Types of infective endocarditis

Traditionally, infective endocarditis has been classified into two broad categories according to the pathogenic organism and the clinical presentation: (1)

- acute:

• most often caused by Staphylococcus aureus
• equally prevalent on normal and abnormal valves
• it is rare
  
  

• subacute:
  • most often caused by Streptococcus viridans
  • usually
  • affects abnormal valves
  • more common

Two specific forms of endocarditis are the infections associated with prosthetic heart valves and intravenous drug abuse:

• prosthetic:
  • follows valve replacement
  • may present early, within 60 days of valve replacement or late
    
    
• right sided endocarditis in intravenous drug abuse:
  • accounts for 5% of cases
  • tricuspid valve invariably affected
  • usually presents acutely in I.V. drug abusers or the immunosuppressed

95% of cases of infective endocarditis effect the left side of the heart, with the mitral and aortic valves affected equally.

1. Holland TL et al. Infective endocarditis. Nat Rev Dis Primers 2016. Available from: https://pubmed.ncbi.nlm.nih.gov/27582414/