Radiation Enteritis – Symptoms and Causes
Overview
Radiation enteritis refers to intestinal inflammation that develops during or after radiation treatment. It commonly affects people who receive radiation aimed at the abdomen, pelvis, or rectal area.
This condition is especially prevalent among patients undergoing cancer treatment for tumors in these regions.
Most cases are temporary, with symptoms improving within weeks after completing radiation therapy. However, some individuals develop chronic radiation enteritis that persists long-term or appears months or years after treatment ends.
Symptoms
Radiation therapy to the abdomen or pelvis can cause immediate digestive problems. These issues typically appear during treatment or shortly after.
Common early symptoms include:
- Diarrhea (often begins 1-2 weeks after starting treatment)
- Cramping in the abdomen
- Nausea and vomiting
- Frequent or urgent need to empty bowels
- Bloating and gas
- Rectal pain or bleeding
Most people notice these symptoms improve within 2-3 weeks after radiation therapy ends. These symptoms often develop gradually and may worsen over time.
When to Contact Your Doctor
Contact your healthcare provider if you experience:
- Severe diarrhea (more than 4-6 loose stools per day)
- Blood in your stool
- Fever above 100.4°F (38°C)
- Signs of dehydration (extreme thirst, dry mouth, dizziness)
- Severe abdominal pain
- Inability to eat or drink
- Vomiting that doesn’t stop
Don’t wait for your next scheduled appointment if these symptoms occur.
Causes
Radiation enteritis happens when radiation therapy damages the lining of the small intestine. This condition typically affects people who receive radiation treatment for cancers in the abdomen or pelvis.
The intestines are very sensitive to radiation. When radiation beams pass through the abdomen to target cancer cells, they can also harm healthy intestinal tissue. The small intestine is particularly vulnerable because its cells divide quickly.
Several factors can increase the risk of developing radiation enteritis:
- Radiation Dose: Higher doses and longer treatment periods increase damage risk.
- Treatment Area: Radiation aimed at the abdomen, pelvis, or lower back poses more risk.
- Previous Abdominal Surgery: Prior operations may make tissues more sensitive.
- Chemotherapy: Having chemotherapy at the same time as radiation therapy.
- Health Conditions: Diabetes, high blood pressure, or inflammatory bowel disease.
The damage occurs because radiation creates harmful molecules called free radicals in the body’s tissues. These molecules damage cell DNA and blood vessels that supply the intestines, leading to inflammation, scarring, and reduced blood flow over time.
Complications
Radiation enteritis can lead to several serious problems if not treated properly.
Some patients develop lasting digestive problems months or years after radiation therapy ends. These issues happen because radiation can cause permanent damage to the intestines.
| Symptom | Description |
|---|---|
| Bowel obstruction | Narrowing of the intestine that blocks digestion |
| Chronic diarrhea | Ongoing loose, watery stools |
| Malabsorption | Difficulty absorbing nutrients from food |
| Fistulas | Abnormal connections between organs |
| Weight loss | Due to poor nutrient absorption |
Intestinal blockage can occur when scar tissue forms and narrows the intestinal passage. Malnutrition happens when the damaged intestines can’t absorb nutrients properly. This can cause weight loss, weakness, and vitamin deficiencies.
Some patients experience fistulas, which are abnormal connections between the intestine and other organs like the bladder or skin.
Chronic diarrhea persists in many patients, making daily activities difficult and potentially causing dehydration and electrolyte imbalances.
Bacterial overgrowth in the intestines can happen when normal gut function is disrupted. This leads to bloating, gas, and worsened diarrhea. Blood loss from damaged intestinal tissue can cause anemia, resulting in fatigue and weakness that impacts daily functioning.
