Case report of culture-negative endocarditis in lupus nephritis.

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 ischaemia. On examination, she had poor dentition and a short systolic murmur on auscultation. A blood workup 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.