Radiation-induced enteritis

Radiation-induced enteritis is a bowel pathology resulting from toxic effects of radiotherapy on the bowel wall and vasculature. 

5-15% of patients treated with radiotherapy (usually > 4500cGy) develop chronic radiation enteropathy.

The clinical presentation is nonspecific with abdominal pain, vomiting, bloody diarrhea and steatorrhea. Patients with chronic radiation enteritis may develop deficiencies of calcium, iron and vitamin B12 deficiency.

In the acute phase, radiation affects bowel mucosa causing cell death with ulceration. It also causes inflammation with mucosal and submucosal edema. In the subacute and chronic phases healing and fibrosis occurs. Additionally, radiation induces endarteritis obliterans, which results in a state of chronic mesenteric ischemia leading to bowel strictures.

  • adhesions from previous abdominal surgery
  • peritonitis prior to radiation therapy
  • high radiation dose
  • risk factors for atherosclerosis; hypertension and diabetes mellitus
  • chemotherapy 
  • acute stage: concurrent or within 2 months of treatment
  • subacute: 2-12 months after treatment
  • chronic: >12 months after treatment
  • acute radiation enteritis
    • bowel loops appear spastic with luminal narrowing and edema of mucosal folds
  • chronic radiation enteritis
    • thickening of bowel wall and folds due to edema or fibrosis
    • “stack of coins appearance” enlarged smooth, parallel mucosal folds
    • single or multiple bowel stenoses
    • ulcers
  • bowel wall thickening and luminal narrowing
  • small bowel obstruction
  • fistulas between the bowel (especially colon) and the bladder or vagina

Following pelvic radiotherapy, enteritis of the small bowel typically involves the more fixed terminal ileum and manifests as bowel wall thickening and submucosal edema at CT. 

General imaging differential considerations include:

As a broader differential consider other forms of enteritis.

Radiation therapy
Share article

Article information

rID: 16271
Tag: cases
Synonyms or Alternate Spellings:
  • Radiation enteropathy
  • Radiation-induced bowel injury
  • Radiation-induced small bowel injury
  • Radiation-induced enteritis

Support Radiopaedia and see fewer ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Case 2
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.