What are the symptoms of radiation enteritis?

The symptoms of radiation enteritis are actually different in the early and late stages. In the early stages, patients often experience nausea, vomiting, diarrhea, or mucus and bloody stools. In the late stages, it may also cause fibrosis and intestinal stenosis.

1. Early symptoms

Gastrointestinal symptoms may appear early due to the nervous system's response to radiation. It usually occurs within 1 to 2 weeks after the start of radiotherapy. Nausea, vomiting, diarrhea, mucus or blood in the stool. Involvement of the rectum is accompanied by tenesmus. Persistent blood in the stool can cause iron deficiency anemia. Constipation is uncommon. Occasionally low fever. Spasmodic abdominal pain indicates involvement of the small intestine. Sigmoidoscopy may reveal mucosal edema and congestion, and in severe cases, erosion or ulcers.

2. Late symptoms

If the acute symptoms persist or do not heal until 6 months to several years after the end of radiotherapy, it indicates that the disease is continuing and will eventually develop into fibrosis or stenosis. Symptoms during this period may occur as early as six months after radiotherapy or as late as 10 or even 30 years later, and are often related to intestinal wall vasculitis and subsequent lesions.

(1) Colon and proctitis: usually occurs 6 to 18 months after irradiation. Symptoms such as diarrhea, blood in the stool, mucus in the stool, tenesmus, narrowing of the stool, progressive constipation, or abdominal pain indicate intestinal stenosis. Severe lesions may form fistulas with adjacent organs, such as rectovaginal fistulas, in which feces are discharged from the vagina. Rectal intestinal fistulas may result in chyme being discharged mixed with feces, and intestinal perforation may also cause peritonitis, abdominal or pelvic abscesses. Intestinal obstruction may occur due to intestinal narrowing and entanglement of intestinal loops.

(2) Enteritis: When the small intestine is severely damaged by radiation, severe abdominal pain, nausea, vomiting, abdominal distension, and bloody diarrhea may occur. However, the main symptoms in the late stage are malabsorption, accompanied by intermittent abdominal pain, steatorrhea, weight loss, fatigue, anemia, etc.