Campbell Pediatric GU Infections 2021 Flashcards
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Most common bacterial infection in children
UTIs are the most common bacterial infection in children, accounting for 7% of febrile infections in infants and 7.8% of febrile infections in children older than 24 months.
Significant clinical UTI
Catheterized: 50,000 CFU/mL
Clean-catch: 100,000 CFU/mL
Suprapubic aspiration: recovery of ANY organisms = UTI
AAP 2011 UTI:
UA should suggest infection + 50,000 CFU/mL through catheterization or suprapubic asp.
The first step in UTI pathogenesis
Adherence is considered the first step in UTI pathogenesis with special bacterial structures called adhesins mediating this process.
AKA: Pili or F antigens, and they are filamentous appendages that project from the bacterial cells.
K antigens
The capsules of most uropathic E. coli are composed of group II polysaccharides and are otherwise known as K antigens.
Encapsulated K bacterial strains are less well phagocytosed and also have anticomplementary activities, as compared with nonencapsulated strains, which leads to impaired bacterial clearance and complement activation
The only time UTIs are more prevalent in boys than in girls…
…is at an age younger than 1 year.
At all other ages, even among the elderly, UTIs are far more prevalent in females than in males.
*** 7% of girls and 2% of boys experience a UTI by the age of 6 years
Circumcision and pediatric UTI
Circumcision reduces the rate of UTI development in the first 6 months of life by almost 10-fold.
However, the question of whether circumcision actually prevents infections later in life continues to be debated in the literature.
Clinical studies show that women lacking ____ are at increased risk for vaginal colonization with E. coli.
Vaginal lactobacilli
Exposure to antibiotics, especially trimethoprim-sulfamethoxazole (TMP-SMX), may eradicate these presumably protective lactobacilli.
Recommended in all children aged 2 to 24 months after they have experienced their first febrile UTI.
Renal and bladder US (RBUS)
To detect possible anatomic abnormalities
TRUE or FALSE: Majority of children who have pyelonephritis have VUR.
FALSE.
Although VUR may be present in a child who has suffered a pyelonephritic infection, the majority of children who have suffered from pyelonephritis do not have VUR.
Bladder and bowel dysfunction
Dysfunctional elimination syndrome
- Infrequent voiding
- Incomplete bladder emptying
- Constipation
- Bladder overactivity
Commonly seen for evaluation of recurrent UTIs, daytime/nighttime urinary incontinence, urinary urgency, constipation, encopresis
Affects UTI and VUR
TRUE or FALSE: Treatment of bladder and bowel issues reduces recurrent UTIs and improves VUR resolution.
TRUE.
Treating children suffering from bladder overactivity with anticholinergics alone resulted in VUR resolution or improvement in 44% to 79% of children.
Treatment of children suffering from dysfunctional voiding with biofeedback resulted in VUR resolution in 55% to 63% of cases and improvement in VUR grade after 1 year of therapy
Neurogenic bladder treatment to prevent renal damage from abnormally high pressures causing renal damage and UTIs
Clean intermittent catheterizations facilitate the emptying of the bladders of patients with neurogenic bladder and lower chronic bladder distention and bladder pressure.
CIC and UTI
- 40% to 80% of individuals who intermittently catheterize develop chronic bacteriuria and/ or pyuria and most are asymptomatic
- ASB appears to lack morbidity most of the time
TRUE or FALSE: stopping prophylactic antibiotic in children with spina bifida is associated with reduced bacterial resistance
TRUE
TRUE or FALSE: Children with SB on CIC can undergo urodynamic studies without prophylactic antibiotics.
TRUE
TRUE or FALSE: Sterile, single-use, lubricated catheters reduce the risk of UTI in chronic intermittent catheterization
FALSE.
The use of sterile versus non-sterile, single versus multiuse, and lubricated versus nonlubricated catheters have shown no benefit in reducing the risk of UTI development
Most common nosocomial infection
Catheter-associated UTI (CAUTI) is the most common nosocomial infection, accounting for more than 1 million cases each year in US hospitals and nursing homes
- Increases with catheter duration
- Avoid morbidity with judicious use of catheters, remove when not necessary
Unresolved bacteriuria
Most commonly caused by inadequate bacterial therapy, which could be secondary to noncompliance, antibiotic malabsorption, suboptimal drug metabolism, and resistant uropathogens that were unresponsive to the attempted therapy
Bacterial persistence
After sterile urine has been documented after previous UTI therapy: the nidus causing the infection has NOT been eradicated.
Reinfection
The SAME pathogen is documented on urine cultures during subsequent UTI episodes, despite negative cultures after previous antibiotic treatment.
Asymptomatic bacteriuria
TWO consecutive urine specimens yielding positive cultures (>105 CFU/mL) of the same uropathogen
+
No infection symptoms
TRUE or FALSE: Children with ASB without VUR are at risk for recurrent UTI, renal damage, or impaired renal growth
FALSE.
Children in this age group who are without VUR and/or other genitourinary abnormalities do not require antibiotics to clear their bacteria because they do not appear to be at any risk for recurrent symptomatic infections, renal damage, or impaired renal growth.
Because anti-microbial therapy in these individuals is unlikely to prevent later asymptomatic or symptomatic bacteriuria, and untreated individuals appear to be at low risk of developing long-term sequelae related to the bacteriuria, routine antimicrobial therapy is NOT recommended.
Acute bacterial nephritis
Acute bacterial nephritis occurs as the INFLAMMATION from bacterial infection within the kidney begins to spread throughout the kidney in an increasingly suppurative process with heavier leukocytic infiltrate and focal areas of tissue necrosis.
Advanced generalized form: acute bacterial nephritis
Pyonephrosis
Purulent exudate from APN accumulates in a dilated renal collecting system.
CT findings: enlarged kidney with a grossly dilated collecting system containing higher- than-usual fluid attenuation.
Acute renal abscess early CT findings
- Well-defined area of low attenuation or decreased enhancement OR
- Striated, wedge-shaped zone of increased or decreased enhancement
AAP-recommended urine collection method for <2 yo
Either suprapubic aspiration (SPA) or IFC.
Compared with SPA, the catheterized urine has a sensitivity of 95% and a specificity of 99%.
Method of suprapubic aspiration (SPA)
The method of suprapubic aspiration involves prepping the skin and inserting a 22-gauge needle 1 to 2 cm above the pubic bone into the bladder and aspirating the urine into a sterile syringe.
_______ is a more robust predictor compared with CRP or WBC for selectively identifying children who had ACUTE PYELONEPHRITIS during the early stages of UTI as well as those with late scarring as identified by DMSA scanning.
Procalcitonin (>= 0.5 ng/mL)
71% sensitivity
72% specificity for APN
70% sensitivity and 50% specificity for late renal scarring
AAP Imaging Recommendations for UTI:
RBUS
VCUG if positive ultrasound
NO late DMSA scan
Top-down approach (TDA) imaging approach for UTI:
DMSA scan
VCUG if positive DMSA
NO RBUS
NICE guidelines imaging approach for UTI:
RBUS only if < 6 months or atypical UTI
It is also widely recognized that renal ultrasound includes a very low sensitivity for the detection of VUR, even with high grades of VUR.
Gold standard for detection and grading of VUR
Voiding cystourethrogram (VCUG)
Shows:
- Grade
- Presence of trabeculations
- Presence, size, and shape of diverticula
- Stool pattern suggestive of constipation
- Spinal defects: spina bifida occulta, tethered spinal cord
99mTc-Dimercaptosuccinic acid (DMSA) scan TIMING for APN and irreversible renal damage/scarring
APN: within first 10 days
Irreversible damage: not earlier than 6 months, may wait up to 1-2 years
UTI antibiotic treatment:
_____ of febrile UTI is a significant factor in LIMITING RENAL INVOLVEMENT and subsequent renal SCARRING.
EARLY antibiotic treatment
** incidence of acute scintigraphic renal lesions increased from 22% to 59% when the start of antibiotics went from 2 to 3 days from onset of symptoms
** rate of ultimate scar formation in this series also increased from 11% to 76.5% when the start of antibiotics went from 2 days to 6 days from the onset of symptoms
Antibiotic duration:
Afebrile acute cystitis
2-4 days
With less severe UTI, such as afebrile acute cystitis (lower UTI), a 2- to 4-day course has a reduced rate of recurrence compared with a single dose or a 1-day course and no significant difference compared with a 7- to 14-day course
Antibiotic duration:
Febrile UTI
7-14 days
Shorter courses have been proven inferior!
Antibiotic duration: Focal PN (acute lobar nephronia)
3 weeks
Antibiotic selection:
Neonates and young infants
Empiric:
Ampicillin + 3rd gen cephalosporin
Aminoglycosides if at risk for Pseudomonas
Coverage for: Enterococcus species
_______ has poor tissue penetration, should NOT be used in febrile UTI/APN, and has increased risk of hemolytic anemia in infants < 3 months
Nitrofurantoin
___ is contraindicated in premature infants and newborns < 6 weeks of age
TMP
___ should NOT be used as a first-line choice; reserve for suspected or proven resistant uropathogens such as Pseudomonoas
Fluoroquinolones
Who will benefit from prophylactic antibotics?
Higher risk for recurrent UTI: girls with dilating VUR (grade >= III)
TMP-SMX, TMP, nitrofurantoin, 1st gen. cephalosporins
Usually 1/4 the normal dose, given before bedtime ( to increase duration inside the bladder)
TRUE or FALSE: Cranberry juice reduces incidence of UTIs
FALSE.
At present, there does not appear to be enough evidence demonstrating conclusive benefit to warrant a recommendation for the routine use of cranberry juice or cranberry products in children for the prevention of UTIs.
TRUE or FALSE: Probiotics + antibiotics can reduce the incidence and recurrence of UTI.
TRUE.
Probiotics as monotherapy did NOT have a beneficial effect in reducing the incidence or recurrence of UTI.
Moderate efficacy (RR = 0.92; 95% CI 0.85–0.99; P = 0.02) was demonstrated when a probiotic was used as ADJUVANT therapy to antibiotics.
TRUE or FALSE: VUR + BBD = high risk for recurrent PN and UTI
TRUE.
Children with VUR and bowel and/or bladder dysfunction are at particularly high risk for developing recurrent pyelonephritis.
Recurrent UTI is estimated to occur in about 45% of these children as opposed to 15% without BBD.
Treatment of constipation has been shown to reduce recurrent UTIs significantly and to improve bladder function.
Most common cause of fungal UTIs
Candida species
Candida albicans is the most common species involved in these infections, followed by Torulopsis glabrata. It is important to recognize the infections caused by Torulopsis glabrata because these are commonly resistant to fluconazole.
Second most common cause of fungal UTIs, resistant to fluconazole
Torulopsis glabrata
Virus that causes acute hemorrhagic cystitis in children
Adenovirus-11
NEXT STEP:
Child with 38 C fever
< 29 days of age
ADMIT
CBC with differential urinalysis with urine culture Blood cultures
CSF studies with culture Start broad spectrum antibiotics
Observe for 48 hours or until etiology is identified
NEXT STEP:
Child with 38 C fever
> 29 days of age
Toxic appearance
ADMIT
CBC with differential urinalysis with urine culture Blood cultures
CSF studies with culture Start broad spectrum antibiotics
Observe for 48 hours or until etiology is identified
NEXT STEP:
Child with 38 C fever
Not toxic
29 - 90 days old
Option 1
CBC with differential urinalysis with urine culture Blood cultures
Stool cultures if indicated Chest x-ray if indicated CSF studies if antibiotics are indicated
Option 2
CBC with differential urinalysis with urine culture Discharge home with follow- up in 24 hours
NEXT STEP:
Child with 38 C fever
Not toxic
3-36 months
Observe only
NEXT STEP:
Child with 40 C fever
Not toxic
3-36 months
Option 1
Observe only Re-evaluate in 24-48 hours
Option 2
CBC with differential urinalysis with urine culture Discharge home with follow- up in 24 hours
NEXT STEP:
Child with 38 C fever
WBC < 15,000 AND ANC < 10,000 AND UA normal
Re-evaluate in 24 hours Follow-up culture results Consider Ceftriaxone 50 mg/kg IM
NEXT STEP:
Child with 38 C fever
WBC > 15,000 AND ANC > 10,000
Admit for observation
Obtain blood cultures Consider obtaining CSF studies
