CARDIO: Infective Endocarditis Flashcards
Diagnostic investigations for infective endocarditis?
Blood cultures (3 different sites over several hours) Transoesophageal Echocardiogram
What are some cardiac RF for developing Infective endocarditis?
Mitral valve prolapse Prosthetic (valves + patches NOT stents) bicuspid aortic valve disease rheumatic heart disease congenital heart disease
How are normal heart valves often involved in infective endocardiits?
previously normal heart valves can be infected due to a intravascular device e.g. central line?
What are the most common organisms involved in native-valve Infective Endocarditis?
Staph aurues is now the most common!
Strep viridans (50%) Staph aureus (20%)
What is the most common organism for Infective Endocarditis in IV drug users?
Staph aureus (50-60%) of cases
What is the organism most commonly involved in ‘early’ (up to 1 year) Infective Endocarditis, post prosthetic heat valve operation?
Peri-operative contamination- mainly staphylococci
especially coagulase - negative e.g. staph epidermis
What is the organism most commonly involved in ‘late’ Infective Endocarditis, post prosthetic heat valve operation?
Viridans streptococci
Staph aureus
coagulase negatvie staph e.g. staph epidermis
In Infective Endocarditis, what organisms might suggest concurrent disease of GU / GI tract?
Enterococcal infective carditis 10% of all cases
e.g. Enterococcus feacalis
Which groups of people at risk of contracting Infective Endocarditis due to Fungi (+ which types) ?
E.g. Candidas / Aspergillus sp.
Immunosuppression IV drug use cardiac surgery prolonged exposure to AB IV feeding
Why might blood cultures be negative in cases of infective endocarditis?
5% of those with IE is negative
often due to recent exposure to AB
or
Infection with slow growing / fastidious organisms e.g. streptococci, Coxiella Burnetii or Brucella
What is the main causes of mortality in Infective Endocarditis?
Heart failure
CNS emboli
uncontrolled infection
What features should make you immediately suspect Infective Endocarditis in a pt?
Unexplained fever
Bacteraemia
systemic illness
and / or new murmur
What initial investigations should be performed on a pt with suspected Infective Endocarditis you have just admitted to hospital?
Bloods:
FBC
ESR / CRP
U&E
LTF
urine dip analysis and MSU for microscopy / culutre.
BLOOD CULTURES - 3 SETS FROM 3 DIFFERENT SITES **
Imaging:
CXR
ECG
ECHOCARDIOGRAM - TRANS OESOPHAGEAL ECHOCARDIOGRAM **
How many blood cultures, over how long and where should you take in a pt with Infective Endocarditis?
at least 3 (ideally 6) from different sites over several hours.
Sampling during temperature peak does not make cultures more sensitive
In a pt who is STABLE and has Infective Endocarditis, is it reasonable to delay AB treatment to take blood cultures - TRUE / FALSE
TRUE
once AB have been given harder to identify a causative organism
What imaging modality should you use to visualise Infective Endocarditis?
Echocardiogram
Transthoracic echo - 65% of vegetations
Transoesophageal echo (TOE) - 95% of vegetations
Which type of echocardiography is better for detecting mitral valve and prosthetic valve vegetations?
Transoesophageal echocardiography (TOE)
Also better at detecting aortic root, septal abscesses and leaflet perforations
Diagnostic criteria for Infective Endocarditis: How many of major / minor criteria do you need to make a diagnosis?
2 major
or
1 major + 3 minor
or
5 minor
What are the major criteria for diagnosing Infective Endocarditis?
- +ve blood cultures
- typical org from 2 BC
- +ve BCs >12 hrs apart
- >3 +ve BCs >1hour - Endocardial involvement
- +ve echo findings (abscess / vegetations)
- New valvular regurgitation
- dehiscence of prosthesis
What are the minor criteria for diagnosing Infective Endocarditis?
- Predisposing valvular or cardiac abnormality
- IV drug user
- Pyrexia > 38°C
- Embolic phenomenon
- Vasculitic phenomenon
- Blood cultures suggestive (grown but not achieving major criteria)
- Suggestive echo findings (but not meeting major criteria)
In terms of the management of Infective Endocarditis, what is the general principal? (before organism specific)
AB therapy
tunnelled central venous line good for prolonged IV AB (discuss regimens with duty microbiologist)
What AB therapy is recommended for Infective Endocarditis caused by Viridans streptococci?
IV Benzylpenicillin
(+ low dose IV gentamicin 80 mg BD)
(Vancomycin if penicillin allergic)
What AB therapy is recommended for Infective Endocarditis caused by Enterococci e.g. Enterococcus faecalis?
IV amoxicillin
(+ low dose IV gentamicin 80 mg BD)
(Vancomycin if penicillin allergic)
What AB therapy is recommended for Infective Endocarditis caused by staphylocci, e.g. Staph aureus / Staph epidermis?
Flucloxacillin
Vancomycin if penicillin allergic
plus gentamicin / fusidic acid
