1 infective endocarditis j.b. handler, m.d. physician assistant program university of new england
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Infective Endocarditis
J.B. Handler, M.D.Physician Assistant ProgramUniversity of New England
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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
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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.
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Pathogenesis In >50% of cases, underlying valve
abnormality (acquired or congenital) provides source of turbulent blood flow/jet effectstransient bacteremia (from procedure or surgery) colonizationinfection.
Normal valve endocarditisbacteremia with virulent organism (like S aureas) infection. Example: IV drug abuser.
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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.
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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.
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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.
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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 -)
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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.
Endocarditis
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Vegetations on MV
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Vegetation: 2- D Echo
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Clinical Findings Febrile illness often with with non- specific
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.
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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
Immunologic Lesions
Osler’s Nodes Janeway Lesions
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Immunologic Lesions
Roth Spots
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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.
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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.
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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
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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
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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 brainstrokes Emboli elsewhere: kidneys, lungs,
joints, bowels, other.
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Prevention Procedures likely to cause transient
bacteremia can lead to endocarditis; prophylactic Rx with antibiotics beforehand can be protectivelimited 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.
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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
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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.
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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.
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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.