Massive Pericardial Effusion and Type 3 Cardiorenal Syndrome as the Inaugural Presentation of Late-Onset Systemic Lupus Erythematosus in a Septuagenarian

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by inflammation and immune-mediated damage with mucocutaneous, musculoskeletal, cardiopulmonary, and renal involvement. It typically affects younger women; however, late-onset presentations can occur and often display distinct clinical features. We report the case of a septuagenarian woman who presented with massive pericardial effusion and type 3 cardiorenal syndrome. Further evaluation revealed class IV lupus nephritis, confirming a diagnosis of late-onset SLE according to the 2019 European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) criteria. Cardiac and serous membrane involvement is more common in late-onset SLE than in classical SLE.