3. Definition
Infectious Endocarditis (IE):
• An infection of the heart’s endocardial surface
• Vegetation
– Variable in size
– Amorphous mass of fibrin & platelets
– Abundant organisms
– Few inflammatory cells
• Classified into four groups:
• Native Valve IE
• Prosthetic Valve IE
• Intravenous drug abuse (IVDA) IE
• Nosocomial IE
4. PREDISPOSING CONDITIONS ASSOCIATED WITH
INCREASED RISK OF ENDOCARDITIS
More Common
• Rheumatic heart disease
• Mitral valve prolapse with murmur
• Degenerative valvular disease
• Intravenous drug use
• Prosthetic valve
• Congenital abnormalities (valvular or septal
defect)
5. Less Common
• Hypertrophic obstructive cardiomyopathy
• Pulmonary-systemic shunts
• Coarctation of the aorta
• Previous endocarditis
6. Infecting Organisms
Common bacteria
– S. aureus
– Streptococci
– Enterococci
Uncommon bacteria
– Fungi
– Pseudomonas
– The HACEK grop
» Haemophilus sp.
» Actinobacillus
» Cardiobacterium
» Eikenella
» Kingella
7. Acute V Sub-acute
• Acute
– Toxic presentation
– Progressive valve destruction & metastatic infection
developing in days to weeks
– Most commonly caused by S. aureus
• Subacute
– Mild toxicity
– Presentation over weeks to months
– Rarely leads to metastatic infection
– Most commonly S. viridans or enterococcus
8. Infective Endocarditis
• Intravenous Drug Abuse
- S. aureus
– Increased frequency of gram negative infection
such as P. aeruginosa & fungal infections
– High concordance of HIV positivity & IE
• HIV status does not in itself modify clinical
picture
• Survival is decreased if CD4 count < 200/mm3
9. Pathophysiology
• Turbulent blood flow disrupts the
endocardium making it “sticky”
• Bacteremia delivers the organisms to the
endocardial surface
• Adherence of the organisms to the
endocardial surface
• Eventual invasion of the valvular leaflets
10. Infective Endocarditis
• Pathology
– NVE infection is largely confined to leaflets
– PVE infection commonly extends beyond valve
ring into annulus/periannular tissue
• Ring abscesses
• Septal abscesses
• Fistulae
• Prosthetic dehiscence
12. • Clinical Features Clinical manifestations
– Direct
• Constitutional symptoms of infection (cytokine)
– Indirect
• Local destructive effects of infection
• Embolization – septic or bland
• Hematogenous seeding of infection
» N.B. may present as local infection or persistent fever,
metastatic abscesses may be small, miliary
• Immune response
» Immune complex or complement-mediated
Clinical Features
13. Clinical Features
• Interval between index bacteremia &
onset of sx’s usually < 2 weeks
• Systemic manifestation like any other AFIs
• Fever most common sign
• Murmur present in 80 – 85%
• Generally indication of underlying lesion
• Frequently absent in tricuspid IE
• Changing murmur
14. Modified Duke criteria
Major criteria include---- Table-I
1. Positive blood culture with typical IE microorganism, defined as one of the
following:
– Typical microorganism consistent with IE from 2 separate blood cultures, as
noted below:
• Viridans-group streptococci, or
• Streptococcus bovis including nutritional variant strains, or
• HACEK group, or
• Staphylococcus aureus, or
• Community-acquired Enterococci, in the absence of a primary focus
– Microorganisms consistent with IE from persistently positive blood cultures
defined as:
• Two positive cultures of blood samples drawn >12 hours apart, or
• All of 3 or a majority of 4 separate cultures of blood (with first and last
sample drawn 1 hour apart)
• Coxiella burnetii detected by at least one positive blood culture or
antiphase I IgG antibody titer >1:800
15. …Modified Duke criteria
2. Evidence of endocardial involvement with
positive echocardiogram defined as
– Oscillating intracardiac mass on valve or
supporting structures, in the path of regurgitant
jets, or on implanted material in the absence of an
alternative anatomic explanation, or
– Abscess, or
– New partial dehiscence of prosthetic valve or new
valvular regurgitation (worsening or changing of
preexisting murmur)
16. …Modified Duke criteria
Minor criteria include:
• Predisposing factor: known cardiac lesion, recreational drug
injection
• Fever >38°C
• Evidence of embolism: arterial emboli, pulmonary infarcts,
Janeway lesions, conjunctival hemorrhage
• Immunological problems: glomerulonephritis, Osler's nodes
• Positive blood culture (that doesn't meet a major criterion) or
serologic evidence of infection with organism consistent with
IE but not satisfying major criterion
• Positive echocardiogram (that doesn't meet a major criterion)
(this criterion has been removed from the modified Duke
criteria)
28. Imaging
• Chest x-ray -Look for multiple focal infiltrates and calcification
of heart valves
• EKG-Rarely diagnostic Look for evidence of ischemia,
conduction
delay, and arrhythmias
• Echocardiography
TTE- - First line if suspected IE
– Native valves
• Transesophageal echocardiography (TEE)
» Prosthetic valves
» Intracardiac complications
» Inadequate TTE
» Fungal or S. aureus or bacteremi
29. Goals of Therapy
1. Eradicate infection
2. Definitively treat sequelae of destructive
intra-cardiac and extra-cardiac lesions
32. Antibiotic Therapy
• Effective antimicrobial treatment should lead
to defervescence within 7 – 10 days
– Persistent fever in:
• IE due to staph, pseudomonas, culture negative
• IE with microvascular complications/major emboli
• Intracardiac/extracardiac septic complications
• Drug reaction
33.
34. Surgical Treatment of Intra-Cardiac
Complications
• Relative indications
– Perivalvular extension of infection
– Poorly responsive S. aureus NVE
– Relapse of NVE
– Culture negative NVE/PVE with persistent fever (>
10 days)
– Large (> 10mm) or hypermobile vegetation
– Endocarditis due to highly resistant enterococcus
