Purulent pericarditis and cardiac tamponade caused by Nocardia asteroides in mixed connective tissue disease. Pericardial nocardiosis is extremely rare, but may affect especially immunocompromised hosts. We describe the first reported case of purulent pericarditis with cardiac tamponade as the initial presentation of systemic nocardiosis in a patient with mixed connective tissue disease. Our case emphasizes the importance of identifying infectious causes of pericarditis in patients with connective tissue diseases. Longterm survival was achieved with a combined medical and surgical approach. 