Infective Endocarditis

Definition

Infective endocarditis is an infection of the endocardium that typically affects one or more heart valves.

  • Acute vs subacute:
    • Acute
      • Fast progression (days – weeks)
      • High fever
      • S. Aureus
    • Subacute
      • Slow progression (weeks – months)
      • Low fever
      • Viridans strep, Enterococci, S. Aureus
Etiology
  • Most common pathogens:
    1. S. Aureus
    2. Viridans group streptococci
    3. enterococci
  • Risk factors:
    • > 60 years of age
    • Male
    • IV drug use
    • Poor dentition
  • Valve involvement order:
    1. Mitral
    2. Aortic
    3. Tricuspid
    4. Pulmonary
Clinical Features
  • Duke Criteria (Presence of 2 major OR 1 major with 3 minors OR 5 minors)
    • Major
      • 2 separate blood cultures (S. Aureus, HACEK, S. Viridans)
      • One positive culture from Coxiella Burnetii
      • Echocardiographic findings of IE
    • Minor
      • Predisposing condition
      • Fever (>38C)
      • Vascular abnormalities (emboli, septic infarctions, Janeway lesions)
      • Immunologic abnormality (glomerulonephritis, Osler’s nodes, roths sports, positive rheumatoid factor)
      • Microbiological evidence (+ve blood culture not meeting major criteria)
Investigations
  • CXR: cardiomegaly
  • Echocardiogram (best): inflamed heart muscle, dilation
  • ECG: Sinus Tachycardia, T-wave inversions, ST elevations
  • FBE
    • Elevated Troponin
    • Elevated Creatine Kinase
Management
  • Antibiotics
    • Vancomycin with:
      • Cefepime for native acute cases
      • Ampicillin-sulbactam for native subacute cases
  • Transplant in severe cases
Author