Inflammatory abdominal aortic aneurysm

　　1. Causes of Disease

　　It is currently believed that the existence of abdominal aortic aneurysm is the initiating factor of an inflammatory process. Almost all atherosclerotic abdominal aortic aneurysms have varying degrees of inflammatory response, and after the removal of inflammatory abdominal aortic aneurysms in clinical practice, the inflammatory response will subside. Some people believe that the compression of abdominal aortic aneurysm on the retroperitoneal lymphatic vessels causes lymphostasis and retroperitoneal edema, stimulating fibrosis; some people believe that inflammatory abdominal aortic aneurysm is a local autoimmune response, which is caused by the leakage of wax in atherosclerotic plaques into surrounding tissues as an allergen; and some people believe that the embolism of the aortic nutrition vessels causes damage to the media, leading to the formation of inflammatory abdominal aortic aneurysm.

　　2. Pathogenesis

　　1. Pathological morphology

　　During surgery, inflammatory abdominal aortic aneurysms often appear white and shiny, and some people call it 'porcelain-like' or 'iceberg-like' changes. The aneurysm is surrounded by obvious fibrosis and is closely adherent to adjacent duodenum, mesentery of small intestine, left renal vein, ureter, inferior vena cava, etc. The lesion can extend to the origin of the superior mesenteric artery and down to the common iliac artery. The anterior and lateral walls of the aneurysm are significantly thickened, while the posterior wall is often not thickened and is relatively thin and can erode adjacent vertebrae, making it a vulnerable site prone to rupture.

　　The histological changes include thickening of the adventitia and media, with the intima often showing obvious atherosclerotic changes. The media and adventitia show acute and chronic inflammatory cell infiltration, including macrophages, most of which are activated T lymphocytes. The media smooth muscle disappears and elastic fibers break, with early granulation tissue proliferation around the adventitia, which includes nerve and vascular components. In the late stage, it can gradually fibrosis and fuse with the media and adventitia to form obvious fibrosis changes.

　　2. Pathological types: According to the morphological characteristics of inflammatory abdominal aortic aneurysms, the pathological types are divided into two types:

　　Type I (fibrotic lesion type): Characterized by marked fibrosis around the abdominal aortic aneurysm, which often leads to the involvement and obstruction of the ureter.

　　Type II (cystic protrusion type): Characterized by localized cystic protrusion of the abdominal aortic aneurysm. It is almost always a pseudo-aneurysm and is more prone to rupture than Type I. The pathological features include inflammatory thickening of the adventitia, infiltration of inflammatory cells, damage to the nutrient vessels, and media rupture.

　　Common complications of this disease include lower limb arterial栓塞, hydronephrosis caused by ureteral compression, and rupture of the abdominal aortic aneurysm. Among them, rupture of the abdominal aortic aneurysm is a major cause of sudden death. Abdominal aortic enteric fistula and abdominal aortic inferior vena cava fistula are rare complications, and the tumor may occasionally adhere to adjacent intestinal tubes.

　　Inflammatory abdominal aortic aneurysms almost always present with symptoms, mainly abdominal and lumbar back pain, and sometimes are misdiagnosed as a ruptured abdominal aortic aneurysm. Patients may experience weight loss and an elevated erythrocyte sedimentation rate. The involvement of the ureter can cause ureteral obstruction, leading to hydronephrosis. In the long term, it can lead to renal function impairment, with elevated blood urea nitrogen and creatinine levels, and even evolve into uremia. The involvement of the duodenum can cause intestinal obstruction, and symptoms may include anemia and loss of appetite. Abdominal palpation may reveal a pulsatile mass. Some people summarize the three clinical manifestations of abdominal aortic aneurysm, ureteral centripetal displacement, and an elevated erythrocyte sedimentation rate as the 'triad' of inflammatory abdominal aortic aneurysms.

　　Firstly, it should be actively prevented from the occurrence of atherosclerosis (primary prevention), if it has occurred, it should be actively treated to prevent the progression of the disease and strive for its reversal (secondary prevention). For those with complications, timely treatment should be provided to prevent their deterioration and to prolong the life of the patients (tertiary prevention).

　　It may have an increased erythrocyte sedimentation rate and anemia, etc., in addition, blood BUN, Cr and renal function tests should be performed.

　　I. X-ray film:The anteroposterior and lateral films of the abdomen can reveal the shell-like calcified shadow of the aneurysm wall, and it is common for inflammatory abdominal aortic aneurysms to have signs of vertebral erosion.

　　II. Ultrasound examination:It can be found that the wall of the abdominal aortic aneurysm is significantly thickened, with a hypoechoic halo in front and on the side, which needs to be differentiated from the hematoma around the aneurysm.

　　III. CT scan:It is of great value for the diagnosis of inflammatory abdominal aortic aneurysm, with a typical manifestation of a ring-like soft tissue density shadow in front and on the side of the calcified wall of the abdominal aortic aneurysm, which is easily misdiagnosed as a hematoma around the abdominal aortic aneurysm. After injection of contrast agent, it can be enhanced, but the density is slightly lower than that of the blood in the aorta, and some people call this manifestation 'Mantlesign'.

　　IV. Intra-venous pyelography (IVP):It can be found that the ureter is eccentrically displaced and/or renal积水 is present, if patients with abdominal aortic aneurysm have this condition, it should be considered as a possible case of inflammatory abdominal aortic aneurysm.

　　V. Aortography:Sometimes, the angle of aortic bifurcation may increase and the irregular shape of the abdominal aortic aneurysm wall may be seen, which is helpful for diagnosis and determining the surgical plan.

　　I. Carbohydrate foods

　　Suitable foods: Rice, congee, noodles, noodle products, konjac powder, soup, taro, soft beans.

　　Food to be avoided: Sweet potatoes (food that produces abdominal gas), dried beans, strong-flavored biscuits.

　　II. Protein foods

　　Beef, lean pork, white meat fish, eggs, milk, dairy products (fresh cream, yeast milk, ice cream, cheese), soybean products (tofu, natto, soybean powder, oil tofu).

　　Food to be avoided: Foods high in fat (beef, pork belly, spareribs, whale, herring, tuna, etc.), processed products (sausage).

　　III. Fatty foods

　　Suitable foods: Vegetable oils, a small amount of butter, salad dressing.

　　Food to be avoided: Animal oils, lard, smoked meats, oil-soaked sardines

　　IV. Vitamin and mineral foods

　　Suitable foods: Vegetables (spinach, cabbage, carrots, tomatoes, lily roots, pumpkins, eggplants, cucumbers); fruits (apples, oranges, pears, grapes, watermelons); seaweeds and mushrooms should be cooked before eating.

　　Food to be avoided: Fibrous and tough vegetables (daikon, bamboo shoots, beans), vegetables with strong刺激性 (spicy vegetables, coriander, rapeseed, scallions, mustard greens).

　　V. Other foods

　　Suitable foods: Lightly scented tea, yeast milk drinks.

　　Food to be avoided: Spicy seasonings (chili, curry powder), alcoholic beverages, salted foods (canned dishes, canned fish eggs).

　　I. Treatment

　　Although inflammatory abdominal aortic aneurysms have fibrosis and thickening of the aneurysm wall, they can still rupture due to the thin posterior wall, and type II is more prone to rupture than type I. The only radical treatment method for inflammatory abdominal aortic aneurysm is surgical resection.

　　I. Surgical treatment

　　Like the excision of an atherosclerotic abdominal aortic aneurysm, replace the abdominal aortic aneurysm with an artificial blood vessel. Due to the close adhesion of the tumor to surrounding organs, the剥离 range should be minimized during surgery to avoid secondary injury. After laparotomy, a white, shiny aneurysm wall can be seen closely adhering to the posterior peritoneum, duodenum, ureter, left renal vein, and other organs, which is easy to diagnose. To reduce stripping, it is currently advocated to block the abdominal aorta above the infradiaphragmatic abdominal artery to avoid circular stripping of the common iliac artery when the distal end is exposed, in order to avoid injury to the iliac vein or inferior vena cava. Some people also use a balloon catheter to block the distal iliac artery to reduce stripping. After blocking the proximal and distal ends of the tumor, excise the abdominal aortic aneurysm and replace it with an artificial blood vessel. There is still controversy about the treatment of the ureter adhering to the aneurysm wall during surgery. If there is pre-existing ureteral obstruction causing hydronephrosis and kidney damage, percutaneous nephrostomy or dialysis treatment should be performed to improve renal function first. Some people believe that the obstruction caused by ureteral adhesion can be relieved after the excision of the abdominal aortic aneurysm, and ureterolysis can increase the difficulty of surgery without this necessity; some people believe that postoperative hormone therapy can cause the adhesion to regress and the obstruction to be relieved; however, some scholars believe that ureterolysis can quickly restore and restore the function of the kidney in patients with hydronephrosis and reduce the recurrence of ureteral obstruction. Therefore, it is currently advocated to use B-ultrasound, CT, or IVP for regular follow-up observation after the operation of inflammatory abdominal aortic aneurysm to detect and treat late ureteral complications in time.

　　II. Hormone therapy

　　Some people believe that hormone therapy after the excision of inflammatory abdominal aortic aneurysm can promote the regression of inflammation and fibrosis, and even propose that hormone therapy can be used instead of surgical treatment except for the enlargement of the abdominal aortic aneurysm or the pre-breakage; however, some people believe that hormone therapy has no definite efficacy and may even lead to rupture, delay wound healing, and cause adverse consequences such as aneurysms at the anastomosis site.

　　The clinical practice is to use hormone therapy as soon as the diagnosis of inflammatory abdominal aortic aneurysm is made, to reduce body temperature and C-reactive protein to normal levels (CRP

　　II. Prognosis

　　There is no relevant content description at present.