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Cardiovascular II > Microbiology of Heart Disease Hersh DSA > Flashcards

Microbiology of Heart Disease Hersh DSA Flashcards

1
Q

serous pericarditis

A

produced by noninfectious infl diseases (rheumatic fever, SLE, scleroderma), tumors, uremia

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2
Q

fibrinous and serofibrinous pericarditis- composed of? causes?

A
  • most frequent types of pericarditis!
  • serous fluid mixed with fibrinous exudate
  • acute MI
  • postinfarction (Dressler) syndrome (autoimmune response days/wks after MI)
  • uremia
  • chest radiation
  • rheumatic fever, SLE
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3
Q

fibrinous and serofibrinous pericarditis- symptoms

A
  • pain (sharp, pleuritic, position dependent) and fever!!

- loud pericardial friction rub- most striking finding!!!

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4
Q

purulent or suppurative pericarditis- caused by? outcome?

A
  • active infection caused by microbial invasion of pericardial space (via direct extension, blood, lymph, cardiotomy)
  • serosal surfaces are reddened, granular, coated with exudate
  • outcome- scarring- frequently produces constrictive pericarditis?
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5
Q

hemorrhagic pericarditis- composed of? caused by?

A
  • exudate of blood mixed with fibrinous or suppurative effusion
  • caused by malignant neoplasm spread to pericardial space
  • also found in bacterial infections, in pts with bleeding diathesis and tb
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6
Q

caseous pericarditis- caused by?

A
  • tb!! and fungal infections
  • spread from tb foci within tracheobronchial nodes
  • common antecedent of disabling, fibrocalcific, chronic constrictive pericarditis
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7
Q

chronic or healed pericarditis

A
  • plaque-like fibrosis thickenings of serosal membranes
  • thin, delicate lesions
  • adhesive pericarditis- fibrosis in mesh-like stringy adhesions-obliterates the pericardial sac
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8
Q

adhesive mediastinopericarditis- after? effects?

A
  • after infectious pericarditis, cardiac surgery, or mediastinal irradiation
  • obliterated pericardial sac- adherence of external aspect of parietal layer to surround structures- strains cardiac fxn!!
  • hearts pulls against parietal pericardium and surround structures
  • systolic retraction of rib cage and diaphragm- pulsus paradoxus
  • cardiac hypertrophy and dilatoin
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9
Q

constrictive pericarditis- effects? signs?

A
  • heart encases in a dense, fibrous or fibrocalcific scar that limits diastolic expansion and CO
  • fibrous scar obliterates the pericardial space and sometimes calcifying- if extreme resembles a plaster mold (concretio cordis)
  • dense enclosing scar- cardiac hypertrophy cannot occur
  • CO reduced at rest- heart cannot inc its output in response to inc demands
  • signs- muffled heart sounds, elevated jugular venous P, peripheral edema
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10
Q

acute pericarditis- diagnosis

A
  • anterior pleuritic chest pain, worse supine
  • pericardial rub
  • fever common
  • erythrocyte sedimentation rate usually elevated
  • ECG- diffuse ST-segment elevation, PR depression
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11
Q

pericarditis- treatment?

A
  • NSAIDs
  • colchicine- helps prevent recurrences
  • ibuprofen (600-800 mg 3x daily for 1-2 wks) or indomethacin (50 mg 3x daily)
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12
Q

post-MI pericarditis- treatment

A
  • aspirin and colchicine (instead of NSAIDs)
  • aspirin (650-1000 mg 3x daily for 1-2 wks)
  • colchicine (3 months)
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13
Q

pericarditis treatment- if colchicine therapy fails?

A

-immunosuppression (cyclophosphamide or methotrexate)

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14
Q

Picornaviridae- 2 subtypes

A 
1- Enteroviridae (infect intestinal epit and lymphoid cells- excreted in feces and spread fecal-oral route):
-poliovirus
-coxsackie A and B
-echovirus
2- Rhinoviridae (common cold)
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15
Q

Coxsackie B- causes?

A
  • pleurodynia (resp infection)

- myocarditis/pericarditis (50% of cases!!)- self-limited chest pain or serious arrhythmias, cardiomyopathy, HF

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16
Q

Mycobacterium tb- morphology

A
  • 40% of total cell dry weight is lipid
  • mycolic acids
  • thin rods
  • non-motile
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17
Q

Mycobacterium tb- metabolism

A
  • aerobic
  • catalase-positive
  • slow growth rate
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18
Q

Mycobacterium tb- virulence

A
  • mycosides- cord factor, sulfatides, wax D
  • iron siderophore
  • facultative intracellular growth
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19
Q

Mycobacterium tb- clinical

A
  • primary- asymptomatic, overt disease involving lungs or other organs
  • reactivation/secondary- pulm, pleural or pericardial, LN, kidney, skeletal joints, CNS
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20
Q

Mycobacterium tb- diagnositcs

A
  • acid-fast stain
  • RAPID CULTURE
  • PPD skin test
  • IGRA (interferon gamma release assay)
  • chest xray
  • Gene Xpert MT/Rif
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21
Q

mycobacterium endocarditis- treatment

A
  • isoniazid
  • rifampin
  • pyrazinamide
  • ethambutol
  • streptomycin
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22
Q

infective endocarditis

A

-microbial infection of heart valves- leads formation of vegetations composed of thrombotic debris and organisms, often assoc with destruction of underlying cardiac tissues

23
Q

acute infective endocarditis- caused by?

A
  • prev normal heart valve by a highly virulent organism (staph aureus)- rapidly produces necrotizing lesions
  • difficult to cure with antibiotics; need surgery
  • death can occur within days/wks
24
Q

subacute infective endocarditis- caused by?

A
  • organisms with lower virulences (viridans streptococci)- infections of deformed valves with less destruction
  • course days/wks; cured with antibiotics
25
Q

risks of developing infective endocarditis

A
  • rheumatic heart disease with valvular scarring
  • mitral vavle prolapse
  • degenerative calcific valvular stenosis
  • bicuspid aortic valve
  • artifiial valves
26
Q

endocarditis of prev damaged/abnormal valves- caused by?

A

streptococcus viridans (50%)

27
Q

endocarditis of healthy valves- caused by??

A

-S aureus (20-30%)- major in IV drug abusers

28
Q

endocarditis- other bacterial causes

A
  • Haemophilus
  • Actinobacillus
  • Cardiobacterium
  • Eikenella
  • Kingella
29
Q

prosthetic valve endocarditis- caused by?

A

S epidermidis (coagulase-neg)

30
Q

IE- morphology

A
  • vegetations on heart valves!- friable, bulky, destructive lesions containing fibrin, infl cells, bacteria
  • aortic and mitral valves most common
  • prone to embolization
31
Q

acute endocarditis- clinical features

A
  • fevers, chills, weakness, lassitude
  • fever- most consistent sign!!
  • murmurs- 90% of pts with left-sided IE
32
Q

acute endocarditis- complications

A
  • 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
Q

4 major forms of vegetative endocarditis- morphology

A
  • 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
Q

Duke criteria- pathologic

A
  • microorganisms by culture or histologic examination in a vegetation, embolus, or intracardiac abscess
  • histologic confirmation of active endocarditis in vegetation or intracardiac abscess
35
Q

Duke criteria- clinical- major

A
  • 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
Q

Duke criteria- clinical- minor

A
  • 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
Q

Viridans Group Streptococci- 3 main types of infection

A
  • dental infections (streptococci mutans)
  • endocarditis (viridans streptococcus- slowly/subacute; staph aureus- fast/acute)
  • abscesses (streptococcus intermedius)
38
Q

Viridans Group Streptococci- virulence, treatment, diagnostics

A
  • normal oral flora and GI tract
  • extracellular dextran- helps bind to heart valves
  • penicillin G
  • gram stain, culture, resistant to optochin
39
Q

Group D streptococci- 2 subtypes

A
  • Enterococci (faecalis, faecium)

- non-enterococci

40
Q

Enterococci

A

(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
Q

staphylococcus aureus- causes? morphology? treatment?

A
  • 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
Q

staphylococcus epidermis- morphology, treatment, infects?

A
  • 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
Q

HACEK organisms- characteristic

A
  • fastidious, very slow growing
  • cause endocarditis!!
  • Haemophilus
  • Actinobacillus
  • Cardiobacterium
  • Eikenella
  • Kingella
44
Q

myocarditis- pathogenesis- most common cause?

A
  • viral infections- most common cause!!
  • Coxsackie viruses A and B- most cases
  • CMV, HIV, influenza- other cases
  • infl cytokines can cause myocardial dysfxn
45
Q

myocarditis- other causes

A
  • nonviral agents- mostly Trypanosoma cruzi (Chagas disease)
  • Trichinosis (Trichinella spiralis)- most common helminthic disease
  • Lyme disease (Borrelia burgdorferi)
  • Diphtheritic myocarditis (Corynebacterium diphtheriae)
46
Q

active myocarditis- morphology

A
  • interstitial infl infiltrate assoc with focal myocyte necrosis
  • diffuse, mononuclear, predominantly lymphocyte infiltrate
47
Q

infective endocarditis- essentials of diagnosis

A
  • fever
  • preexisting organic heart lesion
  • positive blood cultures
  • evidence of vegetation on echocardiography
  • new or changing heart murmur
  • evidence of systemic emboli
48
Q

native valve endocarditis- caused by?

A
  • viridans streptococci
  • Group D streptococci
  • S aureus
  • enterococci
  • HACEK group
49
Q

endocarditis- symptoms/signs

A
  • fever!
  • duration- few days/wks
  • nonspecific symptoms
  • peripheral lesions- petechiae, subungual (splinter) hemorrhages, osler nodes, Janeway lesions, Roth spots
50
Q

endocarditis- diagnostic studies

A
  • blood cultures

- modified Duke criteria

51
Q

endocarditis- blood cultures

A

-3 sets at least 1 hr apart before starting antibiotics

52
Q

endocarditis- treatment?

A
  • agents against staphylococci, streptococci, enterococci

- vancomycin (1 gm every 12 hrs) plus ceftriaxone (2 gm every 12 hrs)!!!!

53
Q

enterococci- treatment

A
  • penicillin

- streptomycin or gentamicin

Cardiovascular II (13 decks)

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