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Libman-Sacks Endocarditis — SCE Rheumatology MCQ

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ModerateSLE & Antiphospholipid SyndromeLibman-Sacks EndocarditisSCE Rheumatology

A 40-year-old woman with systemic lupus erythematosus and antiphospholipid syndrome develops progressive exertional dyspnoea. Echocardiography shows moderate mitral regurgitation, leaflet thickening and several small sessile vegetations on the mitral valve. Three sets of blood cultures obtained before antimicrobial treatment are negative, and she is afebrile with no clinical or biochemical evidence of infection. What is the most likely diagnosis?

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Correct answer: A — Libman–Sacks endocarditis

The diagnosis is **Libman–Sacks endocarditis**, a sterile inflammatory and thrombotic valvulopathy associated with SLE and antiphospholipid antibodies. The mitral valve is commonly affected, with leaflet thickening, small vegetations and consequent regurgitation. The absence of clinical inflammation and repeatedly negative pre-antibiotic blood cultures makes infective endocarditis substantially less likely, although negative cultures alone would not exclude infection. Mitral valve prolapse produces systolic leaflet displacement rather than vegetations. Rheumatic disease characteristically causes commissural fusion and chordal thickening, often resulting in stenosis. A papillary fibroelastoma is usually a discrete, often pedunculated valvular tumour rather than several sessile vegetations in this autoimmune context.

Reference: Alhuarrat MA et al. Contemporary demographics, diagnostics and outcomes in non-bacterial thrombotic endocarditis. Heart. 2022;108:1637–1643. https://pubmed.ncbi.nlm.nih.gov/17602939/