Infective Endocarditis

Morning report today was about a patient presenting with a 2 month history of fevers, sweats, and a recent stroke. 

Otherwise healthy and we discussed a differential that could tie everything together - this included:

- Infective endocarditis
- "non-infective" endocarditis such as Libman-sacks endocarditis seen with SLE
- Malignancy leading to a hypercoaguable state, as well as other myeloproliferative disorders
- Vasculitis 

Story revealed that due to fevers, the patient had received multiple courses of antibiotics with transient defervescence, but the fever would return soon after stopping antibiotics. Additionally, a TTE done during his initial presentation was normal. 

When the patient presented to the team's attention, was noted to have a systolic ejection murmur raditating to the axilla, still febrile and ultimately the diagnosis was felt to be concerning enough for infective endocarditis that another TTE was ordered. This time demonstrating a mitral valve vegetation. (Had this been non-diagnostic, then a TEE would have been pursued).

Making a diagnosis: Duke's criteria

Major Criteria:

1. Positive blood cultures for endocarditis

• typical microorganisms
• persistent bacteremia
• single positive culture for Coxiella burnetti (Q fever)

2. Evidence of endocardial involvement

• Echo evidence
• NEW regurgitant murmur

Minor Criteria:


1. Fever 
2. Predisposing cardiac lesion or IVDU
3. Vascular phenomena: arterial emboli, septic emboli, mycotic aneurysms, ICH, conjunctival hemorrhages, Janeway Lesions
4. Immunologic phenomena: GN, Osler's nodes (painful...think "Ooooowwsler's nodes"), Roth spots, positive RF
5. Positive blood cultures but not typical bacteria

Principles of management of IE

- Culture culture culture
- Unless evidence of sepsis, septic emboli, florid CHF, there is often not an immediate urgency to give antibiotics and you should always be sure that all microbiologic investigations are done before starting antibiotics.
- Most "culture-negative" organism can now be grown pretty well in our labs
- Prior antibiotic exposure is the biggest reason for culture negative IE
- Empiric antibiotics depends on native vs prosthetic valve and should target known organisms for IE

Indications for CV Surgery (in general, case-by-case)

- Heart Failure
- Uncontrolled Infection
- Prevention of emboli


Click here for a review of infective endocarditis from the NEJM 2013.
See the Supplementary appendix for suggestions of empiric therapy.