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Although the presenting features of Takayasu arteritis vary greatly, they can be categorized into two broad groups: those caused by vascular damage (ie, occlusion, stenosis, or dilation of blood vessels), and those caused by systemic inflammation (Table 31–1). The separation of these presenting features is not always neatly maintained; many patients have both vascular complications and constitutional symptoms, and others have a biphasic presentation, with constitutional symptoms dominating early and vascular features becoming more salient later.
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Among the vascular manifestations, bruit, claudication, hypertension, light-headedness (associated with vertebral or carotid artery disease), unequal blood pressures in the extremities, carotidynia, aortic regurgitation, and loss of a pulse are most common. Bruits develop most frequently over the carotid arteries, but also often develop in the supraclavicular or infraclavicular space (reflecting subclavian disease), along the flexor surface of the upper arm (from axillary artery disease), or in the abdomen (from renal or mesenteric artery vasculitis). Many patients have multiple bruits. Upper extremity claudication—commonly manifested in young women by fatigue and pain in the arm while exercising or blow-drying hair—develops more often than lower extremity claudication. A widened pulse pressure and diastolic murmur along the right sternal border may signal the aortic regurgitation that develops in 20% of patients. Other cardiac manifestations include angina (most commonly from stenotic lesions at or near the ostia of the coronary arteries), mitral regurgitation (secondary to left ventricular dilatation from aortic regurgitation), or congestive heart failure (early in the course caused by myocarditis or late in the course caused by chronic aortic with or without mitral regurgitation). Stroke affects a significant minority of patients. Glomerulonephritis is quite rare in this form of large vessel vasculitis; renal disease usually results from hypertension which in turns develops because of stenosis of the renal arteries.
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The visual symptoms that were first described in 1908 occur rarely today. When present, visual symptoms chiefly result from retinal ischemia produced by narrowing or occlusion of the carotid arteries. Some patients may have such limited blood flow through their carotids and vertebral arteries that merely turning and tilting their head causes light-headedness, dizziness, or visual loss.
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Almost half of patients experience constitutional or musculoskeletal symptoms. These constitutional and musculoskeletal features dominate the presentation in approximately one third of all cases of Takayasu arteritis. Asthenia, weight loss, fever, myalgia, and arthralgia occur commonly. Prominent back pain, especially in the thoracic region, develops in a few patients. This pain resembles that seen in older patients with thoracic dissection and probably results from stimulation of nociceptive nerve fibers along the inflamed aorta.
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Takayasu arteritis does not cause any specific blood test or urinary abnormalities but usually produces nonspecific findings of inflammation. Nearly 80% of patients have elevated erythrocyte sedimentation rates (ESR) or C-reactive protein (CRP) values, especially during phases of active disease. Unfortunately, no blood test accurately measures disease activity. For example, the ESR is normal in 30% of patients with active disease and is elevated in 40% of patients with inactive disease. Recent studies have suggested that pentraxin-3 may more accurately reflect disease activity than either ESR or CRP. Anemia develops in 50% of patients, with hematocrits typically in the high 20s or low 30s. Anemic patients commonly have slightly low mean corpuscular volume (eg, high 70s). Thrombocytosis, which develops in one-third of patients, is often mild but may exceed 800,000/mcL. Less than 10% of patients with Takayasu arteritis have an elevated serum creatinine. About one quarter will have mild proteinuria or hematuria. Renal abnormalities usually result from hypertension; glomerulonephritis from Takayasu arteritis very rarely occurs.
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Magnetic resonance imaging (MRI), computed tomography (CT), vascular ultrasonography, and conventional aortography are abnormal in virtually all patients with Takayasu arteritis. MRI appears most sensitive in that it can detect the inflammatory thickening of the aorta or its branches (Figure 31–1) that precedes changes in the caliber of the vessels’ lumen. Conventional angiography, although unhelpful in determining the thickness of the vessel wall, provides the most detailed images of the stenoses, occlusions, dilatation, and other vascular wall irregularities characteristic of Takayasu arteritis (Figure 31–2). Advances in CT and three-dimensional image reconstruction have allowed CT angiography to replace the more invasive conventional angiograms.
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The most frequently affected vessels are the aorta, subclavian arteries, and carotid arteries (Table 31–2). Involvement of the aorta above and below the diaphragm occurs most commonly. The distribution of vascular involvement varies in people from different countries: whereas disease of the ascending aorta and great vessels is most common in patients from Japan, involvement of the abdominal aorta and renal arteries is most common in patients from India and Korea. In the extra-aortic vessels, long segments of stenosis are more frequent than dilation or aneurysm. Takayasu arteritis is one of the few forms of vasculitis that can affect, albeit rarely, the pulmonary arteries. Positron emission tomography scanning offers the theoretical advantage of allowing quantification of the degree of vascular inflammation. Indeed, positron emission tomography scanning appears to be sensitive in detecting vascular inflammation in patients with Takayasu arteritis, but the cost and level of radiation exposure pose important limitations. No imaging technique has been proven to be reliable in measuring disease activity. The initial enthusiasm for the ability of MRI to measure disease activity has not been substantiated by long-term follow-up studies.
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Biopsies of the aorta or other actively affected arteries show a granulomatous vasculitis with giant cells.