lecture 10 - infective endocarditis Flashcards
What is infective endocarditis?
Infection of the heart valves and mural endocardium
What class of infective endocarditis (IE) targets previously healthy valves?
Acute
What class of infective endocarditis (IE) targets previously damaged valves?
Subacute
What bacteria most commonly causes acute endocarditis?
Staphylococcus aureus
What is the difference between bacteraemia and septicaemia?
Bacteraemia is the presence of bacteria in the blood, which may be transient and not cause disease. Septicaemia is the pathological inflammatory response to bacteraemia
What is the key diagnostic lab test for septicaemia?
Blood cultures
What are the features of valves infected by infective endocarditis?
Presence of vegetations - aggregations of thombi and microbes
What bacteria is the most common cause of endocarditis in patients with prosthetic valves/devices implanted?
Staphylococcus epidermidis
What bacteria is the most common cause of subacute endocarditis?
Streptococcus viridans
How is the endocardium initially infected in infective endocarditis?
Via bacteraemia - spread of bacteria in the blood
What are the symptoms of infective endocarditis?
PUO (pyrexia of unknown origin), new murmur, non-specific general symptoms
What is the pathogenesis of vegetation formation in infective endocarditis?
Bacteria bind to and cause platelet activation and aggregation
Why does pre-existing valve damage increase the risk of developing infective endocarditis?
Damaged valves may have weak epithelium and collagen may be exposed, increasing platelet and coagulation activation
What is the key complication of infective endocarditis?
Septic embolism & infarct
What criteria is used to diagnose Infective Endocarditis?
Duke Criteria
