B4.013 Prework 1 Infectious Cardiac Valve Disease

Question 1

what are valve vegetations made up of?

Answer 1

platelets, fibrin, microbes, collagen

Question 2

what are 4 different ways to classify infective endocarditis

Answer 2

temporal evolution
cause of infection
site of infection
predisposing risk factor

Question 3

what is acute endocarditis

Answer 3

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

Question 4

typical picture of acute endocarditis

Answer 4

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

Question 5

what is subacute endocarditis (SBE)

Answer 5

an indolent, febrile illness developing over weeks to months

new or changing cardiac murmur and embolic phenomena on exam

Question 6

typical picture of SBE

Answer 6

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

Question 7

how can partially treated acute endocarditis present?

Answer 7

as SBE

Question 8

most common cause of infective endocarditis

Answer 8

strep viridans (50-60%)

Question 9

most common cause of IE in IV drug users

Answer 9

s. aureus (20-30%)

Question 10

most common cause of acute IE

Answer 10

s.aureus

Question 11

most common cause of prosthetic valve endocarditis

Answer 11

staph epidermidis

Question 12

IE causative organism with underlying colon polyps/cancer

Answer 12

strep gallolyticus (bovus)

Question 13

IE causative organisms commonly associated with neg blood cultures

Answer 13

Hemophilus
Actinobacillus
Cardiobacterium
Ekinella
Kingella

Question 14

IE causative organism in immunocompromised patients

Answer 14

fungi (candida)

Question 15

what % of IE cases are culture neg

Answer 15

10%

Question 16

common organisms w oral, skin, resp portals of entry

Answer 16

strep viridans
staph
HACEK

Question 17

GI portal of entry

Answer 17

strep gallolyticus (bovus)

Question 18

GU portal of entry

Answer 18

enterococci

Question 19

most common cause of community acquired endocarditis

Answer 19

strep viridans from dental procedures or poor dental hygiene

Question 20

characterize nosocomial endocarditis

Answer 20

> 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

Question 21

most common organisms in nosocomial endocarditis

Answer 21

staph aureus
coag neg staph
enterococci

Question 22

characterize prosthetic valve endocarditis

Answer 22

within 2 months of surgery

s. aureus, coag neg staph, fungi

Question 23

characterize pacemaker/ICD associated endocarditis

Answer 23

within weeks of procedure

s. aureus, coag neg staph

Question 24

what is a common virulence factor of organisms that cause endocarditis

Answer 24

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

Question 25

how do microcolonies form?

Answer 25

organisms enmesh into growing platelet/fibrin vegetations and proliferate

Question 26

why are microcolonies hard to treat?

Answer 26

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

Question 27

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

Answer 27

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

Question 28

what is NBTE

Answer 28

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

Question 29

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

Answer 29

staph aureus

Question 30

how do organisms induce platelet deposition and a procoagulant state?

Answer 30

elicit TF from endothelium

Question 31

describe the morphology of IE

Answer 31

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

Question 32

what can happens if a IE vegetation embolizes?

Answer 32

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

Question 33

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

Answer 33

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

Question 34

structural risk factors for IE

Answer 34

``` 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 ```

Question 35

risk factors for bacteremia

Answer 35

``` IV drug use indwelling venous catheters poor dentition hemodialysis DM ```

Question 36

common clinical manifestations of infective endocarditis

Answer 36

``` fever elevated ESR chills and sweats murmur anemia ```

Question 37

remote embolic effects of IE

Answer 37

``` 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 ```

Question 38

classic IE physical findings

Answer 38

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

Question 39

Roths spots

Answer 39

retinal hemorrhages with white or pale centers

Question 40

osler nodes

Answer 40

painful, red, raised lesions on hands and feet

Question 41

janeway lesions

Answer 41

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

Question 42

clinical presentation of fungal endocarditis

Answer 42

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

Question 43

diagnosis of IE

Answer 43

modified Duke criteria pos blood cultures echocardiography

Question 44

blood culture technique for IE

Answer 44

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

Question 45

what is a reason for false neg results?

Answer 45

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

Question 46

accepted blood culture contam rate

Answer 46

< 3%

Question 47

what are some important findings of echocardiography

Answer 47

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

Question 48

TTE

Answer 48

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

Question 49

TEE

Answer 49

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

Question 50

complications of IE

Answer 50

``` 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) ```

Question 51

what is a mycotic aneurysm

Answer 51

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

Question 52

monitoring anti microbial therapy in IE

Answer 52

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

Question 53

when is surgery required for optimal outcome?

Answer 53

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

Question 54

when should surgery be strongly considered

Answer 54

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

Question 55

when is endocarditis prophylaxis recommended

Answer 55

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

Question 56

most important way to avoid endocarditis

Answer 56

routine maintenance of good oral hygiene