Cardiac Infection Flashcards
What questions should you think about when you get back positive blood cultures?
What is the usual habitat of this organism? What disease is this organism associated with? What is the optimum antimicrobial management required?
What are the pre-disposing factors for infective endocarditis?
Heart valve abnormality, prosthetic heart valve, IV drug users, intravascular lines.
Describe the pathogenesis of infective endocarditis.
Heart valve damage -> turbulent bloodflow over roughened endothelium -> platelets/fibrin deposited -> bacteraemia -> organisms settle in thrombi becoming microbial vegetation.
What is the common side of the heart affected by infective endocarditis?
Left side of heart.
What are the common organisms causing infective endocarditis?
Staph aureus, viridans streptococci, enterococcus sp, staph epidermidis.
Give examples of atypical organisms that can cause infective endocarditis.
Bartonella, coxiella burnetti (Q-fever), chlamydia, legionella, mycoplasma, Brucella (all difficult to grow, can be detected in serology).
What are some gram negative organisms that cause infective endocarditis?
HACEK organisms (haemophilus spp, aggergatibacter spp, cardiobacterium, Eikenella sp, Kingella sp.). Others.
What are the 3 major criteria for the modified duke criteria?
- 2 separate positive blood cultures with microorganisms typical for infective endocarditis.
- Echocardiographic evidence of endocardial involvement.
- New valvular regurgitation.
What are the 3 minor criteria for the modified duke criteria?
- Predisposition.
- Temp greater than 38*C.
- Vascular phenomena.
- Immunological phenomena.
- Microbiological evidence.
What echo would you do first and then second?
Trans thoracic echo (TTE), then trans oesophageal echo (TOE).
If someone has a prosthetic heart valve, what is the likely infective organism?
Staph epidermidis.
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 (round white retina spot), Janeway lesions (flat painless coloured bit on hands and feet), Osler nodes (tender red spots on fingers and toes), microscopic haematuria (blood in urine).
What kind of haemolysis does viridans strep do?
Alpha (looks green).
What is the difference between early (within 60 days) and late presentations of prosthetic valve endocarditis?
Early: usually infected at time of valve insertion and usually due to staph epidermidis or aureus.
Late: wide range of possible organisms.