INFECTIVE ENDOCARDITISMOKGWANE EUTLWETSE

4TH YEAR MED14/07/2011

UWI, BAHAMAS CAMPUS

DEFINITIONInfective Endocarditis (IE) is a microbial

infection of the endocardial (endothelial) surface of the heart.

The vegetation is a variably sized amorphous mass of platelets and fibrin in which abundant micro-organisms and scant inflammatory cells are enmeshed.

Braunwald – Heart Disease

CAUSES OF IE

-

PREDISPOSING CONDITIONS

CHILDREN(%)(neonates)

CHILDREN(%)(2mths-15yr)

ADULTS(%)(15-60yr)

ADULTS (%)>60yr

RHDCHDMVPDHDParenteral Drug AbuseOtherNone

MICRBIOLOGYStreptococciEnterococciS. aureusCoagulase ve StaphylococciGNBFungiPolymicrobial

28

72

15-20

50-5010

10104

2-175-9015-95

2-5

40-504255

51

25-3010-2010-30RARE15-35

10-1525-45

45-655-830-403-5

4-811

82103010

1025-40

30-451525-305-8

5RARERARE

RISK FACTORS FOR SPECIFIC PATHOGENS THAT CAUSE IE

Dental procedures, poor dental hygiene - viridans streptococci,nutritionally variant streptococci, HACEK• Prosthetic valves – Early: coagulase negative staphylococci, S. aureus – Late: coagulase negative staphylococci, viridans

streptococci• Gastrointestinal or genitourinary procedures - enterococci or

S. bovis (colon carcinoma)• Nosocomial - S. aureus (including MRSA), Gram negatives,Candida species

Brouqui and Raoult, Clin Microbiol Rev, 2001

PATHOGENESISEndothelium resistant to bacteria and thrombus formation

Endothelial injury and hypercoagulable state- high velocity jets, obstructive lesions, aberrant flows, direct invasion by virulent pathogens can lead to non-bacterial thrombotic embolism(NBTE)

Mitral regurgitation, Aortic stenosis, Aortic regurgitation, Ventricular Septal Defect, complex congenital heart disease can create

NBTEMost bacteria find NBTE a convenient site or nidus for adherenceVirulent organisms- Staph. aureus, Strep. pyogenes, Strep. pneumoniae have

surface molecules which allow them to adhere to intact endothelium and to exposed sub-endothelial tissues

If the adhering bacteria are able to survive serum cidal activity, peptides, complement , antibody etc., they multiply – infective vegetation.

PATHOPHYSIOLOGY

The clinical manifestation IE result from:

1. The local destructive effects of intracardial infection;2. The embolization of septic fragments of vegetations

to distant sites, resulting in infarction or infection;3. The hematogenous seeding of remote sites during

continuous bacteremia and4. An antibody response to the infecting organism with

subsequent tissue injury due to deposition of preformed immune complexes.

CLINICAL MANIFESTATIONSYMPTOMS PERCENT SIGNS PERCENT

FeverChillsSweatsAnorexiaWeight lossMalaiseDyspneaCoughStrokeheadacheNausea/vomitingmyalgia/arthralgiaChest painAbdominal painBack painconfusion

80-9542-752525-5525-3525-4020-402513-2015-4015-2015-308-355-157-1010-20

FeverMurmurChanging/new murmurNeurological abnormalitiesEmbolic eventSplenomegalyClubbingPeripheral manifestationOsler’s nodesSplinter hemorrhagePetechiaeJaneway’s lesionsRetinal lesion

80-9080-9510-40

30-40

20-4015-5010-2010-20

7-105-15

10-406-104-10

CLINICAL MANIFESTIONACUTE COURSE SUBACUTE COURSE

Rapid onsetHigh fever >39o C30-40% may not have a murmurRapid deteriorationDeath occurs with days to weeks in 50 -60 % of patientsLager vegetations therefore embolic complications more commonHigh virulence organisms eg.Strep.pyogenes, Staph. aureus, Staph. lugdunensis, Strep. pnuemoniae, Enterococcus.

Insidious onsetLow grade feverHave cardiac abnormalityProgressive valvular incompetenceLess fatal compared to acute IESmaller vegetations with less embolic complicationsLess virulence organisms eg. Strep.viridans, COGNS, Staph.aureus, HACEK group, Bartonella, Coxiella burnetiiHistory of illicit drugs

DIFFERENTIAL DIAGNOSIS Endocarditis Systemic Lupus Erythematosus Cardiac Neoplasms, Primary Antiphospholipid Syndrome Reactive Arthritis Lyme disease

DIAGNOSIS OF IEPathological criteria:Microorganisms: demonstrated by culture or histology

in a vegetation, or in a vegetation that has embolized, or in an intracardiac abscess, or

Pathological lesions: vegetation or intracardiac abscess present, confirmed by histology showing active endocarditis

Clinical criteria:Two major criteria, or One major and three minor

criteria, or Five minor criteria.

DIAGNOSIS OF IEMAJOR CRITERIA

Positive blood cultureTypical microorganism for infective endocarditis from two separate blood cultures Viridans streptococci, Streptococcus bovis, HACEK group orCommunity-acquired Staphylococcus aureus or enterococci in the absence of a primary

focus, orPersistently positive blood culture, defined as recovery of a microorganism consistent

with infective endocarditis from:Blood cultures drawn more than 12 hr apart, orAll of three or a majority of four or more separate blood cultures, with first and last

drawn at least 1 hr apartEvidence of endocardial involvement

Positive echocardiogramOscillating intracardiac mass, on valve or supporting structures, or in the path of

regurgitant jets, or on implanted material, in the absence of an alternative anatomical explanation, or Abscess, or New partial dehiscence of prosthetic valve, or New valvular regurgitation (increase or change in preexisting murmur not sufficient)

DIAGNOSIS OF IEMINOR CRITERIA

Predisposition: predisposing heart condition or intravenous drug use Fever ,38.0°C (100.4°F) Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic

aneurysm, intracranial hemorrhage, conjunctival hemorrhages, Janeway's lesions Immunological phenomena: glomerulonephritis, Osler's nodes, Roth's spots,

rheumatoid factor Microbiological evidence: positive blood culture but not meeting major criterion

as noted previously or serologic evidence of active infection with organism consistent with infective endocarditis

Echocardiogram: consistent with infective endocarditis but not meeting major criterion

Adapted from Durack DT, Lukes AS, Bright DK: New criteria for diagnosis of infective endocarditis: Utilization of specific echocardiographic findings. Am J Med

96:200, 1994.

DIAGNOSIS OF IE

OTHER TESTS

ECHOCARDIOLOGY Transthoracic Echocardiology(TTE) 65% sensitive Transoesaphageal Echocardiology(TEE) >90% sensitive, 6 – 18%

false negatives Repeat in 7 – 10 days

CBCSed. RateC Reactive Protein Immune Complexes

TREATMENTANTIBIOTICS Ideal therapy includes a cell wall-active agent plus an effective

aminoglycoside to achieve bactericidal synergy. Bactericidal, prolonged administration 4 – 8 weeks Given IV Knowledge of MIC of the pathogen is important.

Strep.viridans (pen.sensitive): PenG 2-3 mU q 4hrly - 4weeks or Ceftriaxone 2 g/d - 4weeks or Vancomycin 15mg/kg q 12 hrly - 4weeks

Pen G 2-3 Mu q 4 hrly - 2weeks plus

Gentamicin 1mg/kg q 8hrly – 2weeks.

TREATMENT- ANTIBIOTICS

Streptococci (relatively resistant- mic. > 0.01)

PenG 4 mU q 4 hrly IV -4weeks or Ceftriaxone 2g/d IV – 4weeks plus Gentamicin 1mg/kg q 8hrly IV -2weeks or Vancomycin 15mg/kg q 12 IV hrly – 4 weeks

Streptococci (moderately resistant) Gemella, nut.variants

Pen G 4-5 mU q 4hrly IV -6 weeks or Ceftriaxone 2g/d IV – 6weeks plus Gentamicin 1mg/kg q 8hrly IV – 6weeks

TREATMENT- ANTIBIOTICSEnterococci: Pen G 4-5 mU q 4hrly IV - 4-6weeks or

Amp 2g q 4hrly IV- 4 -6weeks or Vancomycin 15mg/Kg q 12 hrly IV - 4– 6weeks

plus Gentamicin 1mg/kg q8hrly IV -4-6weeks.

Staphylococci (Methicillin Sensitive):

Nafcillin/Oxacillin 2gq4hrly IV 4-6 wks plus Gentamicin 1mg/Kg q 8 hrlyIV 3-5 days or Ceftriaxone 2g /d IV 4-6 weeks or Vancomycin 15mg/Kg q 12hrly IV 4-6wks

TREATMENT- ANTIBIOTICS

Staphylococci (Methicillin Resistant):

Vancomycin 15mg/Kg q 12hrly IV 4-6wks

Staphylococci (Prosthetic Valve) (Methicillin Sensitive):

Nafcillin/Oxacillin 2g q 4hrly IV 6-8wks plus Gentamicin 1mg/Kg q 8 hrly IV – 2wks plus Rifampin 300mg PO q 8hrly - 6-8wks

Staphylococci (Prosthetic Valve) (Methicillin Resistant):

Vancomycin 15mg/Kg q 12hrly IV – 6-8wks plus Gentamicin 1mg/Kg q 8hrly IV 2wks plus Rifampin 300 mg PO q 8hrly 6-8wks

TREATMENT-ANTIBIOTICS

HACEK Group(Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella):

Ceftriaxone 2g /d IV 4wks or Ampicillin/Sulbactam 3g q 6hrly 4wks

Rosendorff- Essential Cardiology

TREATMENTSURGICAL THERAPY

Moderate to severe congestive heart failure due to valve dysfunction

Partially dehisced prosthetic valve

Persistent bacteremia despite optimal antibiotic therapy

In the absence of effective antibiotic therapy

Recurrent prosthetic valve endocarditis

Prevent septic emboli

PROPHYLAXISHigh risk patients only Prosthetic valves Prior endocarditis Congenital Cyanotic Heart Disease Up to Six months after repair of Congenital Heart Disease Post cardiac transplantation

Amoxicillin 2g po 1 hr before procedureAmpicillin 2g IV 1hr before procedureAzithromycin 500mg po 1 hr before procedureCephalexin 2g po 1 hr before procedureClindamycin 600mg po 1hr before procedure Ceftriaxone 1g IV 1hour before surgeryClindamycin 600mg IV 1hour before procedure

REFERENCE1. Braunwald: Heart Disease: A Textbook of

Cardiovascular Medicine, 6th ed: Copyright © 2001 W. B. Saunders Company

2. Hugh D. A.: et al: Moss and Adams' Heart Disease in Infants, Children, and Adolescents Including the Fetus and Young Adult 6th ed (November 2000)

3. Robbins et al: Pathologic Basis of Disease: 6th ed: Copyright © 1999 W.B. Saunders Company

4 . Rosendorff C: Essential Cardiology Principles and Practices: 2nd ed: Copyright © 2005 Humana Press Inc.

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