Infected Aneurysm Caused by Salmonella Spp. At the Junction of the External Iliac and Common Femoral Artery

Aneurysms at the junction of the external iliac and common femoral artery are uncommon and their natural history is not well characterized, although they are the second most common type of true peripheral aneurysm. Aneurysms can become infected by direct inoculation of bacteria into the arterial wall at the time of vascular injury, bacteremic seeding of a pre-existing intimal lesion or atherosclerotic plaque, spread from a contiguous infectious focus or septic embolism (“mycotic aneurysm”), which can lead to vessel rupture. Microorganisms with greater affinity for the arterial wall most commonly include Staphylococcus spp. (28–71%) and Salmonella spp. (15–24%, resulting from bacteremia or local atherosclerotic plaque). This report describes the case of a 67-year-old male referred to a tertiary hospital in Paraná due to left inguinal pain and fever for 5 days. Laboratory tests showed an infectious pattern with leukocytosis and elevated C-reactive protein. Imaging identified a saccular aneurysm of the left common femoral artery measuring 5.7 × 5.6 cm. CT angiography showed fat stranding in adjacent myoadipose planes, suggesting a possible infected aneurysm. The patient underwent aneurysm ligation and extra-anatomic bypass. Intraoperatively, a large amount of pus and necrotic tissue was observed. Microbiological analysis was positive for Salmonella spp. Antimicrobial therapy with ceftriaxone was chosen based on susceptibility testing and administered for 10 days after surgical source control, with good outcome. This case therefore describes a rare condition that is difficult to suspect clinically and diagnose, with a high potential for complications, including vessel rupture and sepsis. Although less frequent than infection by Staphylococcus spp., Salmonella spp. infection is an important entity, underscoring the need for microbiological investigation in highly suspicious cases. This case emphasizes how integration among imaging, microbiology and surgical management is essential for accurate diagnosis and treatment, leading to good clinical outcomes and case resolution.