ENDOCARDITIS (INFECTIVE)
Infective endocarditis = infection to the endocardium of the heart (innermost lining).
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Presentation
There are two disease courses: acute and rapidly progressive, and subacute, chronic low grade infection.
§ Fever (90%)
§ Malaise, lethargy
§ Anorexia, weight loss
§ Abdominal pain ® splenic abscess
§ Haematuria ® renal embolic phenomenon
§ Cardiac symptoms ® SOB, chest pain, palpitations
§ Cardiac murmur (85%) ® pansystolic murmur of mitral regurgitation or early diastolic murmur of aortic regurgitation
§ Features of heart failure ® raised JVP, bilateral crackles
§ Splinter haemorrhages ® thin, red to reddish-brown lines under nails (microemboli)
§ Petechiae (20-40%) ® skin and mucous membranes
§ Janeway lesions ® nontender erythematous macules on palms and soles (microabscesses)
o Acute > subacute
§ Osler nodes ® tender subcutaneous violaceous nodules mostly on pads of fingers and toes (immune complex
deposition)
o Subacute > acute
§ Roth spots ® exudative, oedematous haemorrhagic lesions of retina with pale centre (immune complex deposition)
o Subacute > acute
§ Splenomegaly ® splenic abscess formation
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Pathophysiology
Infection occurring to the endocardium of the heart.
§ The majority of cases involve Streptococcal and Staphylococcal species
o Staphylococcus
§ Staphylococcus aureus ® both acute and subacute IE, may lead to significant valve destruction
§ Coagulase negative Staphyloccus (CoNS) ® subacute, commonly associated with prosthetic devices
o Streptococcal
§ Alpha-haemolytic ® common in subacute due to poor dentition, 50-60% of cases, e.g. Viridans
streptococci
§ Beta-haemolytic
• Group A ® more virulent course, similar to S. aureus
• Group B ® acute course, typically seen in pregnancy
• Group D ® Streptococcus gallolyticus (S. bovis), classic cause of subacute, strong association
with colorectal cancer
• Other ® group C, G
o Enterococcal
§ Enterococcus faecalis ® most common
o HACEK organisms
§ 5% of subacute
§ E.g. Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis,
Eikenella corrodens, Kingella kingae
o Fungal
§ Poor prognosis (50% mortality)
§ Candida species ® C. albicans, C. stellatoidea
§ Aspergillus species
§ Mostly caused by bacterial infections entering the bloodstream and depositing on the endocardium
§ Causes can be divided into:
o Native valve endocarditis ® normal valve, no previous intervention
§ Commonly due to underlying rheumatic heart disease, congenital heart disease or structural heart
disease
§ Presents with subacute course
§ Streptococcal species (alpha-haemolytic, S. bovis) and Enterococci ® 70% cases
Infective endocarditis = infection to the endocardium of the heart (innermost lining).
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Presentation
There are two disease courses: acute and rapidly progressive, and subacute, chronic low grade infection.
§ Fever (90%)
§ Malaise, lethargy
§ Anorexia, weight loss
§ Abdominal pain ® splenic abscess
§ Haematuria ® renal embolic phenomenon
§ Cardiac symptoms ® SOB, chest pain, palpitations
§ Cardiac murmur (85%) ® pansystolic murmur of mitral regurgitation or early diastolic murmur of aortic regurgitation
§ Features of heart failure ® raised JVP, bilateral crackles
§ Splinter haemorrhages ® thin, red to reddish-brown lines under nails (microemboli)
§ Petechiae (20-40%) ® skin and mucous membranes
§ Janeway lesions ® nontender erythematous macules on palms and soles (microabscesses)
o Acute > subacute
§ Osler nodes ® tender subcutaneous violaceous nodules mostly on pads of fingers and toes (immune complex
deposition)
o Subacute > acute
§ Roth spots ® exudative, oedematous haemorrhagic lesions of retina with pale centre (immune complex deposition)
o Subacute > acute
§ Splenomegaly ® splenic abscess formation
-----------------------------------------------------------------------------------------------------------------------------------------------------
Pathophysiology
Infection occurring to the endocardium of the heart.
§ The majority of cases involve Streptococcal and Staphylococcal species
o Staphylococcus
§ Staphylococcus aureus ® both acute and subacute IE, may lead to significant valve destruction
§ Coagulase negative Staphyloccus (CoNS) ® subacute, commonly associated with prosthetic devices
o Streptococcal
§ Alpha-haemolytic ® common in subacute due to poor dentition, 50-60% of cases, e.g. Viridans
streptococci
§ Beta-haemolytic
• Group A ® more virulent course, similar to S. aureus
• Group B ® acute course, typically seen in pregnancy
• Group D ® Streptococcus gallolyticus (S. bovis), classic cause of subacute, strong association
with colorectal cancer
• Other ® group C, G
o Enterococcal
§ Enterococcus faecalis ® most common
o HACEK organisms
§ 5% of subacute
§ E.g. Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis,
Eikenella corrodens, Kingella kingae
o Fungal
§ Poor prognosis (50% mortality)
§ Candida species ® C. albicans, C. stellatoidea
§ Aspergillus species
§ Mostly caused by bacterial infections entering the bloodstream and depositing on the endocardium
§ Causes can be divided into:
o Native valve endocarditis ® normal valve, no previous intervention
§ Commonly due to underlying rheumatic heart disease, congenital heart disease or structural heart
disease
§ Presents with subacute course
§ Streptococcal species (alpha-haemolytic, S. bovis) and Enterococci ® 70% cases
