GI_011

Takayasu’s generally affects the large and medium vessels such as the aorta and its major branches. It has a strong female predominance (9:1) and a young age of onset. On CT there is wall thickening and enhancement early on, which progresses to stenosis/occlusion. There can be aneurysmal dilatation, and in the late stages the distal aorta can appear narrowed.

Polyarteritis Nodosa is a medium vessel vasculitis, with a characteristic finding of multiple aneurysm formation. These form after segmental weakening of the arterial wall due to inflammation. The symptoms are usually due to ischaemia and infarction of the affected organ. The renal arteries are most commonly involved, classically with multiple microaneurysms identified the kidney on angiography.

Fibromuscular dysplasia is a non-inflammatory vascular disease which commonly affects the renal arteries. It causes intermittent arterial stenosis and aneurysmal dilatation which gives a ‘string of beads’ appearance. It responds very well to angioplasty. Microscopic polyangitis is a small vessel vasculitis, and on angiography the tiny microaneurysms are not typically seen. Bechet’s is a vasculitis affecting multiple organ systems, but classically with a triad of oral and genital ulceration and uveitis. When it affects the GI tract, it causes large ulcerations, particularly in the terminal ileum.