Flashcards in 04-23 Bacteremia & Endocarditis Deck (35):
Intermittent vs. Continuous Bacteremia
—intermittent is due to infx and obstruction (e.g. pylo, cholecystitis), undrained abscesses
—Continuous is due to an endovascular source (e.g. infectious endocarditis, infected grafts/shunts, infected arterial aneurysm
Sort these pathogens into normal flora (often contaminant) vs. likely pathogen.
—Gram neg bacilli
nl flora —Coag-neg staph (unless FB)
nl flora —Propionibacterium acnes
nl flora —Bacillus spp
nl flora —Strep viridans
pathogen—Strep pyogenes (GROUP A)
pathogen—Gram neg bacilli
—grown on just on one of the two or three cultures you drew.
—present without left-shift
—have no 1° infx or predisposing
infective vs. marantic endocarditis
infective is infection of valves or mural endocardium
marantic has sterile vegetations due to malig or CT dz
Acute vs. Subacute endocarditis
Acute: rapid progression, presents w/in 1 wk of sx onset
—abrupt onset (pt remembers start)
—due to INVASIVE pathogen (S. aureus, β-hemolytic strep, Pneumococcus)
—occurs on normal or abnl valves
—heart murmur ∆ing rapidly → CHF
—systemic sx: rigors & high fever
—More cutaneous and visceral emboli
Subacute: SBE sx may start weeks to months before presentation
—due to low-grade pathogens (Viridans strep, coag-neg staph)
—occurs on ABNORMAL valves
1. jet lesion (turbulent flow) or trauma (catheters, particles from IVDU) or chronic inflammation →
2. local thrombosis →
a. acts as nidus for infection
b. fibrin-plts blocks PMNs from bacteria
Predisposing factors to endocarditis in native valves besides IVDU, MVP, degen valve, rheumatic heart dz etc.
—poor dental hygiene
—sp. esp common in elderly?
Viridans streptococci are part of nl oral and colonic flora
—S. sanguis, S. bovis, S. mutans, S. mitis
—S. bovis common in elderly w/ chronic lesions, cancer
Microbe causing IE in older men?
enterococci in men with BPH or other persistent bladder outlet obstruction
—also generally common in nosocomial
Polymicrobial IE common in?
IVDU (putting needle in mouth, wiping it on something)
Top Causes of IE?
S. aureus now = Viridans Strep spp.
—Staph esp in IVDU and nosocomial
Group of non-classic organisms that can also causes IE
Other non-classic IE organisms
Bartonella spp. (cat-scrath, trench fever)
Q fever (Coxiella burnetii)
Most common non-culture finding in SBE?
anorexia, wt loss, malaise, night sweats
emoblic stigmata (petcchiae on skin, conjuctivae)
tender subQ nodules often in pulp of digits or thenar eminence; due to immune complex
linear, red at first then brown, lesions under the nails due to emboli
nontender erythematous, hemorrhagic, or pustular lesions, often on palms or soles
Acute abd pain, ileus, GI bleed
Kidney (micro hematuria, renal insuff)
IE in IVDUs
—S. aureus, Gm-negs (esp Pseudomonas), polymicrobial, Candida albicans
—Tricuspid valve often
–Present w/ high fever, cough, chills, malaise, pleuritic CP (septic pulmonary emboli = hallmark of R-sided IE)
True or false: mechanical valves have a higher rate of IE than bioprosthetic valves?
False, the two types have comparable rates of IE
Incidence of IE in prosthetic valve pts?
—Time correlation w/ source of infx?
1-3% w/in 1 year s/p inplant
—if w/in 2 mos, infx likely nosocomial
—if >12 mos s/p = "community acquired"
Duke Criteria for Dx of IE
—Typical orgs or 2 sep BCs or persistently (+) BCs
—Endocardial involve (regurg, echo proof)
—Predispos (IVDU, prev IE, valvulopathy)
—Immun phenom (RF, GN, Osler's nodes, Roth spots)
—Micro findings that don't meet MAJ CRIT
[Definitive if 2 MAR or 1 MAJ + 1 MINOR or 3 MINOR]
retinal hemorrhages with white or pale centers composed of coagulated fibrin
What IE Complications do you need to worry about?
—heart block (if in septum)
—stroke or brain abscess
—mycotic aneurysm rupture (Dx w/ CT or MRI)
—splenic, renal and/or hepatic emboli/abscesses
"an aneurysm arising from bacterial infection of the arterial wall. It can be a common complication of the hematogenous spread of bacterial infection" [wiki]
—classic mushroom shape (thus "mycotic")
Don't forget to get cultures BEFORE starting abx, okay?
Length of abx course?
at least 4 wks for native valve IE
at least 6 wks for prosthetic valve IE
Viridans strep tx w/ MIC ≤ 0.1ug/mL?
Pen G or ceftriaxone
Strep w/ MIC 0.1-0.5ug/mL
Pen + gent
enterococci or fastidious/resistant strep?
Pen + gent
Tx for biofilm forming bacteria?
Indications for surg?
—persistent bacteremia even w/ abx
—recurrent major emboli
—If infected with: Pseudomonas, fungi, highly resistant eneterococci (cause >50% of mortality from IE)