Microbiology of Heart Disease Hersh DSA Flashcards Preview

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Flashcards in Microbiology of Heart Disease Hersh DSA Deck (53)
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31

acute endocarditis- clinical features

-fevers, chills, weakness, lassitude
-fever- most consistent sign!!
-murmurs- 90% of pts with left-sided IE

32

acute endocarditis- complications

-GN (glomerular ag-ab complex deposition)
-microthromboemboli
-erythematous or hemorrhagic nontender lesions on palms/soles (Janeway lesions)
-subcutaneous nodules in pulp of digits (Osler nodes)
-retinal hemorrhages in eyes (Roth spots)

33

4 major forms of vegetative endocarditis- morphology

-RHD- small, warty vegetations along closure lines of valve leaflets
-IE- large, irregular masses on valve cusps that extend onto chordae
-NBTE (nonbacterial thrombotic endocarditis)- small,bland vegetations attached at line of closure
-LSE (libman-sacks endocarditis)- medium vegetations on either/both sides of valve leaflets

34

Duke criteria- pathologic

-microorganisms by culture or histologic examination in a vegetation, embolus, or intracardiac abscess
-histologic confirmation of active endocarditis in vegetation or intracardiac abscess

35

Duke criteria- clinical- major

-2 blood cultures + for characteristic organism or persistently + for an unusual organism
-echocardiographic ID of valve-related or implant-related mass or abscess
-new valvular regurgitation

36

Duke criteria- clinical- minor

-predisposing heart lesion or IV drug use
-fever
-vascular lesions
-immunological phenomena (GN, osler nodes, roth spots)
-microbiologic evidence- culture positive for unusual organism
-echocardiographic findings- consistent with but not diagnostic of endocarditis- worsening/changing of preexistent murmur

37

Viridans Group Streptococci- 3 main types of infection

-dental infections (streptococci mutans)
-endocarditis (viridans streptococcus- slowly/subacute; staph aureus- fast/acute)
-abscesses (streptococcus intermedius)

38

Viridans Group Streptococci- virulence, treatment, diagnostics

-normal oral flora and GI tract
-extracellular dextran- helps bind to heart valves
-penicillin G
-gram stain, culture, resistant to optochin

39

Group D streptococci- 2 subtypes

-Enterococci (faecalis, faecium)
-non-enterococci

40

Enterococci

(faecalis, faecium)
-normal bowel flora
-subacute bacterial endocarditis
-2/3rd most common cause of hospital acquired infection- prosthetic valve endocarditis!!
-resistant to ampicillin, vancomycin!

41

staphylococcus aureus- causes? morphology? treatment?

-acute endocarditis- high fever, chills, myalgias- no history of valvular disease; grow rapidly
-catalase-positive; coagulase-positive!!
-most are penicillin resistant- use nafcillin, dicloxacillin
-cephalosporins- cefazolin, cephalexin
-clindamycin

42

staphylococcus epidermis- morphology, treatment, infects?

-catalase-positive; coagulase neg!!
-vancomycin
-lives in our skin- compromised hospital pts withI lines
-infections of prosthetic valves!!- most frequent organism from infected prosthetic devices!!

43

HACEK organisms- characteristic

-fastidious, very slow growing
-cause endocarditis!!
-Haemophilus
-Actinobacillus
-Cardiobacterium
-Eikenella
-Kingella

44

myocarditis- pathogenesis- most common cause?

-viral infections- most common cause!!
-Coxsackie viruses A and B- most cases
-CMV, HIV, influenza- other cases
-infl cytokines can cause myocardial dysfxn

45

myocarditis- other causes

-nonviral agents- mostly Trypanosoma cruzi (Chagas disease)
-Trichinosis (Trichinella spiralis)- most common helminthic disease
-Lyme disease (Borrelia burgdorferi)
-Diphtheritic myocarditis (Corynebacterium diphtheriae)

46

active myocarditis- morphology

-interstitial infl infiltrate assoc with focal myocyte necrosis
-diffuse, mononuclear, predominantly lymphocyte infiltrate

47

infective endocarditis- essentials of diagnosis

-fever
-preexisting organic heart lesion
-positive blood cultures
-evidence of vegetation on echocardiography
-new or changing heart murmur
-evidence of systemic emboli

48

native valve endocarditis- caused by?

-viridans streptococci
-Group D streptococci
-S aureus
-enterococci
-HACEK group

49

endocarditis- symptoms/signs

-fever!
-duration- few days/wks
-nonspecific symptoms
-peripheral lesions- petechiae, subungual (splinter) hemorrhages, osler nodes, Janeway lesions, Roth spots

50

endocarditis- diagnostic studies

-blood cultures
-modified Duke criteria

51

endocarditis- blood cultures

-3 sets at least 1 hr apart before starting antibiotics

52

endocarditis- treatment?

-agents against staphylococci, streptococci, enterococci
-vancomycin (1 gm every 12 hrs) plus ceftriaxone (2 gm every 12 hrs)!!!!

53

enterococci- treatment

-penicillin
-streptomycin or gentamicin