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Cardiac Infections

Endocarditis, Rheumatic Fever, Myocarditis, and Kawasaki Disease

Infective Endocarditis: Etiologic Agents

Streptococci

· Viridans accounts for more than 50% of streptococci causing infective endocarditis, including nutritionally variant S defectivus and S adjacens

Enterococci ~ 5%S pneumoniae, beta streptococci - rare

Staphylococci: especially post-op or in normal hearts

S aureus ~ 10-15%

Coagulase-negative ~ 10%

 HACEK group: 5-10%

· H aphrophilus Actinobacillus, Cardiobacterium hominis, Eikenella Corrodens, Kingella kingae

· Fastidious Gram-negative coccobacilli

Others -5%

· Fungi especially Candida

· Aerobic gram negatives: neonates; line-associated infective

· Coxiella burnetii

Infective Endocarditis - Pathogenesis cardiac infections, endocarditis, valve infection

Factors Associated with

· Areas of turbulent flow (jet effect, eddies)

· Endothelial disruption

· Sterile fibrin-platelet thrombus development on the abnormal surface

· Entrapment of bacteria from "stray bacteremia" leads to focus of infection

Infective Endocarditis - Clinical Features

Acute Presentation

· High fever, toxicity

Infective Endocarditis - Evaluation

Three or more blood cultures (separate venipunctures) before therapy

Trans-thoracic echocardiography (-60% sensitive)

Role of trans-esophageal echocardiography is evolving

Infective Endocarditis - Diagnostic Criteria

Duke Criteria

· Incorporate clinical and echocardiographic features

· Major and Minor Criteria

- Definite Infective Endocarditis: Pathologic evidence of IE, or two majors, or one major and 3 minors, or 5 minors

- Possible Infective Endocarditis: Consistent with IE, not definite or rejected

- Rejected Infective Endocarditis: Firm alternate diagnosis, or resolution of illness or absence of evidence of IE at surgery or autopsy after <4 days of antibiotics

- Major Criteria

· Positive blood cultures

* Typical

Infective Endocarditis: Treatment

_ Prolonged, parenteral, bactericidal antibiotics

_ Highly sensitive streptococci (MIC<0.1 mcg/mL)

· Penicillin G or Ceftriaxone 4 weeks

· Penicillin G and Gentamicin 2 weeks

· Vancomycin (for Pen-allergic) 4 weeks

_ Relatively resistant streptococci (MIC >0.1, < 0.5)

· Penicillin G 4 weeks and Gentamicin 2 weeks

· Vancomycin (for Pen-allergic) 4 weeks

_ Enterococci

· Pen G or Ampicillin and Gentamicin 4-6 weeks

· Vancomycin (for Pen-allergic) 4-6 weeks

and Gentamicin