Infective Endocarditis

Question 1

Difference from infective endarteritis

Answer 1

Infective endarteritis
-involved arteriovenous shunts, arterio-arterial shunts (PDA), or a coarctation of the aorta

Question 2

Classification based on the temporal evolution of disease

Answer 2

1. Acute endocarditis
   - hectically febrile illness that rapidly damages cardiac structures, seeds extracardiac sites, and if untreated, progresses to death within weeks
2. Subacute endocarditis
   - follows an indolent course
   -causes structural cardiac damage only slowly, rarely metastasizes

Question 3

Epidemiology of IE

Answer 3

4-7 per 100,000 population per year in developed countries,

incidence increased in the elderly

Question 4

Predisposed to IE

Answer 4

Congenital heart disease
Ilicit IV drug use
Degenerative valve disease
Intracardiac devices

Question 5

Portals of entry of associated
bacterial species in IE

Answer 5

Oral cavity
Skin
Upper respiratory tract

Question 6

HACEK organisms

Answer 6

Haemophilus species
Aggregatibacter sp
Cardiobacterium hominis
Eikenella corrodens
Kingella kingae

Question 7

Causes of health-care
associated native valve
endocarditis (NVE)

Answer 7

Staphylococcus aureus
coagulase-negative staphylococci (CoNS)
Enterococci

Question 8

Causes of prosthetic valve
endocarditis based on temporal
presentation from surgery

Answer 8

1.Early PVE (2 months)
- nosocomial and is the result of intraoperative contamination
- S. aureus, CoNS, facultative gram-negative bacilli, diphtheroids and fungi

2. Late PVE (>12 months)
   - similar to community-acquired NVE
3. Delayed-onset PVE (2-12 months)
   -nosocomial

Question 9

Causes of CIED endocarditis

Answer 9

• S. aureus and CoNS
• both often resistant to methicillin

Question 10

Causes of endocarditis among
injection drug users

Answer 10

• involves the tricuspid valve
  -caused by S. aureus
  -other causes: P.aeroginosa and Candida sp.
  -unusual - Bacillus, Lactobacillus, and Corynebacterium sp,

Question 11

Causes of blood culture
negative endocarditis

Answer 11

• prior antibiotic exposure (one-third to one-half of cases)
• ## others : streptococci, HACEK, Coxiella burnetti, and Bartonella

Question 12

Pathogenesis of infective
endocarditis

Answer 12

Endothelial injury (at the site of impact of high velocity blood jets or on the low-pressure side of a cardiac structural lesion) -> direct infection by virulent organisms or development of a platelet fibrin thrombus.

-> fibrin deposition combines with platelet aggregation and microorganism proliferation to generate an infected vegetation

Question 13

Clinical Manifestations of IE

Answer 13

Question 14

Modified Duke Criteria for the
clinical diagnosis of IE

Answer 14

Question 15

Definition of definite and
possible IE

Answer 15

Definite IE
- two major criteria
- 1 major and 3 minor
- 5 minor criteria

Probable IE
- one major and one minor criterion
-three minor criteria

Question 16

Considerations in performing
blood culture studies

Answer 16

Patients with suspected IE who have not received antibiotics during the prior 2 weeks:
- three 2-bottle blood culture sets, separated from one another by at least 2 hours, should be obtained from different venipuncture sites over 24h

If cultures remain negative after 48-72 h, additional blood culture sets should be obtained

Hemodynamically stable/subacute IE: may withheld empirical antibiotic tx initially

Deteriorating hemodynamics/requires urgent surgery: may give empirical antibiotic tx

Question 17

Role of serologic tests in IE

Answer 17

used to implicate organisms that are difficult to recover by blood culture: Brucella, Bartonella, Legionella, Chlamydia psittaci, and C. burnetti

Question 18

Choice of echocardiographic
techniques in IE work-up

Answer 18

Transthoracic echocardiography (TTE)

Question 19

Principles in antimicrobial
therapy of IE

Answer 19

To cure endocarditis, all bacteria in the vegetation must be killed. Therapy must be bactericidal and prolonged

Question 20

Antibiotic treatment for Streptococci

Answer 20

Question 21

Antibiotic tx for Enterococci

Answer 21

Question 22

Antibiotic tx for Staphylococci

Answer 22

Question 23

Antibiotic tx for HACEK

Answer 23

Question 24

Antibiotic tx for Coxiella burnetti

Answer 24

Question 25

Antibiotic tx for Bartonella

Answer 25

Question 26

Candidates for Outpatient Antimicrobial Therapy

Answer 26

Fully compliant
Clinically stable
No longer bacteremic
No febrile
No clinical or echocardiographic findings that suggest an impending complication

Question 27

Monitoring antimicrobial therapy

Answer 27

Blood cultures should be repeated daily until sterile in patients with IE due to S. aureus or difficult-to-treat organisms
-rpt again 4-6 weeks after tx to document cure

Blood cultures become sterile after:
2 days - viridans Step, HACEK, entrerococci
3-5 days - S. aureus
7-9 days - MRSA

Question 28

Diseases to evaluate if fever persists for 7 days despite appropriate antibiotic therapy

Answer 28

paravalvular abscess
extracardiac abscesses (spleen, kidney)
complications (embolic events)

Question 29

Indications for surgical
management in IE

Answer 29

Question 30

Recommendations on IE
prophylaxis

Answer 30

-recommended when there is manipulation of gingival tissue or the periapical region of the teeh or perforation of the oral mucosa (including surgery on the respiratory tract)
-not advised for GI or GU procedures
-high-risk patients should be treated before or when they undergo procedures on an infected GUT or infected skin

Question 31

Dose of prophylaxis

Answer 31