What Is Radiation Enteritis?

Radiation enteritis is an intestinal complication caused by radiation therapy of pelvic, abdominal, and retroperitoneal malignancies. It can affect the small intestine, colon and rectum, so it is also called radiation rectum, colon and enteritis. Radiation diseases are generally classified into acute and chronic based on the size of the radiation dose to the intestine, the length of time, and the onset of the disease. The radiation source is divided into external radiation radiation disease and internal radiation radiation disease according to different internal and external positions of the radiation source. In the early stage, intestinal mucosal cell regeneration is inhibited, and later the arteriolar wall swells and occludes, causing intestinal wall ischemia and mucosal erosion. The intestinal wall causes fibrosis, narrowing or perforation of the intestinal cavity, formation of abscesses, fistula and intestinal adhesions in the abdominal cavity.

Basic Information

nickname: Radiation rectal, colon, enteritis
English name: radiation induced bowel injury
Visiting department: Internal medicine

Common locations: Small intestine, colon and rectum
Common causes: Irradiation dose, time, sensitivity of different parts of the intestine to irradiation, different activity of different parts of the intestine, etc.
Common symptoms: Nausea, vomiting, diarrhea, discharge of mucus or blood, etc.

Causes of radiation enteritis

1. Irradiation dose and time

When the radiation dose in the pelvic region is 4 to 4.5 weeks after the radiation dose is less than 4200 to 4500 rad, the incidence rate gradually increases; if the radiation dose is increased, the incidence rate increases rapidly. It is generally estimated that the incidence rate is about 8% when the exposure exceeds 5000rad within 5 weeks.

2. Different parts of the intestine have different sensitivity to irradiation

Its tolerance is: rectum> small intestine, colon> stomach.

3. Different degrees of activity in different parts of the intestine

Because the distal ileum and distal colon are relatively fixed, they are more vulnerable to radiation damage. Inflammation or postoperative adhesions make the intestine semi-fixed, restricting the movement of the intestine segment, increasing the exposure per unit area of the intestine segment, and increasing the incidence.

4. Hysterectomy

After the total hysterectomy, the rectal exposure was higher than that of the unresected person.

5. Other basic lesions

Patients with arteriosclerosis, diabetes and hypertension already have vascular lesions, which are more likely to cause gastrointestinal damage after irradiation.

Clinical manifestations of radiation enteritis

Generally, the total radiation dose is less than 3000rad. Symptoms occur when the total amount of intra-abdominal radiotherapy exceeds 4000 rad, and if it exceeds 7000 rad, the incidence rate is as high as 36%. Symptoms can appear early in the treatment, shortly after the end of the course of treatment, or months to years after the treatment.

Early symptoms

Due to the nervous system's response to radiation, gastrointestinal symptoms can appear early. Generally appear within 1 to 2 weeks after the start of radiotherapy. Nausea, vomiting, diarrhea, discharge of mucus or bloody stools. Involving the rectum is accompanied by acute stress. Persistent blood in the stool can cause iron deficiency anemia. Constipation is rare. Occasionally low fever. Spastic abdominal pain suggests involvement of the small intestine, sigmoidoscopy reveals mucosal edema and congestion, and severe cases may have erosions or ulcers.

2. Advanced symptoms

The symptoms of the acute phase do not heal or those who have significant symptoms until 6 months to several years after the end of radiotherapy suggest that the lesions will continue and eventually develop fibrosis or stenosis. Symptoms during this period can occur as early as half a year after radiotherapy, and as late as 10 or even 30 years later. They are mostly related to intestinal wall vasculitis and subsequent lesions.

(1) Colon and proctitis often appear 6 to 18 months after irradiation. Symptoms such as diarrhea, blood in the stool, mucus, and post-emergency, thinning of the stool and progressive constipation or abdominal pain may indicate intestinal stenosis. Severe lesions form fistulas with adjacent organs, such as rectal vaginal fistula, and feces are excreted from the vagina; rectal small intestine fistula can occur with chyme mixed with feces and can also cause peritonitis, abdominal or pelvic abscess due to bowel perforation. Intestinal obstruction can occur due to intestinal stenosis and bowel loops.

(2) Intestinal inflammation When the small intestine is severely damaged by radiation, severe abdominal pain, nausea and vomiting, abdominal distension and bloody diarrhea occur. However, the late manifestations are mainly indigestion, with intermittent abdominal pain, fatty diarrhea, weight loss, fatigue, and anemia.

Radiation enteritis examination

Digital rectal examination

In the early stage of radiation enteritis or with less damage, there is no special finding in digital diagnosis. There can also be only anal sphincter spasm and tenderness. Some anterior rectal walls may have edema, thickening, stiffening, and blood stains on the fingers. Ulcers, stenosis, or fistula can sometimes be touched, and rectal vaginal fistula develops in 3% of severe rectal lesions. A vaginal examination at the same time can help with the diagnosis.

2. Endoscopy

Intestinal mucosal congestion, edema, granulomatous changes, and increased fragility can be seen within the first few weeks, bleeding is easy to touch, and the anterior rectum is even worse. Later, there are thickening, stiffening and characteristic capillary dilatation, ulcers, and narrowing of the bowel cavity. The ulcers can be patchy or drill-like in shape and vary in size, often in the anterior rectum wall at the level of the cervix. Rectal stenosis is mostly 8 to 12 cm above the anal margin. Some colon lesions resemble ulcerative colitis. Thickened and hardened mucous membranes and ring-shaped narrow intestinal segments or drilled ulcers with hard edges can be mistaken for cancer if the surrounding narrow vessels are not dilated. A tissue biopsy can help diagnose, but be careful not to puncture.

3.X-ray inspection

Intestinal barium examination can help determine the extent and nature of the lesion. But the signs are not specific. The barium enema showed small, jagged edges of the colonic mucosa, irregular folds, and stiff or cramped intestinal walls. Intestinal stenosis, ulcers, and fistula formation are sometimes seen. A few mucosa at the edge of the ulcer can bulge, and its X-ray sign resembles cancer, and its distinguishing point is the gradual migration between the lesion and the normal intestine without a sharp dividing line, which is different from cancer. The sigmoid colon is lower and folds into a corner. Examination of the small intestine with barium shows that the lesions are often dominated by the terminal ileum. During barium filling, the lumen was irregularly narrowed, and it was pulled into an angle due to adhesion, forming a thorn-like shadow, thickening the bowel wall, and widening the bowel space. Intestinal nodule-like filling defects can also be seen, similar to inflammatory bowel disease. The normal feathery mucosa of the small intestine disappeared upon emptying.

Determination of small intestinal absorption function: including fecal fat measurement, vitamin B12 and D-xylose absorption test.

Radiation enteritis diagnosis

The diagnosis of this disease is generally not difficult. With a history of radiotherapy combined with clinical manifestations and related examinations, the nature and location of the lesion can be determined, and the diagnosis can be confirmed. X-ray barium examination, mesenteric angiography, endoscopy, and biopsy are needed to identify the advanced manifestations of radiation enteritis and cancer recurrence and metastasis. Other diseases such as non-specific ulcerative colitis, Crohn disease, intestinal tuberculosis, and intestinal lipid metabolism disorder syndrome (Whipple syndrome) should be considered in the differential diagnosis.

Radiation enteritis treatment

General treatment

The acute phase should rest in bed. The diet is based on the principles of no stimulation, easy digestion, rich nutrition, and frequent meals. Limit fiber intake. Severe diarrhea can be treated with intravenous hypertrophic therapy.

2. Medical treatment

(1) Convergence and antispasmodic aspirin can effectively control early diarrhea of radiation enteritis, which may be related to the inhibition of prostaglandin synthesis.

(2) Local analgesics and fecal softeners For those with significant anxiety and pain, 2% benzocaine cottonseed oil can be used to retain the enema. Use warm paraffin oil to retain the enemas or warm water for a bath.

(3) hormone enemas succinyl hydrocortisone warmed saline retention enemas, especially effective for those with severe acute stress .

(4) Anterior closure therapy.

(5) Hemostasis Low bowel hemorrhage can be oppressed under direct endoscopic vision or hemostatic agents or bleeding points can be used to make "8" sutures to stop bleeding. But can not do burning to stop bleeding. Higher bleeding points can be diluted with norepinephrine g or neoforin in 200ml warm saline to retain the enemas, or thrombin can be added to 200ml warm saline to retain the enemas. Generally, hemostasis can be stopped within 1 to 3 minutes. Large amounts of uncontrollable high-level bleeding require surgical treatment.

(6) Anti-infection If there is a secondary infection, antibiotics are needed.

(7) 2 macroglobulin 2 macroglobulin has been used in China to treat radiation enteritis with good results. Mucosal bleeding and pain improved significantly after treatment. The ulcer tends to heal.

3. Surgical treatment

Intestinal stenosis, obstruction, fistula and other late lesions require surgical treatment.

4. Chinese medicine treatment

Traditional Chinese medicine believes that the early gastrointestinal reaction is the loss of body fluids and heat in the stomach and intestines after radiation exposure. Symptoms include nausea, vomiting, and decreased appetite. Expelling yin and stomach. Medicinal rotunda flowers, replacing vermiculite and reversing vomiting; Adenophora chinensis, Yuzhu, and reed roots for nourishing yin and clearing heat; orange peel, bamboo rut, barley kernels, phlegm and stomach. In addition, it can also cooperate with acupuncture at Neiguan and Zusanli.

The prognosis of radiation enteritis is worse than that of radiation colon and proctitis. 2/3 of mild patients can be improved or cured within 4 to 18 months. Some people think that extensive pelvic surgery, such as reradiation, will have a poor blood supply to the diseased tissue, and its prognosis is often poor.

Radiation Enteritis Prevention

You should avoid eating foods with more cellulose or irritation to the intestinal wall. Foods with less residue, low fat and less gas should be eaten. Such as carrots, spinach, etc., both moisturize the intestines and supplement vitamins. Should also pay attention to keeping the anus and perineum clean, wear loose underwear. For severe symptoms, radiotherapy can be suspended, and large doses of vitamins and infusions are used to supplement various intravenous nutrition and adrenocortical hormones and antibiotics to reduce local inflammatory reactions and promote recovery.