Mycotic aneurysm of the descending thoracic aorta in a 2-kg neonate.

Umbilical artery catheterization is often performed in critically ill neonates. Infection and thromboembolic events are relatively frequent complications, but aneurysm formation is rare. We describe the case of a premature baby who developed a rapidly expanding aneurysm of the descending thoracic aorta, secondary to a highly placed infected umbilical catheter. The rapid progression under medical therapy prompted us to replace the thoracic aorta with an 8-mm polytetrafluoroethylene graft, using extracorporeal circulation and core cooling. The baby had an excellent recovery and was discharged home after a prolonged antibiotic course. He is being followed with repeated imaging studies for a small abdominal aneurysm. We describe a novel approach to this rare and complicated problem and provide a review of the literature on the subject.