course of broad-spectrum antibiotics capable of reaching significant tissue levels is preferred

• Dehydration, vomiting, poor oral intake: signs to admit a child for IV rehydration and IV antibiotic therapy

• Ceftriaxone (50/75 mg/kg/24hr – not exceed 2g) or Cefotaxime (100mg/kg/24hr) or Ampicillin (100mg/kg/24hr) with an Aminoglycoside (ex Gentamicin 3-5mg/kg/24hr in 1-3 divided doses)

Treatment

• Ciprofloxacin is an alternative agent for resistant microorganisms in patients >17 yr or short course treatment for young children

• Clinical use of fluoroquinolones in children should be restricted because of potential cartilage damage

Treatment: Recurrent UTI

a. Identify predisposing factors

b. Prophylaxis against reinfection: controversial • TMP-SMX, Trimethoprim, Nitrofuratoin at 30% of the normal dose

c. Probiotic therapy: replaces pathologic urogenital flora*

d. Cranberry juice: prevents bacterial adhesion and biofilm formation*

Complications• Renal scarring: Highest risk in

children <2 years old

• Renal insufficiency or end-stage renal disease in children

• Arterial hypertension

Thank you.