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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.