Systemic Lupus erythematosus (SLE) is an autoimmune disorder characterized by the proliferation of autoantibodies and immune dysregulation resulting in damage to many body organs. Pediatric SLE usually presents with fever, joint pain, rashes, and lupus nephritis. It is uncommon to have large pericardial effusions in children with SLE and cardiac tamponade as the initial presentation of SLE is even rarer. An 11-year-old female presented to our Children Emergency Unit with fever and fast breathing for two weeks, bilateral leg swelling of four days, and cough of two days duration. She was acutely ill, tachypneic, and dyspneic with marked orthopnea, bilateral leg edema, and raised JVP. She was tachycardic with a diffuse apex beat. Chest X-ray showed a large globular heart. 2D-Echocardiography showed a large circumferential pericardial effusion with a dilated non-collapsing IVC and diastolic collapse of the right ventricle. She had a pericardiotomy done and 650mls of serous pericardial fluid was drained. The inner pericardium had a fibrinoid exudate with a "bread-and-butter" appearance. Pericardial fluid cytology showed no malignant cells while pericardial biopsy showed suppurative granulomatous inflammation. Antinuclear antibody (ANA) was strongly positive. The patient was managed with corticosteroids, colchicine, and hydroxychloroquine, and has remained stable on follow-up. While cardiac tamponade as an initial presenting complaint in SLE is rare, it is important that children presenting with large pericardial effusions and tamponade be evaluated for rheumatologic disorders. This can be crucial to revealing the correct diagnosis and instituting appropriate care. [ABSTRACT FROM AUTHOR]