Course Outlines:

  • Definition
  • Classification
  • Aetiology
  • Pathogenesis
  • Morphology
  • Clinical Features
  • Treatment
  • Prevention


  • Infective endorcarditis is a serious heart infection which is caused by inversions of heart valves or heart endocardium by microorganisms.
  • This leads to formation of abnormal tissues consisting of thrombotic debris, microorganisms which come from destruction of heart tissues.


It is classified into two based on clinical severity which is determined by the virulence of the causative organinisms and whether the valves have been previously normal or deformed.

  1. Acute endorcarditis
  2. Subacute endorcarditis


  • This is caused by inversions of heart valves that have been previously normal and is caused by more virulent organisms.
  • It is severe and difficult to be treated with antibiotics.


  • It is caused by colonization or inversions of already deformed heart valves by less virulent organisms.
  • It can proceed to periods of weeks or months and can be treated with antibiotics.


  • Acute endocarditis which results from infections of previously normal heart valves is caused mostly by more virulent Staphylococcus aureus.
  • Prosthetic heart endocarditis is usually caused by coagulase negative Staphylococcus species ( eg. Staphylococcus epidermidis).
  • Staphylococcus aureus is commonly implicated in intravenous drug abusers.
  • Acute is seen in 10% to 20% of the cases.
  • Subacute endocarditis which results from infections of previously deformed heart valves is mostly caused by less virulent organisms like Streptococcus viridians.
  • Subacute results in 50% to 60% of the cases.
  • About 10% to 15% the causes are unknown.
  • Other causes are known as HACEK. These include: Hemophilus, Actinobacillus, Cardiobacterium, Eikenella and Kingella which are commensals of oral cavity.
  • Gram negative bacillus and fungi are also implicated.


  • Organisms gain access to bloodstream from clinical procedures either from oral cavities or from intravenous access.
  • From blood the organisms invade the heart tissues. Organism like Staph. aureus has direct access to heart valves and endocardium resulting in inflammation and aggressive tissue destruction.
  • Embolization of vegetative materials may occur causing complications like ischaemic stroke, meningitis, aneurysm, cerebral hemorrhage and brain abcess.


  • The hallmark of the morphology of infective endocarditis is formation of bulky and potentially destructive vegetative materials containing fibrin, microorganisms, inflammatory cells on heart valves.
  • Mitral and aortic valves are mostly affected. But valves of right heart can also be involved.
  • Formation of ring abscess within the endocardium caused by the vegetation.
  • Formatiom of emboli which may cause septic cardiac infarcts or mycotic aneurysm.


  • Early symptoms of Infective endocarditis include: fever, chills, weakness, lassitude.
  • Murmurs are present in 90% of the cases
  • Early treatment may eliminate late symptoms which may result from embolism such as lesions on palm or soles, retinal hemorrhage, subcutaneous nodules in the pulp of digits.


  • Subacute endocarditis can be treated with antibiotics. Your doctor should guide you on the proper drugs to take.
  • Acute endocarditis is hard to be treated and this calls to give attention to the preventive measures below.


  • Practicing total hygiene(especially oral hygiene) is the best measure compared to taking preventive drugs before surgery.
  • Body hygiene helps to reduce potentially harmful micro flora from skin and oral cavities.
  • Proper procedures should be followed in clinical practice to avoid transmission of this infection

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By Livinus Uguru

The author and founder of Livinus Uguru's Blog Livinus Uguru is a renowned passionate blogger, digital marketer, content creator and medical practitioner. He enjoys sharing knowledge and experiences to the benefit of general public, and has written many news and articles published in different media and online platforms. Hope you enjoy reading this blog posts?

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