Takayasu arteritis, also known as Takayasu disease or pulseless disease, refers to chronic, multifocal, nonspecific inflammation of the aorta and its branches, which results in stenosis or occlusion of the affected arteries. This condition primarily affects young individuals, with a higher prevalence in females.
Etiology and Pathology
The precise cause of Takayasu arteritis remains unclear, though it has been associated with the following factors:
- Autoimmune Reaction: Most researchers consider this condition an autoimmune disease. It may be triggered by infections (e.g., Streptococcus, Mycobacterium tuberculosis, or Rickettsia), which activate antigens in the aortic wall. This leads to the production of autoantibodies against the aorta, the formation of immune complexes, and their deposition in the aortic wall, resulting in a nonspecific inflammatory reaction.
- Estrogen Excess: The condition predominantly affects young women, and arterial wall damage in individuals receiving long-term estrogen therapy has been found to resemble that seen in Takayasu arteritis.
- Genetic Factors: There have been reports of familial clustering (e.g., mother-daughter or sister-sister cases), suggesting an association with certain dominant genetic factors.
The primary pathological feature involves a transmural inflammatory reaction in the arterial wall, which occurs in a segmental distribution. In the early stages, pathologic changes include periarteritis and adventitial inflammation, with infiltration of plasma cells and lymphocytes, destruction of muscular and elastic fibers, associated fibrosis, intimal edema and hyperplasia, and granuloma formation. Progression leads to fibrosis of the arterial wall, irregular luminal narrowing, and secondary thrombosis, which may ultimately result in complete occlusion.
Clinical Manifestations
During the early or active phase of the disease, symptoms such as low-grade fever, fatigue, muscle or joint pain, vascular pain in the affected arteries, and erythema nodosum may occur, along with abnormal immune markers. In the stable phase, arterial narrowing or occlusion develops, leading to specific clinical presentations. Based on the location of arterial involvement, the condition can be divided into the following four types:
Head and Arm Type
Involvement occurs in the aortic arch and may affect one or more branches of the arch. The main clinical manifestations include:
- Cerebral ischemia: Episodes of transient blindness, dizziness, or in severe cases, aphasia, seizures, or hemiplegia.
- Ocular ischemia: Symptoms such as blurred vision or hemianopia.
- Basilar artery ischemia: Symptoms include dizziness, tinnitus, difficulty swallowing, ataxia, and in some cases, disturbances of consciousness.
- Upper limb ischemia: Weakness, numbness, and diminished or absent pulses in the brachial and radial arteries of the affected arm. Blood pressure in the affected arm decreases significantly, often to the point where it cannot be measured, earning the disease the moniker "pulseless disease."
Thoracoabdominal Aorta Type
Involvement occurs in the descending aorta distal to the left subclavian artery and in the abdominal aorta. Both long-segment and localized stenosis or occlusion can occur. The primary feature is the separation of blood pressure between the upper and lower halves of the body. Hypertension affects the upper body, resulting in symptoms such as dizziness, head distension, headache, and palpitations, while the lower body experiences hypotension, with symptoms such as coldness, weakness in the legs, and intermittent claudication. Involvement of visceral arteries leads to organ-specific ischemic symptoms. When the renal arteries are affected, persistent hypertension becomes the primary clinical manifestation.
Mixed Type
This type involves both head and arm as well as thoracoabdominal arterial lesions, producing corresponding clinical symptoms.
Pulmonary Artery Type
Some individuals may exhibit involvement of one or both pulmonary arteries. Typically, this is detected during physical examination, with findings such as a systolic murmur in the pulmonary artery area. Severe cases may present with symptoms such as exertional dyspnea, paroxysmal dry cough, and hemoptysis.
Examination and Diagnosis
In young patients, particularly females, with a history of low-grade fever, fatigue, or joint pain, the diagnosis of Takayasu arteritis should be considered if any of the following clinical manifestations are observed:
- Weakness in one or both upper limbs, diminished or absent pulsations in the brachial and radial arteries, significantly reduced or unmeasurable blood pressure in the upper limbs, with normal lower limb pulsations and blood pressure.
- Diminished or absent pulsations in one or both carotid arteries, accompanied by transient cerebral ischemia symptoms and vascular murmurs heard over the carotid regions.
- Diminished pulsations in the femoral artery and its distal branches, with vascular murmurs audible in the upper abdomen.
- Persistent hypertension, with vascular murmurs audible in the upper abdomen or back.
Auxiliary Examinations
Laboratory Tests
There are no specific markers. During the active phase, findings may include reduced red blood cell counts, elevated white blood cell counts, decreased serum albumin, increased globulin levels, elevated erythrocyte sedimentation rate, and multiple abnormal immune indicators (e.g., increased antistreptolysin O titers, elevated C-reactive protein, positive rheumatoid factor, anti-aortic antibodies, and Coombs antibodies).
Imaging Studies
Doppler ultrasound, CTA, and MRA can demonstrate the location and severity of arterial stenosis.
Angiography
This provides definitive visualization of the location, extent, severity, and type of arterial involvement, as well as the development of collateral circulation.
Specialized Examinations
If arterial disease impacts certain organs, additional tests such as ECG, cardiac ultrasound, cerebral blood flow studies, cranial CT, radionuclide renal imaging, renin activity measurement, fundoscopic vascular examinations, and radionuclide lung scans may be performed.
Differential Diagnosis
Takayasu arteritis should be differentiated from the following conditions:
- Congenital Aortic Stenosis: More common in males, with stenosis often located near the ligamentum arteriosum in a circular pattern. Murmurs are heard along the left upper sternal border, without involvement of other arteries.
- Atherosclerotic Occlusive Disease: Primarily affects middle-aged and elderly individuals, more commonly males, involving large and medium-sized arteries. Associated conditions may include hypertension, hyperlipidemia, and diabetes mellitus. Late stages may result in limb gangrene.
- Thromboangiitis Obliterans: More frequently seen in young males with a history of smoking. Lesions predominantly affect lower extremity blood vessels and often result in distal limb gangrene.
- Thoracic Outlet Syndrome: Caused by structural abnormalities at the thoracic outlet compressing the subclavian artery, subclavian vein, or brachial plexus. Symptoms include coldness and weakness in the affected upper limb, diminished radial pulses, and prominent brachial plexus compression symptoms, such as radiating pain and sensory abnormalities in the upper limb.
Treatment
During the early or active phase of Takayasu arteritis, glucocorticoids and immunosuppressants can control inflammation and alleviate symptoms. However, symptoms may recur after discontinuation of therapy. Patients with arterial ischemic symptoms may take vasodilators or antiplatelet agents such as dipyridamole or aspirin to prevent secondary thrombosis and its propagation. Antihypertensive drugs are necessary in patients with hypertension.
If significant arterial stenosis or occlusion develops, leading to typical symptoms of cerebral ischemia, insufficient blood supply to the limbs, or severe hypertension, surgical treatment may become necessary. Surgical intervention is ideally performed after the inflammatory phase has been controlled and before organ function deteriorates.
Surgical Options
Percutaneous Transluminal Angioplasty (PTA)
This approach has been applied successfully to treat stenosis in renal arteries, carotid arteries, and subclavian arteries. Balloon dilation is widely used, but stent placement should be approached cautiously due to the nature of arterial inflammation.
Open Surgical Treatments
Techniques such as patch angioplasty or bypass grafting are commonly employed. For certain cases of renal artery stenosis, autologous kidney transplantation may also be considered.