Endocarditis, Myocarditis and Pericarditis Flashcards
What is bacteraemia?
The presence of viable bacteria in the blood stream
What is the old name for bacteraemia?
Septicaemia
What is endocarditis?
The endovascular inflammation of cardiovascular structures, usually involving the cardiac valves
What is myocarditis?
An inflammatory process leading to acute, subacute or chronic injury to the myocardium
What is pericarditis?
Inflammation of the pericardium
What are some forms of testing that can be carried out on blood cultures?
Haemolysis
Coagulase testing
Gram staining
MALDI-TOF
What is the main coagulase positive bacteria?
Staphylococcus aureus
What is the minimum number of blood cultures required in endocarditis?
3, as the more blood that is taken, the higher the sensitivity
What are some bacteria that will NOT grow on agar?
Bartonella sp
Coxiella burnetti
Chlamydia sp
Legionella sp
Mycoplasma sp
Brucella sp
What is another name for Coxiella burnetti infection?
Q fever
Where is someone most likely to contract Coxiella burnetti?
During the birthing of livestock
Where is someone most likely to contract Brucella?
From goats
What is the mnemonic for slow growing bacteria?
HACEK
What are the HACEK bacteria?
H - Haemophilus sp
A - Aggregatibacter sp
C - Cardiobacterium sp
E - Eikenella sp
K - Kingella sp
What are some common bacteria that infect wound sites and implantable devices?
Staphylococcus epidermidis
Staphylococcus aureus
Corynebacterium sp
Proprionibacterium sp
How long after the removal of an ICED should blood cultures be taken?
48 - 72 hours
What can form on the heart valves as a result of infective endocarditis?
Vegetations
How does infective endocarditis increase the risk of stroke?
Vegetations are friable and so can form septic emboli which can pass into the carotid arteries
Describe the pathogenesis of endocarditis?
Damage to a heart valve due to hypertension or turbulent blood causes formation of platelet and fibrin rich clots on the endocardium
Bacteraemia can then allow for the deposition of bacteria in the clot, forming a vegetation
What are some common causes of damage to the heart valves, therefore increasing the risk of endocarditis?
Calcification
Congenital conditions
Rheumatic fever
What are some risk factors for infective endocarditis?
Heart valve damage
Prosthetic heart valves
IV drug users
Dental damage or work
Intravascular lines
What are the most common organisms in infective endocarditis?
Staphylococcus aureus
Streptococcus viridans group
Enterococcus sp
Staphylococcus epidermidis
What effect will staphylococcus aureus have on blood agar?
It will cause a gold ring to form
What are some common examples of Viridans group streptococci?
Strep. mitis
Strep. sanguinis
Strep. mutans
Strep. salivarius