Primary aortic infections and infected aneurysms

Abstract

Primary infections of the aorta and infected aortic aneurysms are rare and are life threatening. Most of them are due to bacterial infection occurring in an atheromatous plaque or a pre existing aneurysm during bacteremia. Rarely spread from a contiguous septic process may be the cause. The reported hospital mortality ranges from 16-44%. Gram positive bacteria are still the most common causative organisms. More recently, Gram negative bacilli are seen increasingly responsible. The mortality rate is higher for the Gram negative infection since they most often cause supra renal aneurysms and are more prone for rupture. Best results are achieved by appropriate antibiotics and aggressive surgical treatment. Excision of the infected aneurysm sac as well as surrounding tissue and in situ reconstruction of aorta is the preferred treatment. Pedicled omental cover also helps to reduce infection. Long term antibiotic is needed to prevent reinfection. Mortality is high for those who undergo emergency operation, with advanced age and for nonsalmonella infection.

Keywords: aorta; aortitis; mycotic aneurysm; pseudo aneurysm.

Fig. 1

CT Aortogram showing multiple saccular out pouching-suggestive of infective etiology.

Fig. 2

CT image of the same patient showing aortic aneurysm with evidence of periaortic Inflammation, abscess and absence of calcification. There is an abscess within the right Psoas muscle.

Fig. 3

Operative photo showing the infected sac and the posterior rupture of the same patient.

Fig. 4

In situ Aortic reconstruction after complete excision of the infected tissue with silver impregnated coated Dacron graft. The graft was also wrapped with pedicled omentum.