Infective Endocarditis
J.B. Handler, M.D.
Physician Assistant Program
University of New England
1
Abbreviations









ABE- acute bacterial
endocarditis
SBE- subacute bacterial
endocarditis
IE- infectious endocarditis
ASD- atrial septal defect
VSD- ventricular septal
defect
PDA- patent ductus
arteriosus
AoV- aortic valve
MVP- mitral valve prolapse
TEE- transesophageal
echocardiography








TTE- transthoracic
echocardiography
PCN- penicillin
HCM- hypertrophic
cardiomyopathy
AR- aortic regurgitation
MR- mitral regurgitation
TR- tricuspid regurgitation
RV- right ventricle
CABG- coronary artery
bypass graft surgery
2
Key Terms
Infective Endocarditis: Infection on a
cardiac valve or an endocardial
surface within the heart.
 Most cases are due to bacterial
infection; fungal infections much
less common.

3
Pathogenesis


In >50% of cases, underlying valve
abnormality (acquired or congenital)
provides source of turbulent blood
flow/jet effectstransient bacteremia
(from procedure or surgery)
colonizationinfection.
Normal valve endocarditisbacteremia
with virulent organism (like S aureas)
infection. Example: IV drug abuser.
4
Common Underlying Lesions


Rheumatic valve disease; bicuspid AoV;
aortic stenosis/sclerosis/regurgitation;
mitral stenosis/regurgitation/prolapse;
hypertrophic CM.
Most forms of congenital heart disease
except ASD.
5
Common Underlying Lesions

Many surgically corrected congenital
cardiac lesions except ASD, VSD and
PDA.


CABG surgery and permanent
pacemakers do not predispose to
endocarditis.
Prosthetic heart valves.
6
Bacteremia


Portals of entry: skin, upper respiratory
tract, oral cavity, GI (lower)/GU tracts.
Commonly from procedures or surgery.
Some dental work/cleaning/flossing &
related procedures; procedures and
surgeries involving upper respiratory,
lower GI & GU tracts.


Frequent exposure to random bacteremia
from frequent brushing/flossing.
Presence of indwelling catheters, esp.
central lines.
7
Organisms



S viridans, group D strep,
Enterococcus faecalis, S aureas (most
common organism).
HACEK organisms: Haemophilus,
Actinobacillus, Cardiobacterium,
Eikenella, Kingella
Prosthetic valve endocarditis:


Early (1st 2 mos): S aureas, S epidermitis,
gram negative organisms and fungi
Late: Streptococci & Staph (coag+ and -)
8
Involvement of Cardiac
Valves



Mitral and Aortic most commonly
involved.
Classic valve lesion is a vegetation:
mass of platelets, fibrin, colonies of
bacteria + few inflammatory cells; visible
on 2D echocardiography TEE>TTE.
RV endocarditis: Tricuspid ( 85% of
cases) > pulmonic valve (15%) involved
only in setting of IV drug abuse;
organism usually S aureas.
9
Endocarditis
Images.google.com
Vegetations on MV
Images.google.com
Vegetation: 2- D Echo
Images.google.com
Clinical Findings



Febrile illness often with with nonspecific symptoms at onset. Fever
usually elevated, often 38 degrees C,
night sweats, arthralgias, myalgias,
weight loss. Duration days to weeks.
Infectious emboli to brain, kidneys,
joints, skin, lungs, mensenteric
circulation & bowels: stroke, flank pain,
arthritis, cough/dyspnea, abscesses,
organ infarction, abd pain.
New or changing regurgitant heart
murmurs may be present.
13
Clinical Findings

Peripheral lesions from micro emboli:



Petechiae (palate, conjunctiva)
Subungal (“splinter”) hemorrhages
Immunologic lesions:



Osler’s nodes: painful, raised lesions of
fingers/toes
Janeway lesions: painless lesions of palms
or soles
Roth spots: exudative lesions in the retina
14
Immunologic Lesions
Osler’s Nodes
Images.google.com
Janeway Lesions
Immunologic Lesions
Roth Spots
Images.google.com
Varying Presentations


Staph aureas and other more virulent
organisms: acute course with rapidly
progressive, destructive infection
(ABE); acute febrile illness, early
embolization, valvular destruction and
insufficiency.
Viridans streptococci, enterococcus:
sub-acute course (weeks); systemic
and peripheral manifestations
predominate; valvular destruction
gradual.
17
Diagnostic Studies



Blood cultures: essential to the
diagnosis and treatment; must draw 3
sets, 1 hr apart; before considering
empiric antibiotics.
Echocardiography: TEE 90% sensitive
in localizing involved valve. TTE- 60% s.
Pathognomonic finding is a vegetation.
Leukocytosis, anemia or hematuria
depending on infecting organism,
embolization and immune response.
18
Dx of Endocarditis: Modified
Duke Criteria

Major:



2+ BC’s with typical
organism
Abnormal echo for
vegetation or similar
New regurgitant
murmur

Minor:





Predisposing condition:
valve abn; IV drug use
Fever 38 degrees
Vascular phenomenon:
systemic emboli,
infarction; cutaneous
hemorrhage
Immunologic lesion
+ BC not meeting
above criterion
19
Dx of Endocarditis: Modified
Duke Criteria

Definite Dx:
2 major criteria
 1 major +3 minor criteria
 5 minor criteria


Possible Dx:
1 major +1 minor criteria
 3 minor criteria

20
Permanent Damage

Heart: AR, MR, TR, often severe
due to destruction of valves.

Heart failure often a result of left
sided valvular regurgitation (AR,MR).
Emboli to brainstrokes
 Emboli elsewhere: kidneys, lungs,
joints, bowels, other.

21
Prevention



Procedures likely to cause transient
bacteremia can lead to endocarditis;
prophylactic Rx with antibiotics
beforehand can be protectivelimited
applications (below).
Procedures: see slide #7 above
Significant change in
recommendations made in 2007.

In past most forms of valve disease warranted
Abx prophylaxis before procedure; now very
limited.
22
Current Indications for
Antibiotic Prophylaxis






Prosthetic heart valve
Prior episode of endocarditis
Unrepaired or incompletely repaired complex
cyanotic congenital heart disease
Completely repaired cong ht disease with
prosthetic material: for 1st 6 mos. post repair
Repaired cong heart defect with residual defect
at the site of prosthetic patch/device.
Cardiac transplant patient with valvular disease
Ref: http://www.ada.org/prof/resources/topics/infective_endocarditis_guidelines.pdf
23
Antibiotic Prophylaxis

Other valvular lesions, whether
congenital or acquired, do not
require endocarditis prophylaxis
before bacteremia associated
procedures. Risk of getting
endocarditis out-weighed by risk of
side effect or reaction to the
antibiotic.
24
Antibiotic Prophylaxis

Antibiotic prophylaxis (dental work):
oral amoxicillin 2 grams 30 to 60”
before procedure. Alternatives:
cephalexin, clindamycin,
azithromycin or clarithromycin. See
current: chap 33 table 33-5.
25
Treatment of Endocarditis


Should be based on organism identified
by blood cultures.
Example- S viridans: Penicillin G 2-3
million units every 4 hours x 4 wks.


If add gentamycin 1mg/kg IV q8 hrs to PCN,
course is shortened to 2 wks.
Empiric Rx if needed while awaiting BC
results: Vancomycin + Ceftriaxone, both
IV.
26