Infective Endocarditis Flashcards
What is bacteraemia?
The presence of bacteria in the bloodstream. Potentially life-threatening event the patient can get septic shock
What is blood’s normal bacterial state?
Blood is sterile so often there will be bacterial contamination from the blood collection rather than blood that was in the sample - it is important you therefore know what the types of bacteria indicate contamination or blood infection
What are the organisms which can cause infection in cardiac implantable electronic devices?
Skin organisms such as - staphylococcus aureus staphylococcus epidermidis corynebacterium sp. propionibacterium acnes
Biofilm forms
Anatomic location of infection
Box, leads. Endocardium
What are the risk factors of ICED infections?
Pre procedure prophylaxis Complexity of procedure Temporary pacer use Type of device Number of revisions / reinterventions Fever within 24 hours Heart failure, renal failure Haematoma post procedure
What organism is most commonly responsible for septic shock?
Staphylococcus aureus
What is an ICED?
Implantable cardiac electronic device
What is infective endocarditis?
infection of the endothelium of the heart valves. Can be acute or subacute, it is life threatening up to 25% mortality
What is the pathogenesis of endocarditis?
The heart valve is damaged
there is turbulent blood flow over roughened endothelium
Platelets / fibrin deposited
Bacteraemia (may be very transient) e.g. from dental treatment
organisms settle in fibrin/platelet thrombi becoming a microbial vegetation
Infected vegetations are friable and break off, becoming lodged in the next capillary bed they encounter causing abscesses or haemorrhage - may be fatal
Usually mitral and aortic valves which are affected
What are the organisms which cause of native valve endocarditis?
Staphylococcus aureus (patient is very unwell)
Viridans group streptococci (slow burner)
enterococcus sp.
Staphylococcus epidermidis (has some metal or plastic implanted)
What are the unusual organisms which can cause endocarditis?
look for these if no organisms are seen in the blood culture but there is vegetation on the echo or the history really suggest endocarditis
What is Modified Duke criteria?
…
What are the symptoms of subacute endocarditis?
Fever malaise Weight loss Tiredness Breathlessness
What are the signs of subacute endocarditis?
Fever New or changing heart murmur finger clubbing splinter haemorrhages splenomegaly Roth spots, Janeway lesions, Osler nodes microscopic haematuria
What group do alpha haemolytic strep belong to?
The viridans group
If you’re considering endocarditis what are the investigations you should carry out?
Blood cultures
transthoracic echo or transoesophageal echo
