Which arteries are primarily affected by Takayasu arteritis? Is it related to infection?

Author: Li Taotao, deputy chief physician, Beijing Anzhen Hospital, Capital Medical University

Reviewer: Pan Lili, Chief Physician, Beijing Anzhen Hospital, Capital Medical University

Takayasu arteritis is an autoimmune disease that occurs frequently in young Asian women and primarily affects the aorta and its primary branches.

The largest artery in the human body is the aorta. From top to bottom, the branches that emanate from the aortic arch are the left subclavian artery and the left common carotid artery on the left. The right side is the brachiocephalic trunk, which branches out the right subclavian artery and the right common carotid artery. The branches in the abdomen include the celiac trunk, the superior mesenteric artery, the inferior mesenteric artery, and the left and right renal arteries. Further down, the aorta is divided into the left and right iliac arteries. All of the above are possible sites affected by Takayasu arteritis, and both the aorta and its branches can be affected.

Figure 1 Original copyright image, no permission to reprint

There are also some special ones, such as the coronary artery, which originates from the aorta. The aortic root directly divides into the left and right coronary arteries. In fact, it is also a primary branch of the aorta. Some patients will also have coronary artery involvement. Secondly, the pulmonary artery is also a part that is easily affected by large arteritis.

Generally speaking, Takayasu arteritis does not usually involve the venous system, but in rare cases of extremely severe inflammation, reactive inflammation may occur in certain venous sites. This reactive inflammation is not a direct inflammation of the vein itself, but rather a reactive proliferation and inflammation of the vein or lymph nodes induced by inflammation of the adjacent artery.

Like other autoimmune diseases, the cause of Takayasu arteritis is unclear. It has been found that human leukocyte antigen HLA-B52 is closely related to Takayasu arteritis and is a susceptibility gene.

Takayasu arteritis may also have a certain relationship with estrogen, but there is no conclusion, it is just speculation.

In addition, Takayasu arteritis may be associated with infection, but this association does not mean that infection directly causes vascular inflammation, but rather stems from the immune response produced by the human body in response to infection by pathogenic microorganisms. Under normal circumstances, this immune response is part of the body's defense mechanism. However, when the immune response is excessive, it may cause damage to organs. For example, when the body is infected with pathogenic microorganisms, some of its components (such as proteins) may be similar to those on the aortic wall, causing the immune system to mistakenly attack the aorta while clearing the pathogenic microorganisms. This may also be a mechanism for the onset of Takayasu arteritis.

In general, the root cause of Takayasu arteritis lies in the abnormality of the immune system. The combined action of susceptibility genes and external factors such as infection contributes to the occurrence of the disease.

The classification of Takayasu arteritis is mainly based on its anatomical location, among which the most commonly used is the Japanese Numano classification. This classification is relatively complex, and the following is a brief introduction:

The aorta has three branches at the aortic arch, namely the left carotid artery, the left subclavian artery and the brachiocephalic trunk. If only the three branches from the aortic arch are affected, it is called type I; if the ascending aorta and the branch arteries of the neck are affected, it is called type IIa. If the branches of the aorta neck are affected, and the ascending aorta and the descending aorta are also affected, it is called type IIb; if both the thoracic aorta and the descending aorta are affected, it is called type III; if only the abdominal aorta and/or the renal artery are affected, it is called type IV; if the entire aorta is affected, it is called type V, which is the most common type.

At present, the patients with Takayasu arteritis found in our country are mainly type V, which may be related to the fact that Takayasu arteritis is not easy to be discovered in the early stage. The earliest onset mainly affects the aortic arch, also known as aortic arch syndrome, which can lead to pulselessness. The carotid artery is an artery that supplies blood to the brain. If it is affected, the carotid artery will be occluded, especially if both sides are occluded, and cerebral infarction may be the first symptom. Some patients may first have subclavian artery involvement. Taking the left subclavian artery as an example, it supplies blood to the left upper limb. If the left subclavian artery is narrowed or occluded, the first symptom may be a weakening or disappearance of the left pulse, or unequal blood pressure on both sides. Abdominal blood vessels are affected, such as the mesenteric artery. Due to vascular inflammation, the lumen is occluded, leading to intestinal ischemia, and abdominal pain, nausea, vomiting and other manifestations may occur. Affecting the renal artery can cause stubborn hypertension. Some patients have severe inflammatory reactions and systemic symptoms, such as fatigue and fever, and come to the doctor for fever.

Figure 2 Original copyright image, no permission to reprint

The symptoms of Takayasu arteritis are diverse due to the different sites of blood vessel involvement. Therefore, there is no uniform symptom presentation, and the clinical manifestations of each patient may be different.

As a chronic disease, Takayasu arteritis has no cure yet. However, if it is detected in the early stages and receives active and regular treatment, combined with regular follow-up, the disease can be effectively controlled.

Treatment strategies mainly include symptomatic treatment, medical treatment and surgical treatment, among which medical treatment occupies a dominant position. The most commonly used drug combination for medical treatment is glucocorticoids and immunosuppressants. If the blood vessels of important organs are affected and severe conditions such as stenosis or occlusion occur, surgical intervention and revascularization treatment should be considered.