Purulent Pericarditis With Cardiac Tamponade Triggered by Left-Sided Infective Endocarditis in Active Systemic Lupus Erythematosus: A Case Report

Systemic lupus erythematosus (SLE)-associated pericardial effusion is generally sterile, and purulent pericarditis is rare; however, delayed recognition can be fatal. In active SLE, immunologic abnormalities - such as hypocomplementemia and impaired neutrophil function - together with concurrent immunosuppressive therapy, may predispose patients to invasive infections. We report a rare clinical course in which left-sided infective endocarditis in a patient with active SLE progressed to purulent pericarditis and cardiac tamponade, underscoring the need for rapid diagnostic consideration and timely intervention. A 32-year-old woman presented with fever, dyspnea, and rapidly progressive shock. Imaging revealed massive circumferential pericardial effusion with cardiac compression. After obtaining blood cultures, empiric intravenous antimicrobial therapy was initiated, and fluoroscopy-guided pericardial drainage yielded a large volume of brownish, purulent-appearing effluent. Transthoracic echocardiography demonstrated vegetation and perforation of the anterior mitral leaflet with mitral regurgitation. Blood cultures grew methicillin-susceptible <i>Staphylococcus aureus</i>, and she was diagnosed with left-sided infective endocarditis complicated by purulent pericarditis. Because emergent surgical indications were absent early in the course and postoperative infectious risk was a concern in the setting of active purulent pericarditis, management prioritized infection control and hemodynamic stabilization. However, cardiac surgery became infeasible after a catastrophic intracerebral hemorrhage, and the patient died on hospital day 38. This case highlights the key clinical takeaway that, in patients with active SLE and pericardial effusion accompanied by fever or hemodynamic deterioration, clinicians should promptly evaluate for infectious pericarditis and concomitant infective endocarditis by obtaining blood cultures, performing echocardiography for valvular involvement, and, when indicated, undertaking timely pericardial drainage with microbiological evaluation.