types of infective endocarditis

Last reviewed 01/2018

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

  • 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.