radiation enteritis

Radiation enteritis is an intestinal complication caused by radiotherapy for malignant tumors in the pelvic, abdominal, and retroperitoneal regions. It can involve the small intestine, colon, and rectum separately, and is therefore also called radiation proctitis, colitis, or enteritis. According to the radiation dose to the intestine, duration of exposure, and the acuteness of onset, radiation disease is generally divided into acute and chronic types. It is also classified into external irradiation sickness and internal irradiation sickness based on the location of the radiation source placed inside or outside the body. In the early stage, intestinal mucosal cell renewal is inhibited; subsequently, small arteriole walls swell and become occluded, causing intestinal wall ischemia and mucosal erosion. In the late stage, intestinal wall fibrosis occurs, leading to intestinal stenosis or perforation, with the formation of intra-abdominal abscesses, fistulas, and intestinal adhesions.