Libman-Sacks Endocarditis as the First Presentation of Systemic Lupus Erythematosus in a Young Man: A Multisystemic Diagnostic Challenge

Systemic lupus erythematosus (SLE) is a complex, phenotypically varied disorder that possesses wide-ranging cardiac involvement. Libman-Sacks endocarditis (LSE) is one such cardiac manifestation, which results from the deposition of verrucous, sessile lesions favoring the left-sided heart valves. LSE is typically clinically silent without significant valvular dysfunction. Such patients with LSE, however, are those most susceptible to a more severe clinical phenotype resulting from SLE. Here, we report a unique case of a 22-year-old man initially presenting with unilateral leg swelling found to be secondary to a deep-vein thrombosis. He subsequently developed a constellation of acute symptoms, including embolic strokes, splenic infarction, proteinuric kidney injury, and significant mitral regurgitation, all of which mimicked bacterial endocarditis. His complex, multi-systemic disease course presented diagnostic challenges. We highlight the need in such complex cases for a specialist-led multidisciplinary approach, including cardiologists and rheumatologists, to guide serological and radiological investigations. Early use of echocardiography, in particular 3D transesophageal imaging, was paramount in clinching the diagnosis of LSE as an index presentation of SLE and in the transition from intravenous antibiotics to immunosuppression. Our case underscores the importance of the multidisciplinary team and the role of echocardiography in identifying such patients with LSE in SLE and thereby those most vulnerable to significant end-organ sequelae.