An infection involving the endocardial surface of the heart, including valvular structures, chorda tendinae, sites of septal defects and mural endocardium

Causes

• Staphylococcus aureus (most common cause)
  • particularly common in acute presentation and IVDUs
• Streptococcus viridans -
  • Most common cause in developing countries
  • patients with a history of cardiac disease
  • patients with very poor dental heigene
• coagulase-negative Staphylococci such as Staphylococcus epidermidis
  • commonly colonize indwelling lines and are the most cause of endocarditis in patients following prosthetic valve surgery, usually the result of perioperative contamination.
• Streptococcus bovis - the subtype  is most linked with colorectal cancer
• non-infective
  • systemic lupus erythematosus (Libman-Sacks)
  • malignancy: marantic endocarditis

Culture negative causes

• prior antibiotic therapy

• Coxiella burnetii

• Bartonella

• Brucella

• HACEK: )

  Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella

Risk factors:

The strongest risk factor for developing infective endocarditis is a previous episode of endocarditis. The following types of patients are affected:

• previously normal valves (50%, typically acute presentation)
  • the mitral valve is most commonly affected
• rheumatic valve disease (30%)