Infective Endocarditis Flashcards
What is bacteraemia?
Presence of bacteria in the bloodstream. also known as septicaemia.
What is infective endocarditis?
Infection of the endothelium of the heart Valves.
Can be life threatening
Acute or sub-acute
Predisposing factors for endocarditis?
- Heart valve abnormality
- congenital heart defects
- age related calcification/sclerosis
- post rheumatic fever - Metal valve
- IV drug users
- Intramuscular lines
Summarise the pathogenesis of endocarditis
- Damaged valves
- turbulent blood flow over rough endothelium
- fibrin and platelets deposits over endothelium
- transient bacteraemia (e.g. from dental treatment)
- bacteria settle on the platelets/thrombi
- microbial vegetation
How can the microbial vegetations lead to haemorrhages?
Infected vegetations may break off and occlude or completely block a vessel–> abscess or haemorrhage.
Usually left side affected
4 Most common bacteria causing endocarditis?
- Staph aureus
- Viridans streptococci
- Enterococcus sp
- Staph Epidermis
Some unusual organisms causing endocarditis?
Atypical- coxiella, mycoplasma, legionella etc
gram - = Haemophilus, cardiobacterium, kingella
Fungi
How do Staph aureus show up in Gram film?
Purple. Cocci in clusters
Where is Staph Epidermis normally found?
Skin contaminant. Can cause infection in prosthetic valves/ intramuscular lines.
Presenting symptoms of acute endocarditis?
- Overwhelming Sepsis
- Cardiac failure.
Subacute
- Fever
- Breathlessness
- Malaise
- Weight loss
- Tiredness
What are some signs of sub acute endocarditis
- Splinter haemorrhages
- Oslers nodes, Janeway lesions, Roth spots
- fever
- Murmurs
- Splenomegaly
- Clubbing
What test must be done to confirm endocarditis?
Blood culture of 3 sets to confirm causative organism.
If Negative- consider serology of atypical organisms
What are the causative organisms behind early presentations of endocarditis in prosthetic valve replacements?
Early- within 60 days of replacement
- Staph Epidermis
- Staph aureus.
Late- can be many years after. due to co-incidental bacteraemia. Wide range of causative organisms.
What is the treatment for native valve endocarditis?
Amoxicillin + Gentamicin IV
What is the treatment for prosthetic valve endocarditis?
Vancomycin + Gentamicin IV.
Rifampicin orally. Added 3-5 days after initial treatment
May need valve replacement.
