The infectious and inflammatory abdominal aortic aneurysm

Commonly, abdominal aortic aneurysm (AAA) has an atherosclerotic origin; however, rare cases are immune-related, such as those from IgG4, or due to infections. Among the infectious agents, we remember the tuberculosis bacillus, the Salmonella typhi, but also Streptococcus sp., Staphylococcus sp., Escherichia coli, Pseudomonas aeruginosa, and the Treponema pallidum. Clearly, in these cases it can be advanced the hypothesis that a pre-existing AAA can become colonized by infectious agents, independently present in the same patient and already responsible of an acute or chronic infectious disease. The ways of this contamination can be hematogenous, lymphatic or developing through a direct contiguity. In course of immune disorder, the clinical and radiological features can be nonspecific, but the diagnosis is facilitated by the concomitant presence of a rheumatologic disease, with a local and/or systemic involvement. The pathophysiology of these cases is not yet completely understood, but we can considered as potential pathogenetic factor a primary vasculitis of the arterial vessel of the aortic walls. However, it has to be considered that also in rheumatologic patients, mainly if aged and with proper risk factors, vascular atherosclerotic diseases can develop independently from any associated pathology. The interest of this topic, other than general, is prognostic and implicates an adequate and correct choice of treatment.