What is the most likely cause to account for the patient's symptoms?
A mycotic aneurysm of the infrarenal aorta.
What imaging features help you to consider a mycotic over a true saccular aneurysm of the aorta?
1. Lack of atheromatous calcification in the aneurysmal dilation, which would be expected in a long-standing atherosclerotic aneurysm; 2. Surrounding fat stranding inferring inflammatory process; 3. Later correlation with recent previous imaging demonstrating the fast size progression of the aneurysm.
Selected images of the previous CT 5 days prior
Exams performed in the community 5 days prior to the presentation to the ED. Non-contrast images demonstrating the same saccular aneurysm, but with significantly smaller dimensions.