This document provides an overview of infective endocarditis including its classification, etiology, pathogenesis, clinical manifestations, diagnostic criteria, and management. It discusses the different types of infective endocarditis such as acute versus subacute and native versus prosthetic valve. Common causative organisms and their antibiotic treatment durations are outlined. The modified Duke criteria for diagnosis is explained. Indications for surgery and timing of surgical intervention are briefly covered.
3. INTRODUCTION
What is infective endocarditis?
• infection of a native or prosthetic heart valve, the
endocardial surface, or an indwelling cardiac device
What is infective endarteritis?
• arteriovenous shunts, arterio-arterial shunts (patent
ductus arteriosus), or a coarctation of the aorta
What is a vegetation?
• is a mass of platelets, fibrin, microcolonies of
microorganisms, and scant inflammatory cells
5. Classification
• Acute endocarditis:
– Toxic
– Develops within few days
– Valvular destruction and embolic manifestation
– Most commonly by Staph aureus
• Subacute endocarditis:
– Develops in weeks to months
– More associated with immunologic phenomena
– Mostly caused by streptococci and others
7. Etiology/Epidemiology
• Health care associated NVE S. aureus, CoNS,enterococci
( 55% nosocomial onset, 45% community onset)
• PVE within 2 months of surgery nosocomial
• 68 – 85% of CoNS causing IE resistant to methicillin
• IVDU related IE most common S.aureus
• Polymicrobial endocarditis IVDU
• Negative culture 5 – 15% (1/3 to ½ due to prior antibiotics)
8. High velocity jet striking endothelium
Flow from high to low pressure chamber
Flow across a narrow orifice at high velocity
Malignancy
SLE
Antiphospholipid antibody syndrome
DIC
Endothelial
injury
Hypercoagulable state
NBTE (sterile
platelet fibrin )
+
Bacteremia
Bacteria adhere to damaged endothelium and/or sterile platelet-fibrin nidus
Bacteria multiply
Further platelet and fibrin binding
Local tissue
destruction
Embolization
Hematogenous
spread
Antibody
response
Growth of vegetation
P
A
T
H
O
G
E
N
E
S
I
S
9. • Marantic endocarditis - uninfected vegetations seen in
patients with malignancy and chronic diseases
• Libman sacks endocarditis – bland vegetations in SLE
22. MODIFIED DUKE CRITERIA- MAJOR CRITERIA
1. Positive blood culture
Typical microorganisms for IE from
2 separate blood cultures
Or
Persistently positive blood culture,
defined as recovery of a
microorganism consistent with
infective endocarditis from:
Blood cultures drawn >12 h
apart; or
All of 3 or a majority of ≥4
separate blood cultures, with first
and last drawn at least 1 h apart
Or
Single positive blood culture for
Coxiella burnetii or phase I IgG
antibody titer of >1:800
2. Evidence of Endocardial
involvement
Positive echocardiogram
Oscillating intracardiac mass on
valve or supporting structures or in
the path of regurgitant jets or in
implanted material, in the absence
of an alternative anatomic
explanation, or
Abscess, or
New partial dehiscence of
prosthetic valve,
Or
New valvular regurgitation
(increase or change in preexisting
murmur not sufficient)
23. MODIFIED DUKE CRITERIA- MINOR CRITERIA
1. Predisposition:
predisposing heart conditions
or injection drug use
2. Fever ≥38.0°C (≥100.4°F)
3. Vascular phenomena:
– Major arterial emboli
– Septic pulmonary infarcts
– Mycotic aneurysm
– Intracranial hemorrhage
– Conjunctival hemorrhages
– Janeway lesions
4. Immunologic phenomena:
– Glomerulonephritis
– Osler’s nodes
– Roth’s spots
– Rheumatoid factor
5. Microbiologic evidence:
– positive blood culture but
not meeting major criterion
– or serologic evidence of
active infection with an
organism consistent with
infective endocarditiS
24. DEFINITE INFECTIVE ENDOCARDITIS
• Pathologic criteria
Microorganisms demonstrated by
results of cultures or histologic
examination of a vegetation, a
vegetation that has embolized, or
an intracardiac abscess specimen;
or
Pathologic lesions; vegetation, or
intracardiac abscess confirmed by
results of histologic examination
showing active endocarditis
• Clinical criteria
2 major criteria, or
1 major criterion and 3 minor
criteria, or
5 minor criteria
• Possible Infective
Endocarditis
1 major criterion and 1 minor
criterion, or
3 minor criteria
25. • Rejected Diagnosis of Infective Endocarditis
Firm alternate diagnosis explaining evidence of suspected IE,
or
Resolution of IE syndrome with antibiotic therapy for ≤4 days,
or
No evidence of IE at surgery or autopsy, on antibiotic therapy
for ≤4 days, or
Does not meet criteria for possible IE
29. Electrocardiography
– to assess for conduction abnormalities (such as varying and
progressive degrees of atrioventricular [AV] block) suggestive
of abscess formation, which are particularly associated with
aortic valve endocarditis
– Ischemic/infarct changes suggestive of coronary emboli
CXR
– Evidence of HF (pulmonary edema)
– Septic emboli, particularly in IV drug users with suspected
right-sided endocarditis
30. Transthoracic Echo (tte)
• TTE may detect valvular vegetations with or without positive blood
cultures
• It is used to characterize the hemodynamic severity of valvular
lesions in known IE
• It can also assess for complications of IE (e.g. abscesses, perforation,
and shunts)
• TTE can be used to reassess high-risk patients (e.g., those with a
virulent organism, clinical deterioration, persistent or recurrent
fever, new murmur, or persistent bacteremia)
32. Transesophageal Echo
(TEE)
• Assess the severity of valvular lesions in symptomatic patients with
IE if TTE is nondiagnostic
• Diagnose IE in patients with valvular heart disease and positive
blood cultures if TTE is nondiagnostic
• Diagnose complications of IE with potential impact on prognosis and
management (e.g. abscesses, perforation, and shunts)
• First-line diagnostic study to diagnose PVE and to assess for
complications
33. TREATMENT
ORGANISM
• Streptococi
• Penicillin sensitive
• Relatively penicillin
resistant
• Moderately
penicillin resistant
DRUG ( DURATION)
• Penicillin G x 4 weeks
• Ceftriaxone x 4 weeks
• Vancomycin x 4 weeks
• Penicillin G + Gentamicin x 2 weeks
• Penicillin G or Ceftriaxone x 4 weeks
plus Gentamicin x 2 weeks
• Vancomycin x 4 weeks
• Penicillin or Ceftriaxone x 6 weeks
plus gentamicin x 6 weeks
• Vancomycin x 4 weeks
34. TREATMENT
ORGANISM
• Enterococci
DRUG ( DURATION)
• Penicillin G + Gentamicin x 4 - 6 weeks
• Ampicillin + gentamicin x 4 - 6 weeks
• Vancomycin + gentamicin x 4 - 6 weeks
• Ampicillin + ceftriaxone x 6 weeks
35. TREATMENT
ORGANISM DRUG ( DURATION)
• Staphylococi
• Native valve
MSSA Nafcillin, Oxacillin or Flucloxacillin x 4 – 6 weeks
Or Cefazolin x 4 – 6 weeks
Or Vancomycin x 4 – 6 weeks
MRSA Vancomycin x 4 – 6 weeks
• Prosthetic valve
MSSA Nafcillin, Oxacillin or Flucloxacillin x 6 – 8 weeks
plus Gentamicin x 2 weeks
plus Rifampicin x 6 – 8 weeks
MRSA Vancomycin x 6 – 8 weeks
plus Gentamicin x 2 weeks
plus Rifampicin x 6 – 8 weeks
36. Treatment
ORGANISM
• Coxiella burnetii
• Bartonella spp.
DRUG ( DURATION)
• Doxycycline + x 18 months (NVE)
Hydroxychloroquine x 24 months (PVE)
• Ceftriaxone or Ampicillin x 6 weeks
or doxycycline
plus Gentamicin x 3 weeks
37. DRUG DOSAGE
Penicillin G 4 mU iv q4h
Ceftriaxone 2 g iv qd
Vancomycin 15mg/kg iv q12h
Gentamycin 3 mg/kg iv or im single dose
Or 1 mg/kg iv q8h
Ampicillin 2 g iv q4h
Nafcillin/Oxacillin 2 g iv q4h
/Flucloxacillin
Cefazolin 2 g iv q8h
Rifampicin 300 mg PO q8h
