Infective Endocarditis

Today we had a very high yield morning report on infective endocarditis.

Here is a recap of some important points from the discussion:

1) The Modified Duke's criteria is used to make the diagnosis.
Diagnosis is made by any of the following:
- pathology confirmation
- presence of 2 major criteria
- presence of 1 major and 3 minor criteria
- presence of 5 minor criteria

Possible endocarditis: 1 major and 1 minor OR 3 minor criteria are met.

Major Criteria:
A) Micro criteria (any of the following)
a) Culture of a typical endocarditis organism (in 2/2 cultures)
- Staph Aureus
- Viridans group Strep
- Strep gallolyticus (formerly Bovis) and nutritionally-variant strep
- HACEK organism
- Community-acquired enterococci (no primary focus)

b) Single positive culture of Coxiella Burnetti (Q fever) on culture or serology IgG positive >1:800

c) Persistently positive cultures with another organism: 3/3 positive or 3/4 positive.

B) Evidence of cardiac disease: do TTE first, then TEE if prosthetic valve OR at least possible I.E. by clinical criteria. Any of:
- vegetation
- abscess
- new partial dehiscence of prosthetic valve
- new regurgitant murmur

Minor Criteria: 
- Vascular phenomena: splinter hemorrhages, conjunctival hemorrhages, Janeway lesions,
- Embolic phenomena: Glomerulonephritis, RF positivity, Osler's nodes, Roth spots
- fever of at least 38 degrees
- predisposing condition: IVDU, congenital cardiac disease or prosthetic valve
- positive cultures not meeting descriptions above.

2) When is prophylaxis for endocarditis needed? In a high-risk patient AND a high-risk procedure
High risk patients:
- past IE
- prosthetic valve
- uncorrected cyanotic shunts, or in first 6 months post correction
- heart transplant valvulopathy

High risk procedure:
- dental with gingival manipulation
- transbronchial biopsy
- involving infected GI, GU, skin, muscle

3) When to consult cardiac surgery in endocarditis:
- refractory CHF or shock
- uncontrolled infection: abscess/fistula, ongoing fevers, ongoing culture positivity, or fungal or resistant organism
- very large vegetation (>1cm)
- reucrrent embolic phenomena


Check out this very recent small study published in NEJM which sheds some light on those "debatable" indications for cardiac surgery (ie. size of vegetation and embolic phenomena). In this study, patients randomised to early surgery had significantly fewer embolic events (most of these were strokes) than those who had conventional therapy. Of note, 77% of patients on the conventional therapy group went on to have surgery (just later) and there was no difference in 6 month mortality in the two groups.

Here is a link to the classic NEJM review on endocarditis