Rapidly progressive mitral valve disease from non-bacterial thrombotic endocarditis to mitral stenosis in systemic lupus erythematosus: a case report.

Background: Libman-Sacks endocarditis), a non-bacterial thrombotic endocarditis (NBTE) linked to systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS), typically causes valve regurgitation and embolism but can rarely mimic rheumatic mitral stenosis (MS). Case summary: This case involves a 59-year-old woman with a history of APS and SLE who presented with worsening dyspnoea and congestive heart failure. Initially, severe mitral regurgitation (MR) due to NBTE resolved with vitamin K antagonist therapy, yet she subsequently developed significant MS with commissural fusion, a rheumatic-like feature. Despite stable SLE activity, echocardiography revealed severe MS with high pulmonary pressures, warranting surgical valve replacement. Intraoperative findings confirmed rheumatic-like degeneration, but the patient experienced a fatal cerebral infarction post-surgery, likely due to APS. Discussion: This case highlights the progression of NBTE-related MR to rheumatic-like MS in an SLE patient with APS, an unusual clinical course. It underscores the importance of echocardiographic monitoring in similar cases, as chronic inflammatory changes in APS might mimic rheumatic pathology, necessitating vigilant management and timely intervention.