According to the modified Duke criteria, which of the following is classified as a major criterion for the diagnosis of infective endocarditis?

Explanation

## Modified Duke Criteria for Infective Endocarditis Diagnosis **Key Point:** The modified Duke criteria (1992, revised 2000) use major and minor criteria to establish the diagnosis of infective endocarditis. A diagnosis requires 2 major criteria, 1 major + 3 minor criteria, or 5 minor criteria. ### Major Criteria (2 required for diagnosis) | Major Criterion | Definition | |---|---| | **Blood cultures** | Positive for typical IE organisms (S. viridans, S. aureus, S. bovis, HACEK group, E. faecalis) OR persistent bacteremia | | **Echocardiography** | Oscillating mass on valve, paravalvular abscess, new regurgitation, or prosthetic valve dehiscence | ### Minor Criteria (≥3 required if <2 major) | Minor Criterion | Definition | |---|---| | **Predisposition** | Underlying heart disease, IV drug use | | **Fever** | Temperature >38°C | | **Vascular phenomena** | Septic emboli, mycotic aneurysm, Janeway lesions, splinter hemorrhages | | **Immunologic phenomena** | Osler nodes, Roth spots, rheumatoid factor, glomerulonephritis | | **Microbiological evidence** | Positive blood culture not meeting major criteria | **High-Yield:** Blood cultures positive for typical organisms are a MAJOR criterion because they directly identify the causative pathogen. Osler nodes, splinter hemorrhages, and other peripheral stigmata are MINOR criteria (immunologic/vascular phenomena), not major. **Warning:** A common exam trap is confusing major and minor criteria. Remember: **Blood cultures = MAJOR; Peripheral signs (Osler, splinter hemorrhages, Janeway) = MINOR**. ### Clinical Significance **Clinical Pearl:** The sensitivity of the modified Duke criteria is ~80–90% for native valve endocarditis and ~60–70% for prosthetic valve endocarditis. Early echocardiography (TEE preferred over TTE) is essential because it is the second major criterion and can establish diagnosis when blood cultures are negative or delayed. **Mnemonic:** **MAJOR = Microbes (blood culture) + Morphology (echo); MINOR = Manifestations (fever, peripheral signs)**