Acute radiation enteritis is transient intestinal inflammation and irritation during or after a course of radiation therapy (RT). Occurring in approximately 75% of patients in RT treatment for abdominal / pelvic cancers, common signs and symptoms include nausea, emesis, abdominal pain, tenesmus, hematochezia, and diarrhea. This occurs because RT preferentially targets rapidly dividing cells, including tumors but also the intestinal mucosa.

Onset of acute radiation enteritis is typically 2-3 weeks after starting RT. Symptoms usually resolve 2-6 weeks after completion of RT. Approximately 5%-15% of patients will develop chronic radiation enteritis, which can lead to debilitating complications months or years after RT.

Management begins with prevention techniques to limit the field of radiation exposure during therapy. Treatment is largely supportive (eg, antiemetics). If diarrhea is considerable and leads to dehydration, hospitalization for IV fluids and possibly parenteral nutrition may be necessary.