Modified Duke criteria for infective endocarditis (IE) require how many criteria for a 'definite' clinical diagnosis, and which finding constitutes a SINGLE major criterion?

• A 2 minor criteria; new murmur of regurgitation
• B 2 major criteria OR 1 major + 3 minor criteria OR 5 minor criteria; persistently positive blood cultures with typical IE organism ✓
• C 1 major + 2 minor criteria; echocardiographic evidence of vegetation alone
• D 3 major criteria; positive serology for Coxiella burnetii

Explanation

Modified Duke criteria (Li 2000) classify IE as Definite if: 2 major criteria, OR 1 major + 3 minor, OR 5 minor criteria are met. Major criteria include: (1) positive blood cultures with typical IE organisms (S. viridans, S. bovis, HACEK, S. aureus, or Enterococcus) in ≥2 separate cultures drawn >12 hours apart, or persistently positive blood cultures; (2) echocardiographic evidence (vegetation, abscess, prosthetic valve dehiscence) or new valvular regurgitation. A single major criterion is persistently positive blood cultures with a typical organism. Minor criteria include fever, predisposing cardiac/IV drug use, vascular/immunological phenomena, and microbiological evidence not meeting major criteria.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.