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20 Cards in this Set
- Front
- Back
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Definition
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Infective endocarditis is an infection of a cardiac valve or the endocardium caused by bacteria, fungi, or chlamydia. Pathological findings include the presence of often friable, valvular vegetations containing bacteria, fibrin, platelets and inflammatory cells. There is often valvular destruction with local intracardiac complications. A chunk of the friable vegetation may break off and embolize. Bacteria may also seed other tissues causing metastatic infections.
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Incidence?
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1.7-6.2 per 100,000,
there has been a change in the underlying valvular disease with rheumatic valvular disease being less common and atherosclersosis and mitral valve prolapse being more common. |
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Graph of organism and percent of cases
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Organisms
Staphylococcus aureus 31% Coagulase negative staphylococci 10.5 Viridans group streptococci18.0 Streptococcus bovis 6.5 Other streptococci 5.1 Enterococcus spp.10.6 Gram negative bacilli Fungi 3.8 Polymicrobial Culture negatives 8.1 |
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What is primary pathogen for subacute endocarditis?
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Veridans Streptococci
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What endocarditis is linked with colonic carcinoma?
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Streptococcus Bovis
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What accounts for 80% of acute cases? and is the primary pathogen for IV drug users?
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Staph aureus
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What is most common in cases with a prosthetic valve?
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Coagulase negative staph
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What are the pre-disposing factors?
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antecedent dental, genitourinary or gastrointestinal procedures, IV drug use, invasive medical procedures such as IV lines of hemodialysis, and surgical replacement of cardiac valves
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What is first step of getting endocarditis?
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Transient bacteremia
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Second step?
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Bacterial seeding on cardiac valve, in subacute disease bacteria seed sites of previous micro or macroscopic damage
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Vegetation formation
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Once bacteria have colonized the valvular surface a vegetation forms. This consists of bacteria encased in a meshwork of platelets and fibrin. The vegetation serves as a barrier to host defenses. It is not vascularized, has few mononuclear or PMNs and is therefore not easily sterilized by host factors or antimicrobials.
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Pathology
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The gross appearance of vegetations is variable. There may be single or multiple lesions. Destruction of the underlying valve is often present. There is often greater necrosis and friability of the lesions associated with acute IE. Adjoining structures e.g. chordae, myocardial abscesses may also be involved.
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Clinical manifestations
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heart murmurs, hypergammablobulinemia, splinter hemorrhages, bland or septic embolization, sustained bacteremia, petechiae, osier nodes (a necrotizing vasculitis of the glomus body) and Janeway lesions. Central nervous system findings include emboli seen in > 1/3 of all cases. Rupture of infected cerebral aneurysms (mycotic) can also occur.
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Lab findings
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Blood Culture
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Prothetic valve endocarditis, Early and Late
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Early is < 60 days after surgery, usually coagulase negative staph and mortality is high 40%-80%.
Late >60 days, with organisms related to dental genitourinary r skin sources with low virulence streptococci most common. |
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Duke Criteria?
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Definite: 2 major 1 minor, or 1 major 3 minor, or 5 minor.
possible= 1 major 1 minor, or 3 minor major includes positive blood culture echocardiogram, new murmur. |
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High risk of disease?
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Prosthetic valve
complex congenital heart disease previous endocarditis cardiac translations with valvulopathy |
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Moderate risk?
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Acquired valvular dysfunction, mitral valve prolapse with regurgitation (associated with IV drug use)
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negligible risk?
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Mitral valve prolapse without regurgitation
Rheumatic fever without valvular dysfunction |
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Prophylaxis?
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Prophylaxis recommended in high risk patients for dental procedures that involve manipulation of tissue, procedures that involve respiratory tract, infected skin or skin structures.
NOT recommended for gastrointestinal of genitourinary procedures. |
