Libman-Sacks endocarditis in SLE characteristically involves which cardiac structures and has what distinctive pathological feature that helps distinguish it from infective endocarditis?

• A Affects only the mitral valve atrial surface; vegetations are large and friable with septic emboli
• B Affects only the aortic valve; vegetations cause perforation and massive aortic regurgitation
• C Affects both surfaces of the mitral valve (atrial and ventricular); vegetations are sterile, small, and non-destructive ✓
• D Affects the right-sided valves exclusively in intravenous drug users; vegetations grow rapidly

Explanation

Libman-Sacks endocarditis (non-infective thrombotic endocarditis of SLE) is characterised by small (1-4 mm), flat, irregular, warty vegetations that classically involve BOTH surfaces of the mitral valve — both the atrial surface (facing blood from LA) and the ventricular surface (which is unusual; infective endocarditis typically favours the atrial surface of AV valves and ventricular surface of semilunar valves due to haemodynamic jet patterns). The vegetations in Libman-Sacks are sterile, fibrin-platelet thrombi with anti-phospholipid antibody association, and are non-destructive to valve cusps (no perforation), distinguishing them from infective endocarditis vegetations which are large, destructive, and microorganism-laden. They may not cause significant valvular dysfunction.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.