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RC Test 1 > B4.013 Prework 1 Infectious Cardiac Valve Disease > Flashcards

B4.013 Prework 1 Infectious Cardiac Valve Disease Flashcards

1
Q

what are valve vegetations made up of?

A

platelets, fibrin, microbes, collagen

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2
Q

what are 4 different ways to classify infective endocarditis

A

temporal evolution
cause of infection
site of infection
predisposing risk factor

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3
Q

what is acute endocarditis

A

febrile illness that rapidly damages cardiac structures, seeds extracardiac sites via bloodstream, and, if untreated progresses to death within weeks

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4
Q

typical picture of acute endocarditis

A

caused by high virulence organisms involving a normal valve
large vegetations more prone to embolize
higher mortality, harder to cure with antibiotics
higher incidence of surgical treatment
s.aureus most common causative organism

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5
Q

what is subacute endocarditis (SBE)

A

an indolent, febrile illness developing over weeks to months

new or changing cardiac murmur and embolic phenomena on exam

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6
Q

typical picture of SBE

A

usually lower virulence organisms
strep viridans, enterococci, HACEK most common
smaller vegetations usually on abnormal or diseases valves
less likely to cause tissue/structural damage
higher cure rate w antibiotics

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7
Q

how can partially treated acute endocarditis present?

A

as SBE

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8
Q

most common cause of infective endocarditis

A

strep viridans (50-60%)

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9
Q

most common cause of IE in IV drug users

A

s. aureus (20-30%)

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10
Q

most common cause of acute IE

A

s.aureus

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11
Q

most common cause of prosthetic valve endocarditis

A

staph epidermidis

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12
Q

IE causative organism with underlying colon polyps/cancer

A

strep gallolyticus (bovus)

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13
Q

IE causative organisms commonly associated with neg blood cultures

A 
Hemophilus
Actinobacillus
Cardiobacterium
Ekinella
Kingella
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14
Q

IE causative organism in immunocompromised patients

A

fungi (candida)

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15
Q

what % of IE cases are culture neg

A

10%

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16
Q

common organisms w oral, skin, resp portals of entry

A

strep viridans
staph
HACEK

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17
Q

GI portal of entry

A

strep gallolyticus (bovus)

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18
Q

GU portal of entry

A

enterococci

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19
Q

most common cause of community acquired endocarditis

A

strep viridans from dental procedures or poor dental hygiene

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20
Q

characterize nosocomial endocarditis

A

> 72 hours post admission or within 6-8 weeks after hospital procedure
3x increase in mortality over community acquires
6-25% of IV catheter related bacteremia results in endocarditis

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21
Q

most common organisms in nosocomial endocarditis

A

staph aureus
coag neg staph
enterococci

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22
Q

characterize prosthetic valve endocarditis

A

within 2 months of surgery

s. aureus, coag neg staph, fungi

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23
Q

characterize pacemaker/ICD associated endocarditis

A

within weeks of procedure

s. aureus, coag neg staph

24
Q

what is a common virulence factor of organisms that cause endocarditis

A

surface adhesion molecules
fibronectin binding proteins - gram +
clumping factor- staph aureus
glucans/FimA- strep

25
Q

how do microcolonies form?

A

organisms enmesh into growing platelet/fibrin vegetations and proliferate

26
Q

why are microcolonies hard to treat?

A

organisms deep within vegetation are metabolically inactive and resistant to killing by antimicrobial agents
proliferating surface organisms are shed into blood continuously

27
Q

what allows for infection of the typically resistant endothelium in the heart?

A

endothelial injury (at site of impact of high velocity blood jets or on low P side of cardiac structural lesion)

28
Q

what is NBTE

A

non bacterial thrombotic endocarditis
uninfected platelet-fibrin thrombus on valve
subsequently serves as a site of bacterial attachment during transient bacteremia

29
Q

which organism can adhere directly to intact endothelium? i.e. doesn’t require a site of NBTE

A

staph aureus

30
Q

how do organisms induce platelet deposition and a procoagulant state?

A

elicit TF from endothelium

31
Q

describe the morphology of IE

A

friable, bulky, potentially destructive lesions on valves
contain fibrin, inflamm cells, bacteria, and other organisms
can be single or multiple
occasionally erode into underlying myocardium and produce abscess or fistula

32
Q

what can happens if a IE vegetation embolizes?

A

embolic fragments often contain virulent organisms
can develop abscesses where they lodge
septic infarcts or mycotic aneurysms can develop

33
Q

how do vegetations of SBE differ from those of acute endocarditis?

A

SBE are associated w less destruction
exhibit granulation tissue at their bases indicative of healing
fibrosis, calcification, chronic inflamm infiltrate can develop

34
Q

structural risk factors for IE

A 
prior endocarditis
rheumatic heart disease
degenerative mitral valve (prolapse)
bicuspid aortic valve
prosthetic valve
intravascular device
atrial septal defect
ventricular septal defect
tetralogy of Fallot
35
Q

risk factors for bacteremia

A 
IV drug  use
indwelling venous catheters
poor dentition
hemodialysis
DM
36
Q

common clinical manifestations of infective endocarditis

A 
fever
elevated ESR
chills and sweats
murmur
anemia
37
Q

remote embolic effects of IE

A 
brain infarcts
retinal infarction
petechiae of skin and finger clubbing
mycotic aneurysms of splenic arteries and/or infarct of spleen (splenomegaly)
petechiae and gross infarcts of kidney
petechiae of mucous membranes
38
Q

classic IE physical findings

A

Roth’s spots
Osler’s nodes
Splinter hemorrhages
Janeway lesions

39
Q

Roths spots

A

retinal hemorrhages with white or pale centers

40
Q

osler nodes

A

painful, red, raised lesions on hands and feet

41
Q

janeway lesions

A

nontender, small erythematous or hemorrhagic macular or nodular lesions on the palms or soles

42
Q

clinical presentation of fungal endocarditis

A 
extremely debilitating
present w constitutional symptoms
candida most common
immunocompromised or IV drug user
low rate of pos blood cultures
43
Q

diagnosis of IE

A

modified Duke criteria
pos blood cultures
echocardiography

44
Q

blood culture technique for IE

A

2-3 bottles from different sites
drawn >30 min apart
aseptic technique to avoid false pos
don’t draw from IV lines

45
Q

what is a reason for false neg results?

A

prior antibiotic use (draw >48 h after antibiotics)
fungal
HACEK
-if culture is neg, repeat in 7 days

46
Q

accepted blood culture contam rate

A

< 3%

47
Q

what are some important findings of echocardiography

A

anatomic confirmation of endocarditis
vegetation size
intracardiac complications
assessment of cardiac function

48
Q

TTE

A

trans thoracic echo
non invasive, but difficult in 20% of pts
65% sense, high spec

49
Q

TEE

A 
trans esophageal echo
90% sense
needed for:
prosthetic valve endocarditis
myocardial abscesses, valve perf, intracardiac fistula
50
Q

complications of IE

A 
valvular regurg
CHF (severe regurg) (aortic or mitral)
cerebrovascular emboli or stroke
peripheral arterial emboli
mycotic aneurysm
splenic abscess/infarct
para-prosthetic valve abscess/dehiscence
intracardiac fistula
cardiac conduction system abnormalities (myocardial abscess)
51
Q

what is a mycotic aneurysm

A

focal dilation of an artery caused by growth of microorganisms within the vascular wall, usually after the impact of a septic embolus

52
Q

monitoring anti microbial therapy in IE

A

antibiotic toxicities occur in 25-40% of patients, commonly in 3rd week
blood tests to detect renal, hepatic, hematologic toxicity should be performed periodically
cultures repeated daily until sterile, recheck is there is a recurring fever and performed 4-6 weeks post therapy to document cure

53
Q

when is surgery required for optimal outcome?

A

heart failure due to valve damage
failure of antibiotic therapy
partially dehisced prosthetic valve
s.auerus prosthetic valve endocarditis w intracardiac complication

54
Q

when should surgery be strongly considered

A 
perivalvular extension
persistent unexplained fever in culture neg
large vegetations on left heart
recurrent emboli when on antibiotics
abscess formation
fungal
large, hypermobile vegetations
55
Q

when is endocarditis prophylaxis recommended

A

for people w prosthetic valves, previous endocarditis, cardiac transplant, or congenital cyanotic heart disease
when they get dental or resp procedures

56
Q

most important way to avoid endocarditis

A

routine maintenance of good oral hygiene

RC Test 1 (19 decks)

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