Infective Endocarditis

Question 1

What is infective endocarditis?

Answer 1

Microbial infection of the endocardium.

Question 2

What is a vegetation?

Answer 2

the classic lesion of this disease

Question 3

3 types

Answer 3

acute, subacute, chronic

Question 4

Native?

Answer 4

Endocarditis of the valves.

Question 5

Prostetic

Answer 5

duh

Question 6

Two mechanisms of bacterial adherence to the valvular endothelium?

Answer 6

Direct contact leading to a coagulum which pathogens bind to. Leads to a progressively larger vegetation.
Local inflammation promotes the expression of transmembrane proteins like FIBRONECTIN. Pathogens like S. aureus can bind fibronectin.

Question 7

Describe the pathogenesis of Endocarditis

Answer 7

First there is an injury caused by either a high velocity of blood flow due to an abnormal valve or some sort of intravascular hardware. This injury leads to platelett adherence and thrombus formation. If bacteria enter the bloodstream, they adhere to the injured surface.

Question 8

Complications of IE

Answer 8

Embolization, Metastatic infection, valve destruction, immune complex injury, local extension of infection

Question 9

What sex is more likely to get IE

Answer 9

Men unless under 30…then women carry a higher risk.

Question 10

Most common risk factor

Answer 10

Degenerative heart disease

Question 11

Most common underlying cardiac lesions

Answer 11

MVP,Degenerative valvular lesions, Bicuspid aortic valve, prosthetic valve

Question 12

In regards to prosthetic valve endocarditis, what organism is most responsible for IE that is aquired less than 1 year after surgery? More than 1 year?

Answer 12

Staph under 1 year

More closely resembles native valve endocarditis over 1 year out

Question 13

Aortic root abcess is most common with what type of endocarditis?

Answer 13

Aortic Prosthetic valve endocarditis

Question 14

Most common organism?

Answer 14

GRAM POSITIVE

Most common = Staph Aureus (acute IE)

Question 15

Viridians strptococci seen where

Answer 15

Subacute IE (70%)

Question 16

Common gram Negatives

Answer 16

HACEK
Haphrophilus- most common
Actinomycetocomitans
C hominis
Ecceredens
Kingae

Question 17

When do we see fungal endocarditis

Answer 17

IV drug use….Candida most common

Question 18

Most common cause of culture negative Endocarditis

Answer 18

Prior antibiotic use- prevents the organism from growing in culture

Question 19

Nosocomial IE (hospital acquired) usually due to?

Answer 19

Infected lines

Question 20

Most common valve affected in IE from IVDU?

Answer 20

Tricuspid

Question 21

Common IE presentation

Answer 21

Fever, chills, poor appetite, weight loss

Question 22

30% may have emboli to brain, lung, or spleen.

Answer 22

True, seen more frequently in the developing world.

Question 23

Subacute IE usually presents with what type of symptoms?

Answer 23

Nonspecific (fever, sweats, dyspnea, weakness, anorexia)

Question 24

Physical findings

Answer 24

Splinter hemorrhages, Osler's nodes, Janeway  lesions
Petechiae
Roth spots on fundoscopic exams
Heart murmurs
Enlarged or tender spleen

Question 25

Read over Duke Criteria …pg 10

Answer 25

ok

Question 26

In subacute pts, you may be able to withhold treatment for a short period of time in order to get blood cultures. In pts with high fever, sepsis, other acute signs…must give antibiotics. Take a blood sample first though

Answer 26

True

Question 27

What diagnostic approach do you take with Culture negative Endocarditis?

Answer 27

More cultures, serological testing for the ella species, PCR of infected material.

Question 28

TEE?

Answer 28

Transesophageal echocardiogram…more sensitive than transthoracic. TEE is of benefit when evaluating right sided heart valves.

Question 29

Echocardiography guidelines

Answer 29

TTE initially, TEE in pts with prosthetic valves.

Detection of a vegetation with TTE is a positive test. Negative studies should be followd with TEE

Question 30

In low risk pts, a negative TTE makes IE

Answer 30

Unlikely

Question 31

Five risk factors that, when absent, make IE unlikely as long as the TTE in negative?

Answer 31

prosthetic valve, + blood culture, IV drug misuse, central venous line, signs of embolism

Question 32

Limitations of echocardiography

Answer 32

Falsely negative early in disease, False positive with thickened valve leaflets, Inability to distinguish healed from active vegetations, Lower sensitivity in those with prostheses.

Question 33

Management of IE

Answer 33

Iv Antibiotics 4-6 weeks, close management for continued infection or further valve injury

Question 34

Who needs urgent surgery?

Answer 34

Hemodynamics compromised due to valve destruction
Persistent fever even with Antibiotics,
Development of abcesses or fistulae due to perivalvular infection
Involvement of highly resistant organisms
Large vegetations greater than 1 cm