Provenance and peer review Not commissioned; externally peer reviewed.Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy. ORCID iDAyesha Javaid http://orcid.org/0000-0001-5762-0233

Background Cardiovascular involvement is frequent in systemic lupus erythematosus (SLE). Valvular abnormalities are increasingly being recognized with the advent of echocardiography. Case Summary We present a case of a 46-year-old lady who presented to the Emergency Department with upper limb ischemia. On examination, she had poor dentition and a short systolic murmur on auscultation. Blood work up revealed a diagnosis of SLE. Further investigations showed vegetations on the mitral valve. Initially, an infective endocarditis (IE) diagnosis was made; which was treated with antibiotics. High-dose steroids and immunosuppressants were initiated due to her clinical deterioration and biopsy-proven lupus nephritis. She improved clinically before being discharged home. Discussion It can be difficult to distinguish between IE and Libman - Sacks Endocarditis (LSE), especially in the setting of risk factors for both. Antibiotics and immunosuppressants might be started simultaneously in these cases. A multidisciplinary team is required to manage challenging cases of culture-negative endocarditis. Procalcitonin may have a role in differentiating bacterial endocarditis and LSE.