Takayasu arteritis (TA) is a chronic progressive, nonspecific inflammatory disease of the aorta and its major branches. Lesions located in the aortic arch and its branches are most common, followed by the descending aorta, abdominal aorta, and renal arteries. Secondary branches of the aorta, such as the pulmonary and coronary arteries, may also be involved. Involved vessels may be total arteritis. In the early stages, the vessel wall is infiltrated by lymphocytes, plasma cells, and occasionally polymorphonuclear neutrophils and multinucleated giant cells. As a result of intimal thickening, the lumen is narrowed or occluded. In a few patients, inflammation destroys the middle layer of the arterial wall and necrosis of elastic and smooth muscle fibers, resulting in dilated arteries, pseudoaneurysms, or intercalated aneurysms. The disease occurs mostly in young women, accounting for about 90% of cases before the age of 30, and less frequently after the age of 40, with a prevalence of 2.6 per million in foreign countries. The cause of the disease is still unclear, but it is generally believed that it may be caused by immune damage caused by infection. Clinical manifestations] 1. Systemic symptoms A few weeks before the appearance of local symptoms or signs, a few patients may have general malaise, fatigue, fever, loss of appetite, nausea, sweating, weight loss, myalgia, arthritis and erythema nodosum, etc., which can be acute or insidious. When local symptoms or signs appear, systemic symptoms may gradually decrease or disappear, and some patients have no such symptoms. 2.Local symptoms and signs According to the affected vessels, there are signs and symptoms of ischemia in different organs, such as headache, dizziness, syncope, stroke, loss of vision, intermittent activity fatigue of the limbs, weakening or disappearance of brachial or femoral artery pulsation, vascular murmur in the neck, supraclavicular region, upper abdomen and renal region, and systolic pressure difference between the two upper limbs greater than 10 mmHg. 3.Clinical classification According to the lesion site, there are four types (1) Cephalobrachial artery type (aortic arch syndrome); thoracic and abdominal aortic type; extensive type and pulmonary artery type. (1) Cephalobrachial artery type (aortic arch syndrome) Narrowing and occlusion of carotid and vertebral arteries can cause different degrees of cerebral ischemia, dizziness, vertigo, headache, memory loss, black spots in unilateral or bilateral vision, vision loss, visual field reduction or even blindness, chewing muscle weakness and chewing pain. A few patients have nasal septal perforation, ulceration of palate and auricle, tooth loss and facial muscle atrophy due to local ischemia. Severe cerebral ischemia may result in recurrent syncope, convulsions, aphasia, hemiparesis or coma. Upper limb ischemia may present with unilateral or bilateral upper limb weakness, coldness, aching, numbness and even muscle atrophy. The carotid, radial and brachial arteries may show reduced or absent pulsation (pulseless sign). In about half of the patients, a systolic vascular murmur of secondary or higher level can be heard in the neck or upper clavicle, and a few are accompanied by tremor, but the murmur loudness is not exactly proportional to the degree of stenosis; in mildly stenosed or completely occluded arteries, the murmur is not obvious, and if a collateral circulation is formed, the blood flow through the enlarged and curved collateral circulation can produce a continuous vascular murmur. (2) Thoracic main and abdominal aorta type Due to ischemia, weakness, soreness, cold skin and intermittent claudication appear in the lower extremities, and the symptoms are most obvious especially when the iliac artery is involved. Hypertension occurs with renal artery involvement, and there may be headache, dizziness, and palpitations. In combination with pulmonary artery stenosis, palpitations and shortness of breath occur, and angina pectoris or myocardial infarction occurs in a few patients. Hypertension is an important clinical manifestation of this type, especially the diastolic blood pressure increase is obvious, mainly renal vascular hypertension caused by renal artery stenosis; in addition, severe stenosis of the thoracic descending aorta, so that most of the blood discharged from the heart to the upper extremities can cause segmental hypertension; systolic hypertension caused by aortic valve closure insufficiency, etc. In simple renal vascular hypertension, the systolic blood pressure in the lower extremities is 20-40 mmHg higher than that in the upper extremities. In some patients, systolic vascular murmurs can be heard on both sides of the parasternal or dorsal spine, and the location of the murmur can help determine the location and extent of aortic stenosis. In approximately 80% of patients, a high pitched systolic vascular murmur of grade II or higher can be heard in the upper abdomen. If combined with aortic valve insufficiency, a diastolic blowing murmur can be heard in the aortic valve area. (3) Extensive type With the characteristics of the above two types, it is a multiple lesion, and most patients have severe disease. (4) Pulmonary artery type The combination of pulmonary artery involvement is not uncommon, accounting for about 50% of the cases. Pulmonary hypertension is mostly a late complication, accounting for about 1/4 of cases, and is mostly mild or moderate, while severe cases are rare. Palpitations and shortness of breath are more often seen clinically. In severe cases of cardiac failure, systolic murmurs and hyperactive second pulmonary valve sounds can be heard in the pulmonary valve area, and the breath sounds are diminished on the side with more severe pulmonary artery stenosis. 4.Laboratory tests No specific blood test items. (1) Erythrocyte sedimentation rate is an important index to reflect the activity of the disease. The sedimentation rate increases when the disease is active and returns to normal when the disease is stable. (2) C-reactive protein, which has the same clinical significance as sedimentation, is one of the indicators of the disease activity. (3) The increase of anti-streptococcal hemolysin “O” antibody only indicates that the patient had a recent hemolytic streptococcal infection, and only a small number of patients have a positive reaction in this disease. (4) Anti-tuberculin test Our data suggest that about 40% of patients have active tuberculosis and should be treated with anti-tuberculosis if active foci are found. Patients with a strong positive reaction to tuberculin should be examined carefully, and if the possibility of tuberculosis is confirmed, anti-tuberculosis treatment should also be administered. (5) Others A few patients have increased white blood cells or increased platelets during the active phase of the disease, also as a reaction to inflammatory activity. Chronic mild anemia may occur, and hyperimmunoglobulinemia is relatively uncommon. Imaging (1) Color multispectral ultrasonography The aorta and its major branches can be investigated for stenosis or occlusion (carotid artery, subclavian artery, renal artery, etc.), but it is more difficult to investigate its distal branches. (2) Angiography ① Digital subtraction angiography (DSA) is a digital image processing system, which is a better screening method. The advantages of this method are easy operation, short examination time, low burden to patients, high contrast resolution, and the ability to show lesions in low contrast areas. The disadvantage of this method is that the small arteries in the organs, such as the branches of the small arteries in the kidneys, are not clearly shown, and selective arteriography is still needed when necessary. Arteriography can directly show the lumen changes of the involved vessels, the size of the diameter, whether the walls are smooth, the extent of the affected vessels and the length of the involved vessels. (3) Electronic computer scan (CT) Enhanced CT can show the lesions of some of the involved vessels, especially MRI can show the edema of the walls of the involved vessels to help determine whether the disease is active. The diagnosis is not difficult for women under 40 years of age with one or more of the following manifestations. (1) Ischemic symptoms in unilateral or bilateral limbs, manifested by weakened or absent arterial pulsation and reduced or undetectable blood pressure. (2) Symptoms of cerebral artery ischemia, manifested by weakened or absent unilateral or bilateral carotid artery pulsations, and cervical vascular murmurs. (3) Recent onset of hypertension or intractable hypertension with a second-degree or higher high-pitched vascular murmur in the upper abdomen. (4) Unexplained hypothermia with vascular murmurs heard on both sides of the spine in the back, or in the parasternal and paramedian areas or in the renal area, and abnormal changes in the pulse. (5) Those without pulses and those with fundus lesions. 2.Diagnostic criteria Adopted the 1990 American College of Rheumatology classification criteria: (1) Age of onset ≤ 40 years Age < 40 years at the onset of symptoms or signs. (2) Intermittent movement disorders of the extremities. Weakness, discomfort or worsening of symptoms in one or more extremities during activity, especially in the upper extremities. (3) Weakness of brachial artery pulsation Weakness of brachial artery pulsation on one or both sides. (4) Differential blood pressure >10 mmHg Differential systolic blood pressure >10 mmHg in both upper extremities. (5) Subclavian artery or aortic murmur A murmur is heard in the subclavian artery or abdominal aorta on one or both sides. (6) Arteriographic abnormality Stenosis or occlusion of aortic primary branches or large arteries proximal to the upper and lower extremities, often focal or segmental in nature and not caused by atherosclerosis, fibromuscular dysplasia or similar causes. The disease can be diagnosed if three of the above six items are met. The sensitivity and specificity of this criterion for diagnosis are 90.5% and 97.8%, respectively. Aortitis is mainly differentiated from congenital aortic stenosis, atherosclerosis, thrombo-occlusive vasculitis, leukoaraiosis, polyarteritis nodosa and other diseases. 3. Differential diagnosis (1) Congenital aortic stenosis Most often seen in males, with a high location of vascular murmur, limited to the precordial region and the back, no systemic manifestations of inflammatory activity, and stenosis at specific sites (in the aortic isthmus in infants and at the arterial duct junction in adult types) seen on thoracic aortography. (2) Atherosclerosis Often develops after the age of 50 with other clinical manifestations of atherosclerosis, digital and angiographic help to differentiate. (3) Fibromuscular dysplasia of the renal arteries Most often seen in women, renal arteriography shows stenosis of the distal 2/3 and branches, without manifestations of aortitis. (4) Thrombo-occlusive vasculitis (Buerger’s disease) is a chronic peripheral vascular occlusive inflammatory disease that occurs in young men with a history of smoking. It mainly involves small and medium-sized arteries and veins in the extremities, and is more common in the lower extremities. The manifestations are limb ischemia, severe pain, intermittent claudication, diminished or absent dorsalis pedis artery pulsation, wandering superficial arteritis, and in severe cases, ulceration or necrosis of the extremity, etc. It is generally not difficult to differentiate from aortitis. (5) Polyarteritis nodosa mainly involves small and medium-sized visceral arteries. The presentation is different from that of aortitis. (6) Thoracic outlet syndrome There may be diminished pulsation of the radial artery, and the pulsation varies with head and neck and upper limb activities, and is often accompanied by venous stagnation of the upper limb and neuropathy caused by compression of the brachial plexus nerve. Treatment plan and principles】 About 20% of this disease is self-limiting, and the disease is stable when it is detected. For the presence of upper respiratory tract, lung or other organ infection factors in the early stage of disease onset, effective infection control may be of some significance in preventing the development of the disease. Those with a high suspicion of tuberculosis infection should be treated with concurrent anti-tuberculosis therapy. Commonly used drugs include glucocorticoids and immunosuppressants, which are treated in the same way as other systemic vasculitis treatments. 1. Glucocorticoids Hormones are still the main therapeutic drugs for the activity of the disease, and timely use of the drugs can effectively improve the symptoms and relieve the disease. Generally, oral prednisone 1mg/kg per day, morning dose or divided dose, maintain 3~4 weeks and then gradually reduce the dose, every 10~15 days to reduce the total amount of 5%~10%, usually to normalize the blood sedimentation and C-reactive protein decline as the indicator of reduction, the dose reduced to 5~10mg per day, should be maintained for a long time. If the conventional dose of prednisone is ineffective, it can be changed to other agents, and critical cases can be treated with high-dose methylprednisolone intravenous shock. However, attention should be paid to hormone-induced adverse reactions such as Cushing’s syndrome, susceptibility to infection, secondary hypertension, diabetes, psychiatric symptoms and gastrointestinal bleeding, and long-term use to prevent osteoporosis. 2.Immunosuppressants Immunosuppressants combined with glucocorticoids can enhance the therapeutic effect. The most commonly used immunosuppressants are cyclophosphamide, azathioprine and methotrexate. In critically ill patients, cyclophosphamide and azathioprine are 2~3mg/kg per day. Cyclophosphamide can be shock treated with 0.5~1.0g/m2 body surface area every 3~4 weeks. Methotrexate 5-25mg per week, intravenously or intramuscularly or orally. The efficacy of the new generation of immunosuppressants, such as cyclosporine A, mycophenolate lipid, and leflunomide, has yet to be confirmed. During the use of immunosuppressants, attention should be paid to checking blood and urine routine and liver and kidney functions to prevent adverse reactions (refer to other relevant chapters). 3. Improve blood circulation by vasodilating and anticoagulation Treatment with vasodilating and anticoagulant drugs can partially improve some clinical symptoms due to more obvious vascular stenosis, such as dibazol 20mg 3 times daily, tolazoline 25-50mg, aspirin 75-100mg once daily, dipyridamole (Pansentin) 25mg 3 times daily, etc. Blood pressure should be actively controlled in patients with hypertension. 4.Percutaneous endoluminal angioplasty A new way has been opened for the treatment of aortitis, which has been applied to treat renal artery stenosis and abdominal aorta, subclavian artery stenosis, etc., with better efficacy. 5.Surgical treatment The purpose of surgery is to solve renal vascular hypertension and cerebral ischemia. (1) For severe cerebral ischemia or obvious visual impairment caused by unilateral or bilateral carotid stenosis, artificial revascularization of the aorta and carotid artery, endothelial thrombectomy or cervical sympathectomy are feasible. (2) For severe stenosis of the thoracic or abdominal aorta, artificial revascularization is feasible. (3) For unilateral or bilateral renal artery stenosis, renal autotransplantation or revascularization is feasible, and nephrectomy is feasible for obvious atrophy of the affected kidney. (4) In cases of carotid sinus hyperreflexia causing recurrent syncope, carotid body removal and carotid sinus neurectomy are feasible. (5) Coronary artery bypass grafting or stenting is feasible for coronary artery stenosis. Prognosis】 This disease is a chronic progressive vascular lesion, and most patients have a good prognosis and can participate in light work because of the rich formation of collateral circulation in the affected arteries. The prognosis mainly depends on the degree of hypertension and cerebral blood supply, and active treatment with glucocorticoids combined with immunosuppressants can improve the prognosis. Complications include cerebral hemorrhage, cerebral thrombosis, heart failure, renal failure, myocardial infarction, aortic valve closure insufficiency, and blindness. The main causes of death are cerebral hemorrhage and renal failure.