Endocarditis Flashcards
What is endocarditis?
- Infection of the endocardium
- formation of a vegetation
- Results in damage to cusp of valves
What are the valves and where are they?
- Mitral (from LA to LV)
- Aortic (LV to aorta)
- Tricuspid (RA to RV)
- Pulmonary (RV to pulmonary artery)
What is a vegetation made of?
- Platelets
- WBC
- Fibrin mesh
- RBC debris
- Organsims embedded in fibrin mesh
What is a vegetation made of?
- Platelets
- WBC
- Fibrin mesh
- RBC debris
- Organsims embedded in fibrin mesh
What is a vegetation made of?
- Platelets
- WBC
- Fibrin mesh
- RBC debris
- Organsims embedded in fibrin mesh
What is quorum sensing?
How organisms communicate with each other. They produce chemical messages which tell organisms to divide or become biochemically inert
Why does quorum sensing make infection hard to treat?
They can signal to become inert which means that antimicrobials will be less effective against them
What are the gram positive bacteria that cause endocarditis?
•Stapphylocci - coagulase negative staphylococci - Staph aureus (MSSA and MRSA) •Streptococci - strep. viridans - enterococci
What are the gram negative bacteria that cause endocarditis?
- HACEK organisms
- Pseudomonas aeruginosa
- Enterobacteriales (e.g. E coli)
What are the risk factors for native endocarditis?
•Underlying valve abnormalities: 55-75%
- aortic stenosis
- mitral valve prolapse
Which valve is most commonly affected in IVDU with endocarditis?
Tricuspid valve
What are the clinical features of an acute endocarditis?
- toxic presentation
- Progressive valve destruction and metastatic infection developing in days to weeks
- Most commonly s. aureus
What are the clinical features of chronic endocarditis?
- Mild toxicity
- Presentation over weeks to months
- Rarely leads to metastatic infection
- Most commonly strep viridians or enterococcus
What are the 3 main groups of clinical features of endocarditis?
- Early manifestations of infection
- Embolic events
- Late effects of infection
Explain the early manifestations of endocarditis
- Incubation approx 2 weeks but longer in PVE
- A fever and murmur (especially if new) is infective endocarditis until proven otherwise
- Fever is the most common sign and murmurs is present in 80-85%
- Malaise
Which type of endocarditis is a murmur often absent in?
Tricuspid endocarditis
Explain embolic events of endocarditis
•Can takes days-weeks to occur •Seen earlier in acute endocarditis •Small emboli - petechia - splinter haemorrhages - haematuria •Large emboli - CVA (stroke) - Renal infarction •Right sided endocarditis - septic pulmonary emboli
Explain the long term effects of endocarditis
•Immunological reaction: - splenomegaly - nephritis - vasculitic lesions of the skin and eye - clubbing •Tissue damage: - valve destruction - valve abscess
•Osler’s nodes
What are the signs of endocarditis in the hands?
- Clubbing
- Splinter haemorrhage
- Osler’s nodes
When should you consider IE as a diagnosis?
- In all patients with a S.aureus bacteraemia
- IVDU with any positive blood culture
- All patients with prosthetic valves and positive blood cultures
Explain the diagnosis of endocarditis
•3 sets of blood cultures (10ml bottles)
- Take samples before antibiotics using aseptic technique
•Echocardiograph: trans thoracic or trans oesophageal (invasive but higher sensitivity)
•Duke criteria (2 major/1 major + 3 minor/5 minor criteria)
Explain Duke criteria
•Major
- Typical organism in 2 separate blood cultures
- Positive echocardiogram or new valve regurgitation
•Minor
- Predisposition (heart condition or IVDU)
- Fever >38 degrees
- Vascular phenomena (e.g. septic emboli)
- immunological phenomena (e.g. osler nodes)
- Positive blood cultures (not meeting the major criteria)
What is the management of endocarditis?
- Antimicrobial therapy
* Surgical intervention
What are the indications for surgery for endocarditis?
- Heart failure
- Uncontrollable infection - abscess/ persisting fever + positive bloods for>7 days/ infection caused by multi drug resistant organisms
- Prevention of embolism - large vegetations and embolic episode
What is the duration of therapy for native valve endocarditis?
4 weeks
What is the duration of antimicrobial therapy for prosthetic valve endocarditis?
6 weeks
What is the antimicrobial therapy for streptococcus species?
- Benzylpenicillin
* Gentamicin
What is the antimicrobial theory for enterococcus species?
- Amoxicillin or Vancomycin
* Gentamicin
What is the antimicrobial therapy for S aureus (MSSA)?
- Flucloxacillin
* Gentamicin
What is the antimicrobial therapy for staph aureus (MRSA)?
- Vancomycin
* Gentamicin
What is the antimicrobial therapy for CoNS?
- Vancomycin
- Gentamicin
- Rifampicin
