Intestinal mucosa with necrotic ulcer

Introduction The rectal radioactive lesion can be divided into four degrees. The second clinical manifestation is the frequency of stool. There is bloody stool or mucus, and it is heavy and heavy. The symptoms can last for months or years, and the intestinal mucosa has necrosis, ulceration or moderate stenosis. Radiation enteritis is a bowel complication caused by radiotherapy in pelvic, abdominal, and retroperitoneal malignancies. It can affect the small intestine, colon and rectum, so it is also called radioactive rectum, colon, and small intestine. According to the size of the radiation dose, the length of time, and the urgency of the disease, the radiation diseases are generally classified into acute and chronic. According to the position of the radiation source placed in the body and outside, it is divided into external radiation radiation disease and internal radiation radiation disease. In the early stage of intestinal mucosal cell renewal is inhibited, after the small arterial wall swelling, occlusion, causing intestinal wall ischemia, mucosal erosion. Late intestinal wall causes fibrosis, intestinal lumen is narrow or perforated, and abscess, sacral and intestinal adhesions are formed in the abdominal cavity.

Cause

1. Intestinal epithelial cell proliferation is inhibited: intestinal mucosal epithelial cells are most sensitive to radiation. The thymidine-labeled thymine was observed as a cell renewal, and it was found that the regeneration of the intestinal mucosa was completed by the proliferation of undifferentiated cells located in the crypt of the intestinal gland. These cells lose the ability to divide after differentiation and gradually move to the surface of the intestinal mucosa. Radiation inhibits the proliferation of these cells, causing characteristic acute lesions in the intestinal mucosa. If the radiation dose is not excessive, mucosal damage can be restored 1 to 2 weeks after stopping the radiation therapy. Recent studies have found that the effect of multiple exposures depends on the cell cycle in which the crypt cells are exposed. Cells in the late stage of division are most sensitive to radiation, while cells synthesized in the late stage are more tolerant, since only a portion of all proliferating crypt cells at any given time are in a certain phase of the cell proliferation cycle, so single High-dose irradiation only killed a portion of the cells, and after a few days the cells were mitotic and returned to normal.

Second, the intestinal submucosal arteries are damaged: the endothelial cells of the small arteries are very sensitive to radiation. High-dose radiation therapy causes cells to swell, proliferate, and fibrosis, causing occlusive endarteritis and endarteritis, resulting in intestinal wall ischemia and mucosal erosion and ulceration. Bacterial invasion in the intestine further develops the lesion.

Third, intestinal wall tissue damage: intestinal wall tissue caused by extensive continuous irradiation caused by edema, fibroblast proliferation in all layers of the intestinal wall, connective tissue and smooth muscle changes in a transparent manner, and finally lead to fibrosis, intestinal stenosis, mucosal surface distortion And understand, so the intestinal changes caused by radiation can change from reversible mucosal structure until chronic fiber thickening, accompanied by ulcerated intestinal tract, and even cause intestinal obstruction.

an examination

The clinical symptoms of radiation enteritis, the general dose of radiation below 3000rad rarely occur. Symptoms occur when the total amount of intraperitoneal radiotherapy exceeds 4000 rad. If it exceeds 7000 rad, the incidence rate is as high as 36%. Symptoms can occur early in the treatment, shortly after the end of the treatment or months to years after treatment.

First, early symptoms: due to the nervous system's response to radiation, early symptoms of gastrointestinal tract can occur. It usually appears within 1 to 2 weeks after the start of radiotherapy. Nausea, vomiting, diarrhea, discharge of mucus or bloody stools. Those who are involved in the rectum are accompanied by urgency and weight. Long-lasting blood in the stool can cause iron deficiency anemia. Constipation is rare. Occasionally low heat. Sputum abdominal pain suggests small bowel involvement, sigmoid colonoscopy can be seen mucosal edema, congestion, severe cases may have erosion or ulceration.

Second, advanced symptoms: symptoms of acute phase prolonged or until the end of radiotherapy from 6 months to several years after the beginning of significant symptoms, all suggest that the lesion continues, eventually will lead to fibrosis or stenosis. Symptoms during this period can be as early as half a year after radiotherapy, or 10 years later or even 30 years later, and more related to intestinal wall vasculitis and detained lesions.

1. Colon, proctitis: often occurs 6 to 18 months after irradiation. The reported incidence in China is 2.7% to 20.1%. Symptoms of diarrhea, blood in the stool, mucus and urgency, thin stools and progressive constipation or abdominal pain suggest a narrowing of the intestine. Severe lesions and adjacent organs form fistulas, such as rectal vaginal fistula, feces are discharged from the vagina; rectal bladder makeup can appear pneumoconiosis; rectum small intestine fistula can appear in the feces mixed with feces, but also peritonitis caused by intestinal perforation, Abdominal or pelvic abscess. Intestinal obstruction can occur due to narrowing of the intestine and entanglement of the intestines. The radioactive lesion of the rectum can be divided into four degrees: I degree, with no or only mild symptoms, only mild edema of the intestinal mucosa, and can quickly heal itself. These changes are generally considered to be radioactive damage. II degree, frequency of stool, bloody stool or mucus, heavy and heavy, symptoms may last for months or years, necrosis, ulceration or moderate stenosis of intestinal mucosa. III degree, severe rectal stenosis, need to be colostomy. IV degree has been accompanied by the formation of hackers. Some scholars have classified four types of radiation enteritis, namely catarrhal type, erosive desquamation type, infiltration ulcer type, infiltration ulcer with vaginal rectal fistula. Complications of radiation enteritis include knots, rectal cancer, rectal adenocarcinoma, deep cystic colitis, solitary rectal ulcers (mostly in the anterior wall, and also in the latter).

2. Intestinal inflammation: severe abdominal pain, nausea and vomiting, abdominal distension, and bloody diarrhea when the small intestine is severely damaged by radiation. However, the late performance is mainly due to digestive malabsorption, accompanied by intermittent abdominal pain, steatorrhea, weight loss, fatigue, anemia and so on.

Differential diagnosis

Intestinal mucosal shedding: Some intestinal mucosal tissues sometimes appear in normal stools, which are related to the normal metabolic loss of the intestinal mucosa. Intestinal mucosal tissue can also occur when the intestine is stimulated, not digested, or diarrhea. Sometimes, when antibiotics are applied, mucosal shedding can be increased. Intestinal mucosal shedding can be seen in bacterial dysentery. Shigella dysenteria has the ability to invade the colonic epithelial cells of the colon, and can destroy the barrier of the cells, attracting leukocytes to the inflammatory site, and then allowing more dysentery bacilli to settle in the mucosal epithelial cells, causing more serious lesions of the intestinal mucosa, causing the colon Mucosa ulceration, shedding, and bleeding. These shed pus and blood are excreted together with the faeces in the intestine to form a typical mucus pus and dysentery-like stool. The rectal radioactive lesion can be divided into four degrees. The second clinical manifestation is the frequency of stool. There is bloody stool or mucus, and it is heavy and heavy. The symptoms can last for months or years, and the intestinal mucosa has necrosis, ulceration or moderate stenosis.

Increased permeability of gastrointestinal mucosa: more common in gastric cancer and colon cancer due to necrosis of cancer tissue caused by increased permeability of the corresponding gastrointestinal mucosa, a large amount of plasma protein leaked from the gastrointestinal tract. A protein-deprived gastrointestinal disorder can be confirmed by a radionuclide-labeled macromolecular substance digestive tract excretion test, or an 1-antitrypsin test.

Gastric mucosal damage: The entire inner surface of the stomach is covered with a layer of mucosal tissue that secretes mucus, forming a mucous-mucosal barrier of the stomach to protect the stomach tissue. Gastric mucosal injury is more common in gastritis and gastric ulcer. Gastroscopic examination, to observe the color of the gastric mucosa, bleeding points, congestion and erosion damage, compared before and after changes, according to the degree of disease is divided into light, moderate and severe damage. Gastrointestinal contrast-enhanced ultrasonography can clearly show the structural level of the stomach wall and has a certain diagnostic value for acute gastric mucosal injury.

Gastric mucosa shedding: The gastric mucosa is relatively relaxed. When the stomach contracts, the gastric mucosa near the pylorus is removed into the duodenal bulb. The clinical symptoms are symptoms of gastritis. Irregular upper abdominal pain, often accompanied by abdominal distension, belching, nausea and vomiting. Eating can induce or aggravate upper abdominal pain, and upper abdominal pain can be relieved after vomiting. The right lateral position during sleep can aggravate the pain, and vice versa. Taking anti-acid or acid-suppressing drugs is generally ineffective.

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