musculoskeletal and connective tissue disorders
Takayasu Arteritis
Pathophysiology of Takayasu Arteritis
Takayasu arteritis affects primarily large elastic arteries. The most commonly affected are Innominate and subclavian arteries Aorta (mainly the ascending aorta and the arch) Common carotid arteries Renal arteries Most patients have stenoses or occlusions. Aneurysms occur in about one third of patients. Usually, the wall of the aorta or its branches thickens irregularly, with intimal wrinkling. When the aortic arch is affected, orifices of the major arteries emerging from the aorta may be markedly narrowed or even obliterated by intimal thickening. In one half of patients, pulmonary arteries are also affected. Sometimes the medium-sized branches of the pulmonary arteries are involved. Histologically, early changes consist of adventitial mononuclear infiltrate with perivascular cuffing of the vasa vasorum. Later, intense mononuclear inflammation of the media may occur, sometimes accompanied by granulomatous changes, giant cells, and patchy necrosis of the media. Morphologic changes may be indistinguishable from those of Giant Cell Arteritis . Panarteritic inflammatory infiltrates cause marked thickening of the affected artery and subsequent luminal narrowing and occlusion. 