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Cardio CP2 > 10 Infectious Heart disease > Flashcards

10 Infectious Heart disease Flashcards

1
Q

What are the two “requirements” for infectioius endocarditis?

A
  • “Something that sticks”
    • staph and strep= 80% of cases
  • “Something to stick to”
    • abnormal heart valves or prosthetic device
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2
Q

What are some common bacteria in IE?

A
  • staph aureus (even sometimes with normal valves)
  • staph epidermidis (esp with prosthetic valves/devices)
  • viridans group strep (VGS)
  • enterococcus (esp in elderly or pts with GU disease)
  • HACEK group (Gram negatives: Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella)
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3
Q

What pathogens should be suspected in an IV drug user IE?

A
  • staph aureus
  • pseudomonas
  • candida albicans
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4
Q

What are some causes of culture negative endocarditis?

A
  • coxiella burnetti
  • bartonella
  • brucella
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5
Q

What is the progression of IE?

A
  • abnormal heart valves -> aberrant flow -> platelet-fibrin thrombus on injured endothelium
  • risk for bacteremia -> bacteria enter blood stream (through skin or mucosal surface) -> adhere to thrombus
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6
Q

What are some common clinical presentations of IE?

A
  • fever (chills, sweats)
  • heart murmur (new/worse= especially concerning)
  • anorexia, malaise
  • noncardiac manifestation (e.g. emboli, splenomegaly, clubbing, petechiae, roth spot retinal hemorrhages)
  • lab abnormalities
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7
Q

What are osler’s nodes? Janeway lesions?

A
  • Oslers
    • Painful Purple Pea sized bumps on Pulp of fingers
    • Inflammatory/immune complexes
  • Janeway
    • Similar to Osler’s but painless
    • Due to septic emboli
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8
Q

What are some common lab abnormalities of IE?

A
  • anemia
  • leukocytosis
  • microscopic hematuria
  • elevated ESR/CRP (inflammatory markers)
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9
Q

Why does it matter how long a patient has had a prosthetic valve/device?

A

Always consider staph aureus/epidermidis but…

  • less than 1 year consider
    • gram negatives (nosicomial infection)
  • more than 1 year consider
    • viridans group strep
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10
Q

What tests should be run if IE is suspected?

A
  • at least 3 sets of blood cultures (from different sites)
  • ECG (TEE>TTE)
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11
Q

What antibiotics should be given for MSSA infection of a native valve? What if there’s a penicillin allergy?

A

6 weeks of IV…

  • Nafcillin and/or cefazolin
  • allergy= vancomycin and/or daptomycin
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12
Q

What antibiotics should be given for MRSA infection of a native valve?

A

vancomycin and/or daptomycin

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13
Q

What antibiotics should be given for an MSSA infection of a prosthetic valve?

A
  • IV nafcillin/oxacillin/cefazolin for 6 weeks
  • IV/PO rifampin for 6 weeks (biofilms!)
  • IV gentamicin for 2 weeks

**combo therapy when prosthetic valve involved

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14
Q

What antibiotics should be given for an MRSA infection of a prosthetic valve?

A
  • IV vancomycin for 6 weeks
  • IV/PO rifampin for 6 weeks (biofilms!)
  • IV gentamicin for 2 weeks

**combo therapy when prosthetic valve involved

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15
Q

What antibiotics should be given for a VGS IE?

A
  • penicillin/ceftriaxone 4-6 weeks (possibly add gentamicin as needed for 2 weeks)
  • vancomycin 4-6 weeks
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16
Q

What antibiotics should be given for enterococci IE?

A
  • penicillin/ampicillin 6 weeks
  • gentamicin or ceftriaxone 2-6 weeks
    • or vancomycin with gentamicin 6 weeks
17
Q

What antibiotics should be given for HACEK IE?

A

ceftriaxone or ciprofloxacin 4-6 weeks

18
Q

When is endocarditis prophylaxis indicated?

A

For manipulation of gingiva/periapical teeth or perforation of oral mucosa in patients with…

  • prosthetic valves
  • previous IE
  • cardiac transplant with valvulopathy
  • congenital heart disease
19
Q

What antibiotics are used for IE prophylaxis?

A

Oral: Amoxicillin and clindamycin

IV: Ampicillin and ceftriaxone

**single dose 30-60 min before procedure

20
Q

What are some reasons for “culture negative” endocarditis?

A
  • antibiotic treatment already started
  • nutritionally variant strep (needs supplemental media)
    • abiotrophia, granulicatella
  • coxiella burnetti (Q fever; rural living/birthing of sheep)
  • bartonella (“cat scratch” fever)
  • brucella (unpasturized milk/cheese)
  • tropheryma whipplei
21
Q

What is the natural bacteria found in the anterior nares? (can cause IE)

A

Staph aureus

22
Q

What is the natural bacteria found on the skin? (can cause IE)

A

Staph epidermidis (coag neg)

23
Q

What is the natural bacteria found in the oral cavity? (can cause IE)

A

viridans strep (sanguis, mutans, mitis)

24
Q

What is the natural bacteria found in the GI tract? (can cause IE)

A

enterococci (faecalis, faecium)

25
Q

What properties allow a pathogen to adhere to the endocardium?

A
  • dextran (exoplysaccharide); viridans strep
  • adhesins (FinA, GspB, PblA, PblB) meciate attachment to platelets and fibrin; viridans strep
  • fibrinogen-binding adhesins (ClfA, coagulase); S aureus
26
Q

Describe a vegetation

A
  • heterogeneous matrix of deposited bacteria, platelets, fibrin, and other matrix ligands
  • protection from immune cells allows bacteria to grow to high densities
    • limits nutrient exchange -> bacteria not growing rapidly -> limits antibiotic effectiveness
  • can embolize
27
Q

What are the major classes of antibiotics given for IE?

A
  • cell wall agents
    • beta lactams; cefazolin, ceftriaxone, penicillin, nafcillin, ampicillin
    • vancomycin
    • daptomycin
  • protein synthesis inhibitors
    • gentamicin
  • RNA synthesis inhibitors
    • rifampicin
28
Q

What are PBPs?

A

Penicillin binding proteins; responsible for crosslinking alanines of the peptidoglycan

**inhibited by beta lactam antibiotics (penicillins, cephalosporins, carbapenem, monobactam)

29
Q

What is the MOA of vancomycin?

A
  • binds D-Ala-D-Ala
  • “hides” crosslinking msubstrate from PBPs

**not effective for gram negatives; too big to cross surface

30
Q

What is the MOA of daptomycin?

A
  • binds and disrupts the cytoplasmic membrane, leading to bacteria death
  • bactericidal, narrow spectrum (gram positives), good for antibiotic resistant bacteria
31
Q

What is the MOA of rifampin?

A
  • binds the beta subunit of bacterial RNA polymerase, inhibiting it/preventing RNA synthesis
  • high risk of rapid resistance selection (not generally used for monotherapy)
32
Q

What is the MOA of gentamicin?

A
  • an aminoglycoside; bind irreversibly to 30S ribosomal subunit, stopping the initiation phase of protein synthesis (misreading -> premature release or ribosome from mRNA)
  • does not penetrate gram positives well (not used in monotherapy)

**use for enterococci

Cardio CP2 (8 decks)

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