CARDIO: Infective Endocarditis Flashcards Preview

Year 3 Medicine Block > CARDIO: Infective Endocarditis > Flashcards

Flashcards in CARDIO: Infective Endocarditis Deck (28)
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1
Q

Diagnostic investigations for infective endocarditis?

A
Blood cultures (3 different sites over several hours)
Transoesophageal Echocardiogram 
2
Q

What are some cardiac RF for developing Infective endocarditis?

A
Mitral valve prolapse
Prosthetic (valves + patches NOT stents)
bicuspid aortic valve disease
rheumatic heart disease
congenital heart disease
3
Q

How are normal heart valves often involved in infective endocardiits?

A

previously normal heart valves can be infected due to a intravascular device e.g. central line?

4
Q

What are the most common organisms involved in native-valve Infective Endocarditis?

A

Staph aurues is now the most common!

Strep viridans (50%)
Staph aureus (20%)
5
Q

What is the most common organism for Infective Endocarditis in IV drug users?

A

Staph aureus (50-60%) of cases

6
Q

What is the organism most commonly involved in ‘early’ (up to 1 year) Infective Endocarditis, post prosthetic heat valve operation?

A

Peri-operative contamination- mainly staphylococci

especially coagulase - negative e.g. staph epidermis

7
Q

What is the organism most commonly involved in ‘late’ Infective Endocarditis, post prosthetic heat valve operation?

A

Viridans streptococci

Staph aureus

coagulase negatvie staph e.g. staph epidermis

8
Q

In Infective Endocarditis, what organisms might suggest concurrent disease of GU / GI tract?

A

Enterococcal infective carditis 10% of all cases

e.g. Enterococcus feacalis

9
Q

Which groups of people at risk of contracting Infective Endocarditis due to Fungi (+ which types) ?

A

E.g. Candidas / Aspergillus sp.

Immunosuppression
IV drug use 
cardiac surgery 
prolonged exposure to AB
IV feeding
10
Q

Why might blood cultures be negative in cases of infective endocarditis?

A

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

11
Q

What is the main causes of mortality in Infective Endocarditis?

A

Heart failure
CNS emboli
uncontrolled infection

12
Q

What features should make you immediately suspect Infective Endocarditis in a pt?

A

Unexplained fever
Bacteraemia
systemic illness
and / or new murmur

13
Q

What initial investigations should be performed on a pt with suspected Infective Endocarditis you have just admitted to hospital?

A

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 **

14
Q

How many blood cultures, over how long and where should you take in a pt with Infective Endocarditis?

A

at least 3 (ideally 6) from different sites over several hours.

Sampling during temperature peak does not make cultures more sensitive

15
Q

In a pt who is STABLE and has Infective Endocarditis, is it reasonable to delay AB treatment to take blood cultures - TRUE / FALSE

A

TRUE

once AB have been given harder to identify a causative organism

16
Q

What imaging modality should you use to visualise Infective Endocarditis?

A

Echocardiogram

Transthoracic echo - 65% of vegetations

Transoesophageal echo (TOE) - 95% of vegetations

17
Q

Which type of echocardiography is better for detecting mitral valve and prosthetic valve vegetations?

A

Transoesophageal echocardiography (TOE)

Also better at detecting aortic root, septal abscesses and leaflet perforations

18
Q

Diagnostic criteria for Infective Endocarditis: How many of major / minor criteria do you need to make a diagnosis?

A

2 major

or

1 major + 3 minor

or

5 minor

19
Q

What are the major criteria for diagnosing Infective Endocarditis?

A
  1. +ve blood cultures
    - typical org from 2 BC
    - +ve BCs >12 hrs apart
    - >3 +ve BCs >1hour
  2. Endocardial involvement
  3. +ve echo findings (abscess / vegetations)
  4. New valvular regurgitation
  5. dehiscence of prosthesis
20
Q

What are the minor criteria for diagnosing Infective Endocarditis?

A
  1. Predisposing valvular or cardiac abnormality
  2. IV drug user
  3. Pyrexia > 38°C
  4. Embolic phenomenon
  5. Vasculitic phenomenon
  6. Blood cultures suggestive (grown but not achieving major criteria)
  7. Suggestive echo findings (but not meeting major criteria)
21
Q

In terms of the management of Infective Endocarditis, what is the general principal? (before organism specific)

A

AB therapy

tunnelled central venous line good for prolonged IV AB (discuss regimens with duty microbiologist)

22
Q

What AB therapy is recommended for Infective Endocarditis caused by Viridans streptococci?

A

IV Benzylpenicillin

(+ low dose IV gentamicin 80 mg BD)

(Vancomycin if penicillin allergic)

23
Q

What AB therapy is recommended for Infective Endocarditis caused by Enterococci e.g. Enterococcus faecalis?

A

IV amoxicillin

(+ low dose IV gentamicin 80 mg BD)

(Vancomycin if penicillin allergic)

24
Q

What AB therapy is recommended for Infective Endocarditis caused by staphylocci, e.g. Staph aureus / Staph epidermis?

A

Flucloxacillin

Vancomycin if penicillin allergic

plus gentamicin / fusidic acid

25
Q

How would you recommend response to AB therapy in a pt with Infective Endocarditis? imaging, bloods etc

A
  1. bedside reviews of clinical status
  2. Echo 1 x weekly
    (vegetation size, complications e.g. abscess / valve destruction)
  3. ECG 2 x weekly
    conduction disturbances- aortic root abscess / valve infection
  4. Blood tests 2 x weekly
    ESR / CRP/ FBC / U&Es

AB - 6 weeks depending on response

26
Q

Referral for surgery is indicated for pts with Infective Endocarditis who have …..

A
  • Cardiac failure (valve compromise)
  • Valve dehiscence
  • Uncontrolled infection despite AB
  • Fungal / Coxiella burnetii infection
  • Relapse after medical therapy
  • Threatened / actual systemic embolism
  • Para-valvular infection (aortic root abscess)
  • Valve obstruction

Common exam question: PR interval prolongation in a patient with Infective Endocarditis is an indication for surgery as it can be secondary to aortic root abscess

27
Q

Diagnostic investigations for infective endocarditis?

A
Blood cultures (3 different sites over several hours)
Echocardiogram (transoesophageal)
28
Q
A

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