Key Concepts

• Radiation injury to the colon and rectum can cause significant morbidity, and effects can be seen many years after initial exposure.
• Surgery should be considered the last resort for radiation injury as complications are frequent. Surgical treatment should be individualized and based on symptoms and clinical context.
• Microscopic colitis is a rare cause of non-bloody diarrhea characterized by nonspecific inflammation in the lamina propria with infiltrates of lymphocytes and plasma cells.
• Budesonide is the only evidence-based treatment of microscopic colitis.
• Ischemic colitis results from disruption of blood flow from small vessels and is distinct from mesenteric ischemia. The treatment of ischemic colitis is based on symptom management and patient optimization.
• Long-term complications of ischemic colitis include strictures and chronic ischemia which may be indications for elective surgery in an otherwise medically optimized patient.