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Takayasu arteritis, named for the Japanese ophthalmologist who first described the ocular manifestations in 1908, is a large-vessel vasculitis of unknown cause that chiefly affects women during their reproductive years. The disease often presents two challenges. First, the diagnosis can be delayed for months or even years due to the rarity of the disease, the young age of the (typical) patient, and the protean presenting manifestations. Second, treatment is a challenge. Although Takayasu arteritis is a chronic disease, it usually pursues a waxing and waning course that requires careful monitoring to determine when the disease is active and medical therapy is needed. Treatment with glucocorticoids usually succeeds in halting progression of the vasculitis. Indeed, because of the advances in medical therapy and surgical treatment of vascular complications, such as aortic regurgitation, survival of patients with Takayasu arteritis has increased dramatically.
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- Causes vasculitis of the aorta and its major branches.
- Preferentially affects young women.
- Often presents with absent pulse, bruit, claudication, hypertension, or fever of unknown origin.
- Erythrocyte sedimentation rate is usually elevated.
- Most patients respond to prednisone.
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Although Takayasu arteritis has been most extensively reported in Japan, Korea, China, Southeast Asia, and Mexico, cases have been described worldwide. In North America, the annual incidence is about 1–3 cases per million people. Takayasu arteritis affects women eight times more frequently than men. The average age of diagnosis is in the mid-20s but the disease may begin as early as age 7 or as late as age 70. Symptoms develop before age 20 in nearly one third of patients and after age 40 in about 10%. The age of onset tends to be later in European countries.
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The cause of Takayasu arteritis remains elusive. The geographic clustering of cases suggests important genetic or environmental factors, but few have been identified. HLA associations have been found in Japanese patients (who preferentially express Bw52, DR2, Dw12, and DQw1), but not in other populations. The predominance of Takayasu arteritis in women of childbearing age suggests that female hormones may play a permissive role, as in systemic lupus erythematosus. An animal model of Takayasu arteritis has been produced with a herpes virus. In that model, the media of the aorta provides an immunoprivileged site for persistent herpes virus infection, which results in chronic inflammation (arteritis).
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However initiated, Takayasu arteritis appears to be propagated by a T-cell–driven immune response that results in a granulomatous inflammation affecting all layers of the vessel. Indeed, the histopathology of Takayasu arteritis cannot be distinguished from that of temporal arteritis (also called giant cell arteritis; see Chapter 30). The inflammatory injury mediated by activated T cells, macrophages, and cytokines often results in proliferation of the intima and of smooth muscle cells in the media, leading to occlusion and stenosis of the artery. Transmural inflammation can also cause aneurysmal dilation of the vessel. Overproduction of inflammatory cytokines, such as interleukin-6, results in fever and other constitutional symptoms.
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