Ischemic colitis

　　There are many causes of ischemic colitis, which can be generally divided into two major categories: vascular occlusion type and non-vascular occlusion type. Specifically, they are as follows:

　　1. Vascular obstruction type of colonic ischemia.In vascular obstruction type of colonic ischemia, common causes include trauma to the mesenteric artery, mesenteric vascular thrombosis or embolism, and ligation of the inferior mesenteric artery during abdominal aortic reconstruction surgery or colonic surgery.

　　2. Non-vascular obstruction type of colonic ischemia.Mostly spontaneous, usually not accompanied by obvious vascular obstruction, and it is difficult to find a clear cause of colonic ischemia in clinical practice. Most of the patients are elderly, and after the occurrence of colonic ischemic changes, the vascular abnormalities shown by mesenteric angiography may not be consistent with the clinical symptoms.

　　There are many reasons that can trigger spontaneous colonic ischemia, among which hypotension caused by various reasons is the most common, such as septic shock, cardiogenic shock, anaphylactic shock, neurogenic shock, etc., accompanied by cardiovascular disease, hypertension, diabetes, and taking drugs that can affect visceral blood flow (such as antihypertensive drugs, etc.), which can significantly increase the chance of colonic ischemia. A decrease in mesenteric blood supply causes colonic ischemia; while a large range of acute mesenteric blood supply obstruction can also cause a significant decrease in cardiac output, thus leading to a恶性循环 of mesenteric ischemia.

　　Ischemic colitis is often accompanied by a history of hypertension, arteriosclerosis, cardiovascular disease, shock, and long-term medication. Severe cases may develop intestinal wall necrosis, perforation, or persistent intestinal ischemia. Specifically, as follows.

　　1. Intestinal obstruction

　　In the early stage of necrotizing ischemic colitis, in patients with extensive lesions due to severe acute ischemia of the colon, paralytic ileus may occur; while in patients with chronic ischemic colitis, due to fibrous tissue proliferation and scar formation during the chronic inflammatory process, the intestinal lumen may become narrow, leading to incomplete intestinal obstruction.

　　2. Shock

　　In necrotizing ischemic colitis, due to the large absorption of necrotic tissue and bacterial toxins, the microcirculatory vessels are widely open, and the effective blood volume is insufficient, which may lead to hypovolemic and/or toxic shock in patients.

　　The clinical manifestations of ischemic colitis are related to many factors, including etiology, degree of mesenteric vascular obstruction, low blood flow state, size of the obstructed vessel diameter, time and degree of colonic ischemia, speed of onset of ischemic process, compensatory function of collateral circulation, general circulatory status, metabolic status of the intestinal wall, the role of bacteria in the intestinal lumen, and whether there is colonic dilation, etc. Specifically, as follows:

　　1. Abdominal pain, diarrhea, and hematochezia are the most common clinical manifestations. Most patients are over 50 years old and have no obvious precipitating factors. The location of abdominal pain is mostly consistent with the site of colonic ischemic lesions, and it is usually a sudden onset of severe abdominal pain,呈痉挛性发作, lasting for several hours or days, followed by diarrhea with a small amount of blood in the stool. Severe patients may have dark red or bright red stools, accompanied by nausea, vomiting, abdominal distension, and an increase in body temperature, total blood leukocyte count, and neutrophils. Abdominal examination may reveal active bowel sounds in the early stage of the disease or in patients with non-necrotizing colitis, tenderness in the abdominal region of the lesion, and blood stains on the gloves during rectal examination.

　　2、在非坏疽型患者，缺血性结肠炎常为自限性，多数病人随着侧支循环供血的建立，肠黏膜水肿逐渐吸收，黏膜损伤修复，症状在数天内好转，腹痛、腹泻和血便逐渐消失。如果肠壁缺血较重，溃疡愈合需较长时间，腹痛消失后，腹泻和便血可持续数周，但无加重趋势。由于一过性缺血性结肠炎患者病程比较短，临床表现比较轻，许多患者在发病时由于各种原因没有行纤维结肠镜检查，误诊率很高，大部分患者是在回顾病史时，排除了其他结肠病变，例如感染性结肠炎、克罗恩病、溃疡性结肠炎、假膜性结肠炎、结肠憩室病后得以诊断的。

　　2. In non-gangrenous patients, ischemic colitis is often self-limiting. Most patients see an improvement in symptoms within a few days as collateral circulation is established, edema of the intestinal mucosa gradually resolves, mucosal injury is repaired, and symptoms gradually disappear. If intestinal ischemia is severe, ulcer healing may take longer, and diarrhea and hematochezia may persist for several weeks after abdominal pain subsides, but without a tendency to worsen. Due to the relatively short course and mild clinical manifestations of transient ischemic colitis, many patients do not undergo fiberoptic colonoscopy at the time of onset for various reasons, resulting in a high rate of misdiagnosis. Most patients are diagnosed only after excluding other colon diseases, such as infectious colitis, Crohn's disease, ulcerative colitis, pseudomembranous colitis, and colon diverticulosis, when reviewing their medical history.

　　3. Most patients with gangrenous ischemic colitis are elderly with poor general condition, often accompanied by other chronic diseases. Patients with ischemic colitis occurring after abdominal aortic surgery may also be gangrenous. Due to the difficulty in distinguishing the early postoperative clinical manifestations caused by the surgery itself from those of ischemic colitis, diagnosis is difficult and the rate of misdiagnosis is high. Most gangrenous ischemic colitis cases have an acute onset, severe abdominal pain, accompanied by severe diarrhea, hematochezia, and vomiting. Due to toxin absorption and bacterial infection, patients often have significant fever and increased white blood cell count, and may present with obvious peritoneal irritation signs early. Patients with extensive lesions may also have significant paralytic ileus, colon distension, increased intraluminal pressure, and compression of the intestinal wall, further aggravating intestinal ischemia. At the same time, the reduction in effective blood volume and the absorption of toxins can induce shock, further obstructing blood supply to the intestinal wall, leading to intestinal wall necrosis and perforation, and presenting with symptoms such as high fever, persistent abdominal pain, and shock, which are indicative of peritonitis. Most patients with gangrenous ischemic colitis are diagnosed only when laparotomy is performed due to strangulated intestinal obstruction or peritonitis.

　　How to prevent ischemic colitis? The following is a brief introduction:

　　1. It is important to maintain a regular diet, with three meals a day at fixed times and amounts, avoiding excessive hunger and overeating. This is beneficial for intestinal digestion balance and prevents intestinal dysfunction caused by uncontrolled eating.

　　2. The diet should be light, easy to digest, and low in greasiness. It is advisable to eat健脾 foods such as yam, white adzuki bean, lotus seed, lily, jujube. Eat less cold drinks and foods that are easy to cause bloating, such as watermelon, honeydew melon, leek, onion, garlic, fried foods, coffee, carbonated drinks, etc.

　　3. Eat less high-fat foods to avoid increasing the burden on the gastrointestinal tract due to difficult digestion, such as high-fat fast food.

　　4. Avoid excessive alcohol consumption.

　　The examination of this disease shows an increased white blood cell count in the blood routine; red and white blood cells can be seen in stool routine; colonoscopy shows congestion, edema, and brown mucosal necrotic nodules in the intestinal mucosa; biopsy shows varying degrees of submucosal necrosis, hemorrhage, granulation tissue, fibrosis, or hyaline change, etc.; early barium enema shows slight dilation of the colon, and there may be a typical finger pressure sign. Specifically as follows.

　　1. Blood routine:Elevated white blood cell count and neutrophils.

　　2. Histopathological examination:Macerated necrosis and ulceration of the colonic mucosa can be seen with the naked eye, or complete necrosis of the mucosa, and microscopic examination shows hyperplastic capillaries, fibroblasts, and macrophages under the mucosa.

　　3. Rectal examination:Bloodstains are often visible on the gloves.

　　4. X-ray film:The abdominal X-ray film shows dilation of the colon and small intestine,紊乱 of the colon loops, some patients may have colonic spasm and narrowing; in some cases of gangrenous ischemic colitis, free gas in the peritoneal cavity caused by colon perforation and gas in the intestinal wall and portal vein caused by progressive ischemia of the intestinal wall and increased permeability of the intestinal wall may be seen.

　　5. Barium enema examination:This examination can provide a comprehensive understanding of the extent of the lesion, especially the range of the lesion, but there is a risk of causing colonic perforation, so it should be used with caution for patients with severe illness, a large amount of blood in the stool, and suspected intestinal necrosis.

　　6. Fiberoptic colonoscopy:Fiberoptic colonoscopy is the most effective examination method for diagnosing ischemic colitis. When a patient is suspected of having ischemic colitis but does not have signs of peritonitis, and there are no obvious signs of colonic obstruction or perforation in the abdominal X-ray film, endoscopic examination should be considered.

　　7. Mesenteric arteriography:Since the artery occlusion site in most patients with ischemic colitis is in small arteries, it is difficult to find signs of artery occlusion in mesenteric arteriography. In addition, due to the possibility of causing further thrombosis, caution should be exercised in its use.

　　8. CT scan:Some patients may show non-specific changes such as intussusception and thickening of the intestinal wall due to intestinal lumen dilation and intestinal wall edema.

　　The dietary therapy for ischemic colitis is described as follows:

　　1. Porridge of Herba Plantaginis, white adzuki bean, and Job's tears:Herba Plantaginis 15g, Lophatherum griseum 9g, dried lotus leaf 9g, white adzuki bean 30g, Job's tears 30g, and glutinous rice 60g. First, decoct Herba Plantaginis, Lophatherum griseum, and dried lotus leaf in water, remove the residue and filter the juice. Then, cook white adzuki bean and glutinous rice with an appropriate amount of water to make porridge, and add the herbal juice to cook together into a thin porridge for consumption. Take 1 day in 2 doses. This product clears heat, relieves dampness, and detoxifies. It can be used for diarrhea with profuse discharge or diarrhea that is not comfortable, yellow and green stools with foul smell, anal heat, restlessness, thirst, and short, dark urine.

　　2. Stewed black chicken with amomum and Angelica sinensis:10g of amomum, 10g of Angelica sinensis, appropriate amounts of scallion whites, ginger, salt, one whole black chicken, monosodium glutamate. Clean the black chicken, remove the internal organs, implant amomum, Angelica sinensis, scallion whites, and ginger into the abdomen, place in a pot, add water, and boil until tender. Add appropriate amounts of salt and monosodium glutamate when eating.

　　The treatment methods for ischemic colitis are briefly described as follows:

　　Firstly, Treatment Principles

　　During treatment, fasting is adopted, and moderate to high-flow oxygen supply is maintained; actively eliminate triggers and treat accompanying diseases; expand blood volume, promote microcirculation, and improve intestinal mucosal ischemia; use antibiotics; improve the overall condition, treat shock, rehydrate, and correct heart failure; treat accompanying diseases and complications; surgical treatment may be necessary if required.

　　Early supportive treatment for pathologic conditions, including fasting, fluid resuscitation, maintaining electrolyte balance, and maintaining cardiac output, can involve the use of antibiotics to prevent infection. In severe cases with signs of intestinal perforation or peritonitis, an early laparotomy should be performed.

　　Secondly, Treatment Methods

　　1. Conservative treatment of most non-gangrenous lesions confined to the intestinal wall has self-limiting properties and can be gradually absorbed. Even if some patients develop colonic stricture, most are incomplete intestinal obstruction, which can be alleviated by conservative treatment.

　　The mortality rate of surgical treatment for gangrenous ischemic colitis largely depends on the timeliness of diagnosis and treatment, the patient's overall condition, and the occurrence of complications. Once severe complications such as respiratory distress syndrome, renal failure, and persistent infection occur, the mortality rate is very high. Surgical treatment is mostly limited to gangrenous patients with ischemic colitis, and surgery should be performed as soon as possible after diagnosis. Patients with gangrenous ischemic colitis accompanied by significant colonic dilation should consider total colectomy. For patients whose condition persists for more than 2 weeks and whose condition does not show significant improvement despite active conservative treatment, surgical treatment should also be considered. Most colonic strictures caused by ischemic colitis are incomplete intestinal obstruction, so surgery can generally be avoided. For patients with chronic colonic obstruction symptoms, surgical treatment should be considered if conservative treatment cannot alleviate the condition or if it is difficult to differentiate from colon malignant tumors, with the aim of resecting the narrowed intestinal segment to reconstruct the continuity of the intestinal tract.