Mycotic pseudoaneurysm of the thoracic aorta with purulent pericarditis.

Mycotic pseudoaneurysms are vascular lesions composed of laminated clot and fibrous tissue and containing bacterial microorganisms. The case reported here it the third in the English literature to describe the association of purulent pericarditis with rupture of a mycotic aortic aneurysm. A 65-year-old male developed cardiac tamponade secondary to Staph. aureus pericarditis. Following a surgical procedure to drain the pericardial sac, the postoperative course was complicated by fatal hemorrhage from a ruptured thoracic pseudoaneurysm. Postmortem examination indicated that the aortic pseudoaneurysm originated at the site of an ulcerated atherosclerotic plaque. A Staph. aureus infection of the aortic lesion, with erosion into the pericardial space, was the apparent cause of purulent pericarditis.