Mycotic aneurysm of the abdominal aorta
The preoperative computed tomogram shows gas in the anterior wall of the aorta. Postoperatively where gas had previously been noted there was aneurysmal degeneration in the area of the abdominal aorta.
This mycotic aneurysm was presumably due to septic emboli of a cardiac source that became lodged in the wall of the aorta or in the vasa vasorum. Staphylococcus aureus was grown from cultures of the aneurysm wall. Revascularization of the lower extremities was performed with placement of an axillobifemoral bypass graft. Arterial wall ischemia and infection result in destruction of the media and aneurysm formation. These aneurysms may be multiple, being found predominantly in the aorta, intracranial arteries, superior mesenteric and femoral arteries. Other types of infected aneurysms include those secondary to microbial arteritis, atherosclerotic aneurysms secondarily infected, and traumatic infected false aneurysms.1
General principles of surgical care of infected aneurysms include aneurysm resection with débridement of surrounding infected tissue. Arterial reconstruction is performed through noninfected tissue planes, and antibiotics are continued postoperatively for a prolonged period.