Aortitis is a broad spectrum of inflammatory conditions of the aortic wall that include infectious and non-infectious aetiologies. Infectious aetiologies (Salmonella, Staphylococcus, Streptococcus, Mycobacterial) most typically result in focal saccular aneurysmal dilatations although certain infections including tertiary syphilis can result in diffuse aneurysmal dilatation, most typically associated with pencil thin calcification in the ascending aorta.
Non-infectious aortitis is more common and includes large vessel vasculitides such as giant cell arteritis and Takayasu's arteritis although rarely seronegative spondyloarthropathies (aortic root/valve) and Behcet's disease can result in an aortitis. Involvement by SLE or rheumatoid is described, but is far less common. Aortitis is also associated with the group of conditions termed as chronic periaortitis that includes idiopathic retroperitoneal fibrosis, inflammatory abdominal aortic aneurysm, perianeurysmal aortitis and idiopathic isolated abdominal periaortitis. The latter can resemble Takayasu's arteritis in the abdominal aorta.
Many patients with aortitis present with pain, fever, fatigue or weight loss. Signs of mesenteric ischaemia or renal artery stenosis may also be present with vascular impairment dependent on the select abdominal aorta branch vessels involved. CT accurately depicts the enhancing mantle of soft tissue and any associated vascular narrowing. MRI can be helpful in demonstrating low T1/high T2 but also avid gadolinium enhancement. These abnormalities are also metabolically active with PET imaging and along with erythrocyte sedimentation rate can be used for monitoring following steroid or immunosuppressive therapy.