In libman-Sacks endocarditis associated with antiphospholipid syndrome, which of the following best describes the pathology and its clinical relevance compared to infective endocarditis?

• A Libman-Sacks endocarditis consists of large bulky friable vegetations exclusively on the ventricular surface of the mitral valve; caused by viridans streptococci in a previously normal valve
• B Libman-Sacks vegetations are calcified nodules on the ring of the aortic valve caused by dystrophic calcification in rheumatic fever
• C Libman-Sacks endocarditis exclusively involves the tricuspid valve and is a complication of venous thrombosis in antiphospholipid syndrome
• D Libman-Sacks endocarditis consists of small sterile vegetations on BOTH surfaces (atrial and ventricular) of all four valves; caused by anti-cardiolipin/anti-beta2-GP1 antibodies causing endothelial injury and fibrin-platelet deposition; a source of thromboembolism and stroke, but not bacterial seeding ✓

Explanation

Libman-Sacks endocarditis is a non-infective (marantic) endocarditis associated with SLE and antiphospholipid syndrome. Antiphospholipid antibodies (anti-cardiolipin, anti-beta2-glycoprotein I) cause endothelial injury and promote sterile fibrin-platelet thrombus formation, resulting in small, flat, irregular sterile vegetations. A cardinal feature is involvement of BOTH surfaces (atrial and ventricular aspects) of any valve leaflet, most commonly the mitral valve, distinguishing it from rheumatic fever (atrial surface, tips) and infective endocarditis (atrial surface, large). These vegetations are sources of thromboemboli causing stroke and renal infarcts in APS; Doppler echocardiography detects associated valvular regurgitation.

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

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Written and medically reviewed by the StethoPrep medical team.