Colon vascular malformation
Introduction
Introduction to colonic vascular malformation Colonic vascular disease is one of the important causes of lower gastrointestinal bleeding. It used to be discovered by angiography or surgery. Nowadays, the popularity and development of endoscopy, more and more colonic vascular diseases are diagnosed and treated, and the lesions are often the blood vessels themselves. Abnormality can also be one of the manifestations of certain diseases. The cause is still not very clear. The most widely used is "vascular malformation". basic knowledge Sickness ratio: 0.0001% Susceptible people: no special people Mode of infection: non-infectious Complications: anemia shock
Cause
Cause of colonic vascular malformation
(1) Causes of the disease
At present, the etiology and pathogenesis of gastrointestinal vascular malformation are still not very clear, and may be related to acquired vascular degeneration, congenital vascular dysplasia and chronic mucosal ischemia. Some scholars believe that these patients have congenital potential factors that make the day after tomorrow. Prone to vascular malformation, Boley studied 19 cases of surgically removed colonic vascular malformation specimens, the direct cause of the submucosal vasodilatation changes is chronic, intermittent and mild submucosal venous obstruction, this venous obstruction The influence of intestinal muscle contraction and intestinal wall tension is proportional to the diameter of the intestine and the intra-intestinal pressure, while the colon has a large inner diameter and a high internal pressure (especially the cecum, the sigmoid colon and the rectal internal pressure are high). Under high tension, it is easy to cause submucosal venous return disorder, resulting in varicose veins and telangiectasia, forming submucosal vascular malformation. In addition, Speth et al found gastrointestinal vascular malformation in patients with aortic stenosis, myocardial lesions and Renal failure is prone to bleeding, possibly due to hypoplasia of vascular malformation and mucosal ischemia caused by chronic hypoxia fruit.
(two) pathogenesis
Colonic vascular malformation is inextricably linked to lower gastrointestinal bleeding because the thin-walled veins and capillaries in the vasodilatation zone are distorted, dilated, and even partially vascular and intestinal lumens are only one layer of endothelial cells, and blood flow barriers lead to decreased mucosal resistance. Therefore, bleeding is easy to occur under inflammatory erosion or some mechanical and chemical stimuli. Moore divides it into type 3: type I, vasodilation is common in the elderly, mostly in the right colon, and the main lesion is in the submucosal small artery. The venules are obviously dilated, distorted and deformed. The lesions can penetrate the submucosa and the mucosa is associated with superficial small ulcers. It is the pathological basis of hemorrhage. It can be seen under colonoscopy, but it can not be touched during surgery. Type II, vascular dysplasia mainly occurs. In young people, it can be located in any part of the intestine, with large lesions, which may be seen or touched; type III, hereditary hemorrhagic telangiectasia, which can be located in any part of the gastrointestinal tract, hereditary, family history With skin telangiectasia, the general amount of bleeding is not large, will not cause shock, no positive signs of physical examination, X-ray and endoscopy and other routine examinations are helpless Diagnosis, blind laparotomy most difficult to find bleeding lesions, selective angiography more reliable means of diagnosis-based disease.
Prevention
Prevention of colonic vascular malformation
According to different symptoms, there are different dietary requirements, ask the doctor specifically, and set different dietary standards for specific diseases.
Complication
Complications of colonic vascular malformation Complications anemia shock
Repeated intermittent bleeding can be associated with varying degrees of anemia, and a large amount of bleeding within a short period of time can also cause shock.
Symptom
Colonic vascular malformation symptoms common symptoms shock vascular malformation abdominal pain
Colonic vascular malformation does not have any symptoms under normal circumstances. It only shows blood when bleeding, dark red blood or fecal occult blood positive, repeated intermittent bleeding may be associated with varying degrees of anemia, if a large amount of bleeding within a short period of time can also lead to shock; However, bleeding from colonic vascular malformation is mainly caused by a small amount of bleeding. The duration of bleeding is different. Most of the bleeding can be stopped by itself. There is a certain self-limiting. In the case of colonic inflammation, there will be abdominal pain and other manifestations. Signs of meaning, there are four major characteristics: the length of the disease varies, the elderly can reach more than ten years; repeated bloody stools, generally less bleeding; self-limiting; lack of physical signs.
Examine
Examination of colonic vascular malformations
Repeated intermittent bleeding can be associated with varying degrees of anemia, red blood cells and hemoglobin decline.
Endoscopy
Endoscopic development and continuous improvement of operation technology make endoscopy an important means of diagnosis of colonic vascular malformation. The positive rate can reach 90%. The endoscopic colonic vascular malformation mainly shows small spots, patchy, and branches. Samples or sparks expand the red lesions. The red lesions sometimes show dilated and tortuous vascular textures. The diameter is 0.2 to 1 cm. The boundaries are clear. Most of them are single or multiple. Qi Tengyu et al. Type 3: Type I, flat dendritic, hail-like aneurysm-like, linear and spark-like expansion of telangiectasia; type II, flat or slightly elevated, 1 to 10 mm clear red spot with a clear circular shape or Star, like blood adhesion; type III, marginal bulging lesions such as submucosal tumors, the apex of the bulge is concave, the center is bright red, in patients with colonic vascular malformation and blood, visible under endoscopy The mucosa of the lesion has mild erosion, submucosal hemorrhage, blood clot coverage and even active bleeding; but the colonic vascular malformation and blood, the first colonoscopy because of blood in the intestine, emergency Difficulty in preparation of the intestines, dilatation of the vasoconstriction after hemorrhage, and difficulty in endoscopic diagnosis, especially in the case of major bleeding, endoscopic examination is not possible, and endoscopic guided surgery is performed under conditions of intraoperative surgery. Stop bleeding is valuable.
2. Selective angiography
Angiography is currently a more effective diagnostic method. It has special value for hemorrhagic localization and etiological diagnosis. The method is to use the Seldinger method to puncture the femoral artery cannula for selective mesenteric angiography. The contrast agent is generally 30% to 40%. Glucamine or an equal concentration of non-ionic contrast agent, the speed is 4 ~ 8ml / s, the filming sequence is delayed by 2s, 1 / s × 5, 1/2s × 5, showing the branches of the artery and confirm the presence or absence of vascular malformation of the arterial tip Image features, common imaging features of intestinal vascular malformations can be summarized as:
(1) arteriovenous fistula and arterial phase early manifestation, that is, arteriovenous fistula appears in the early stage of the artery as a "double track sign", indicating that the arteries and veins have communication, causing early veins, appearing in the late arterial phase and early venous phase.
(2) Local abnormalities increase, and the vascular structural disorder is vine-like or chaotic.
(3) Local staining is dense, that is, it occurs in the arterial or parenchymal phase, and the duration is longer. The arterial phase of the diseased bowel segment has a clear contour contrast agent concentration area under the normal bowel segment, suggesting that the bleeding extravasation performance, the essence Concentration of contrast agent staining in the intestinal segment can be strip or flaky.
(4) The venous phase shows that the mesenteric vein of the mesenteric wall is dilated, distorted, and the contrast agent is delayed, suggesting that the submucosal vein is dilated. DSA can shorten the contrast time, use less contrast agent, and improve the contrast quality. However, the arterial test reported that angiography showed signs of bleeding when the amount of bleeding was >0.5 ml/min.
3. Radionuclide scanning
This test is meaningless in showing intestinal vascular malformation, but the radionuclide scan has a reference value for judging bleeding and location when bleeding occurs in intestinal vascular malformation. It can only be displayed when the amount of bleeding is >0.5ml/min. .
Diagnosis
Diagnosis and differentiation of colonic vascular malformation
The diagnosis of colonic vascular malformation mainly depends on colonoscopy and selective angiography; the double enema of barium enema and air sputum is not meaningful for the diagnosis of this disease. Selective angiography and radionuclide imaging scan have certain diagnostic value when bleeding occurs in colonic vascular malformation.
The disease with bleeding symptoms, clinically needs to be differentiated from other bleeding disorders of the lower digestive tract, such as tumors, inflammation, etc.; endoscopic and angiographic should be differentiated from inflammatory diseases.
