infectious heart disease Flashcards

1
Q

Infectious endocarditis

A

Uniformly fatal if untreated
Predisposing factors: vlavulat heart disease (congenitial defects rheumatic disease
Prosthetic valves damage
IV drug use

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2
Q

Properties of successful IE pathogens

A

able to survive antimicrobial components of Serum
Able to adhere to endocardium

Dextran (exopolysaccharide)- viridans streptococci
Adhesins (surface proteins) that mediate attachment to platelets and fibrin–viridans streptococci
Fibrinogen-binding adhesins- S aureus

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3
Q

Most common etiologic agents

A

NORMAL MICROBIOTA
Staphylococcus aureus- colonizer of anterior nares, manifests as acute IE often with complications

Coagulase-negative Staphylococci (S epidermdis) colonizes of skin, prostheic valve endocarditis

Viridans streptococci (S sanguis, S mutans, S mitis) (oral cavity colonizer, S gallolyticus bovis --colonic lesions
Nutritionally variant strep

Rare agents: HACEK (haemophilus, actinobacillus, cardiobacterium, eikenella, kingella)- gram neg bacteria
Brucella, coxiella burnetti

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4
Q

Vegitation

A

Heterogenous matrix of deposited bacteria, platelets, fibrin, matrix ligands, protection from immune cells, bacteria can achieve high densities (limitations on nutrient exchange high cell density-bacteria are not growing rapidly), embolic phenomena

Implications for antibiotic therapy: bactericidal activity, parental admin for sustained activity, prolonged therapy required

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5
Q

2 requirements for ineffective endocarditis

A

A bug that sticks: majority of infections related to Staphylococcus aureus (bacteria which is very capable of attaching to and colonizing abnormal valve tissue)

Something to stick to: Abnormal heart valves or prosthetic device (suitible site for bacterial attachement and colonization)

Fatal if left untreated- evn with treatment mortality 20%, one year mortality 40%

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6
Q

Bugs that cause IE

A

Staphylococci and streptococci account for 80 percent of IE cases: Staph aureus can cause endocarditis in normal heart valves, Staph epidermidis in prosthesis, Viridans in oral health
HACEK group-
IV drugs: staph aureus, pseudomonas, candida
Culture neg: Coxiella, bartonella, brucella

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7
Q

Risk factors IE

A

common denominators: abnormal heart valves and risk of bacteremia (prosthetic valves, CIEDs, mitral valve prolapse, rheumatic heart disease, complex congenital, mitral regurgitation, aortic stenosis,

Aberrant flow results in platelet-fibrin thrombus on injured endothelium

Bacteria enter bloodstream through skin or mucosal surfaces and adhere to thrombus

Once inside growing thrombus, bacteria resistant to host defenses

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8
Q

Clinical presentation of IE

A

Acute or subacute onset, fever, heart murmur, chills, sweats, anorexia, malaise, weight loss, noncardiac manifestations,

Noncardiac manifestation- embolic events, splenomegaly, clubbing, petechiae, splinter hemorrhage, oslers nodes (ouch ouch oslers), janeway lesions, roths spots

Anemia, leukocytosis, microscopic heaturia, elevated ESR and CRP

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9
Q

Duke criteria

A

Major: Typical organism from 2 separate blood cultures, organism from persistently positive blood cultures, positive for serology (C, burnetti)

Evident of endocardial involvement (new valvular regurgitation, positive echocardiogram)

Minor: predisposition, fevre, vascular phenomena, immunologic phenomenoa,

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10
Q

Therapy for native valve endocarditis (6 wks)

A

Organisms are inaccessible to host defenses, metabolically inactive, must kill every bacterium in vegitation

Therapy must be bactericidal, prolonged weeks,

Oxacillin sensitive (staph aureus or CoNS), MSSA- no penicillin allergy or intolerance, IV nafcillin or cefazolin (if allergic vanco or dapto)

Oxacillin resistant MRSA IV vanco or daptomycin

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11
Q

Prosthetic valve endocarditis therapy

A

Oxacillin sensitive: MSSA: IV nafcillin or oxacillin for 6 weeks with IV Rifampin for 6 weeks, IV gentamicin for 2 weeks

Oxacillin resistant MRSA: IV vancomycin for 6 weeks with IV rifampin 6 weeks, IV gentamicin for 2 weeks

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12
Q

Viridans or enterococcus

A

Viridans: Penicillin susceptible (MIC

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13
Q

HACEK endocarditis treatment

A

Ceftriaxone 4-6 wks or ciprofloxacin 4-6 wks

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