Patient with fever, new murmur, and positive blood cultures for Streptococcus viridans x2. How do I apply the Duke Criteria to confirm or rule out infective endocarditis?
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Modified Duke Criteria for Infective Endocarditis: MAJOR CRITERIA: 1. Positive blood cultures: Typical organisms (S. viridans, S. bovis, HACEK, S. aureus, Enterococcus) in 2 separate cultures; or persistently positive cultures >12 hours apart 2. Echocardiographic evidence: Oscillating intracardiac mass (vegetation), perivalvular abscess, or new partial dehiscence of prosthetic valve OR new valvular regurgitation MINOR CRITERIA: 1. Predisposing heart condition or IV drug use 2. Fever ≥38°C 3. Vascular phenomena: arterial emboli, septic pulmonary infarcts, mycotic aneurysm, Janeway lesions, conjunctival hemorrhages 4. Immunological phenomena: glomerulonephritis, Osler nodes, Roth spots, positive rheumatoid factor 5. Positive blood cultures (not meeting major criteria) or serological evidence of active infection DIAGNOSTIC CATEGORIES: - DEFINITE: 2 major, OR 1 major + 3 minor, OR 5 minor criteria - POSSIBLE: 1 major + 1 minor, OR 3 minor criteria - REJECTED: Alternative diagnosis, resolution with ≤4 days of antibiotics, or no IE found at surgery For your patient: - S. viridans x2 positive blood cultures = 1 MAJOR criteria - Fever + new murmur = 2 MINOR criteria - Perform TEE urgently to look for vegetation (TEE superior to TTE for IE) - If TEE shows vegetation = 2 Major criteria = DEFINITE IE - Start empirical IV benzylpenicillin + gentamicin while awaiting full workup
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