Massive Hemorrhagic Pericardial Effusion With Cardiac Tamponade as Initial Manifestation of Mixed Connective Tissue Disease.

Mixed connective tissue disease (MCTD) is a distinct entity of connective tissue disorders characterized by overlapping clinical features of various autoimmune diseases along with the presence of antibodies to ribonucleoprotein (anti-RNP). The prevalence of cardiac involvement in MCTD varies from 13% to 65% and accounts for approximately 20% of MCTD related mortality. In this case, we describe an elderly female patient with multiple complaints without a clear etiology on presentation. Echocardiogram revealed severe rapidly accumulating pericardial effusion causing tamponade necessitating pericardial window. Laboratory investigations showed positive ribonucleoprotein antibodies. Biopsy of pericardial tissue revealed fibrinous pericarditis. While pericarditis is commonly associated with MCTD, pericardial tamponade on the other hand is rarely described. This case highlights a very rare complication of the disease. Early recognition, prompt treatment, and regular follow-up with serial echo are essential for treatment.