A 30-year-old IV drug user develops high fever, new aortic regurgitation murmur, and multiple peripheral embolic events. Blood cultures grow Staphylococcus aureus. Which of the following valvular lesions best describes infective endocarditis?
- A Small, sterile, warty vegetations along the line of valve closure
- B Flat, rigid, calcified plaques on the valve leaflets without inflammatory infiltrate
- C Large, irregular, destructive vegetations with neutrophilic infiltrate and abscess formation ✓
- D Myxomatous degeneration with redundant leaflets and chordae tendineae elongation
Correct answer: C. Large, irregular, destructive vegetations with neutrophilic infiltrate and abscess formation
Explanation
Infective endocarditis (IE) is characterized by large, irregular, friable vegetations composed of fibrin, platelets, inflammatory cells, and masses of organisms (bacteria/fungi). Acute IE (commonly S. aureus) is destructive — causing valve perforation, ring abscesses, and septic emboli to brain, kidneys, and spleen. Libman-Sacks endocarditis (SLE) produces small, sterile, warty vegetations on both sides of valve leaflets. Nonbacterial thrombotic (marantic) endocarditis produces small, sterile vegetations. Mitral valve prolapse shows myxomatous degeneration.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.