Infective Endocarditis

Question 1

Epidemiology

Answer 1

uncommon
adults
slightly more in males

usually on the valves more so than other areas of endocardium

Question 2

Characteristics

Answer 2

causes “vegetations”

Question 3

vegetations

Answer 3

friable masses of blood clot and infecting organisms

Question 4

friable

Answer 4

the ability of a solid substance to be reduced to smaller pieces with little effort.

Question 5

pathogenesis

Answer 5

1. valvular endothelial injury
2. platelet and fibrin deposition
3. microbial seeding
4. microbial multiplication

Question 6

prognosis

Answer 6

100% fatal if undiagnosed and untreated

20% fatal if diagnosed and treated appropriately (IV antibiotics and/or surgery)

Question 7

3 classification systems

Answer 7

1. clinical course
2. host substrate
3. specific infecting organism

Question 8

classification via clinical course

Answer 8

acute bacterial endocarditis (ABE) vs.

subacute bacterial endocarditis (SBE)

Question 9

ABE

Answer 9

usually fulminant and due to highly virulent organisms (i.e. S. aureus)

Question 10

SBE

Answer 10

insidious onset over weeks and due to less virulent organisms (viridans streptococci)

Question 11

classification via host substrate

Answer 11

native valve endocarditis (NVE) versus
Prosthetic valve endocarditis (PVE) versus
edocarditis in IVDU

Question 12

PVE

Answer 12

commonly due to coag negative S. epidermis, which is rare in NVE

Question 13

Endocarditis in IVDU

Answer 13

commonly acute and commonly on tricuspid valve

Question 14

classification via specific infecting organism

Answer 14

i.e. pseudomonas aeruginosa endocarditis

Question 15

Anatomic sites of IE

Answer 15

Left-sided valves….75%
Right-sided valves…15%
Both…5%
Other…..5%

Mitral valve alone....35%-------|
Aortic valve alone...20%-------|-->75%
Mitral and aortic...20%---------|
Tricuspid...14%------|
Pulmonic....1%------|-->15%

Question 16

What percentage of pts w/ IE have predisposing heart disease?

Answer 16

70%

Question 17

What are some predisposing heart diseases?

Answer 17

MVP
congenital disease
prosthetic valve
degenerative disease
rheumatic disease
previous endocarditis

Question 18

portals of entry for organisms causing IE

Answer 18

central venous catheterization
endoscopy
shaving
dental procedures
gingivitis
chewing
brushing teeth
surgery
bladder catheterization
IVDU
etc.

Question 19

correlation b/w ability of bug to cause IE and its ability to…

Answer 19

adhere to blood clot

Question 20

dextran

Answer 20

facilitates adherence of some streptococci to blood cot

(cell wall component)

esp. streptococcus mutans… a viridans that causes dental caries by same MOA

Question 21

Most common etiological agents of IE in tertiary care hospitals

Answer 21

1. Staphylococci in 42%
   —-S. aureus in 32%
   —-CoagNS in 10%
2. Streptococci 40%
   —-Viridans group (oral flora) 18%
   —-enterococci 11%
   —-S. bovis (assoc. w/ colon cancer) in 6%
   —-others 5%
   (In RURAL settings, viridans=more common cause than S. aureus!)
3. HACEK group bacteria 4%
4. other gram-negative aerobes 3%
5. fungi (esp. Candida) 2%

NEGATVE BLOOD CULTURES or multiple causative organisms…9%

Question 22

HACEK

Answer 22

fastidious slow-growing oral flora)

Question 23

gross pathology

Answer 23

–large (up to 3cm), friable vegetations
(some combo of tan, gray, red, or brown)
–range of # of vegetation (1 to many)
–vegetations usually located on line of valve closure (the atrial side of AV valves, or ventricular side of semilunar valves)

Question 24

the larger the vegetation…

Answer 24

the more likely it is to be infected

Question 25

IE consequences

Answer 25

``` destructive of tissue may cause perforation of valve adjacent abscess fibrotic scarring calcification ```

Question 26

microscopic pathology of the vegetations

Answer 26

fibrin platelets masses of organisms sometimes necrois and neutrophils later, lymphocytes, macrophages, fibroblasts may infiltrate and fibrosis may occur

Question 27

Common symptoms

Answer 27

**fever chills weakness dyspnea

Question 28

Less common symptoms

Answer 28

``` cough sweats anorexia weight loss malaise skin lesions nausea/vomiting stroke headache myalgia/arrthralgia edema chest pain abdominal pain delirium/coma back pain hemptysis ```

Question 29

Common physical signs

Answer 29

fever heart murmur splenomegaly petechiae

Question 30

uncommon physical signs

Answer 30

``` Osler nodes subungual splinter hemorrhages changing heart murmur Janeway lesions new heart murmur Roth spots ```

Question 31

Osler nodes

Answer 31

pea-sized tender finger/toe nodules

Question 32

Janeway lesions

Answer 32

small palm/sole hemorrhages

Question 33

Roth spots

Answer 33

white dots w/ surrounding hemorrhage in retina

Question 34

Uncommon signs vs common signs

Answer 34

the uncommon signs are more specific

Question 35

Common lab findings

Answer 35

elevated ESR circulating immune complexes anemia proteinuria

Question 36

Less common lab findings

Answer 36

``` rheumatoid factor hematuria leukocytosis hypergammaglobulinemia elevated creatinine leukopenia thrombocytopenia ```

Question 37

Rheumatoid factor

Answer 37

anti-IgG antibodies

Question 38

characteristic of endocarditis

Answer 38

continuous low-grade bacteremia

Question 39

Blood cultures

Answer 39

Some types need special cultures for fastidious organisms...hod cultures longer **critical for specific diagnosis may be negative if already received antibiotics

Question 40

What can show vegetations in 60% of cases?

Answer 40

transthoracic echocardiography

Question 41

what has greater than 90% sensitivity?

Answer 41

transesophageal echocardiography

Question 42

does the absence of vegetations on echocardiogram exclude diagnosis of endocarditis?

Answer 42

No!

Question 43

Duke Criteria for infective endocarditis

Answer 43

requires 2 major, OR 1 major and 3 minor, OR 5 minor criteria fulfilled for a diagnosis

Question 44

Complications

Answer 44

``` HF septic emboli --kidneys --heart --spleen --brain ```

Question 45

More uncommon complications

Answer 45

Myocardial abscess GN "mycotic aneurysm" pericarditis

Question 46

If suspect IE...

Answer 46

don't wait for echo... get the blood cultures, put "suspect endocarditis" on requisition, and start antibiotic therapy!