There are rare types of IBD, which are summarized below.
The word ‘ischemia’ refers to an inadequate blood flow to a certain part of the body. This lack of blood supply means that not enough oxygen, glucose, and other materials are able to reach the cells to keep them alive and functioning. Ischemic colitis is the disease that occurs when reduced blood flow to the digestive tract causes inflammation and injury, which leads to IBD symptoms. Ischemic colitis typically occurs in the left area of the abdomen, where it causes considerable pain.
The reduced blood flow can come from a problem with the body’s circulation, such as low blood pressure, or localized events that cause reduced blood flow around the intestinal tract, including blood clots and narrowed or blocked blood vessels. However, there is often no identifiable cause.
Treatment often involves intravenous nutrition in order to allow the bowel to rest, which typically resolves the disease within one or two weeks. In some cases, surgery might be necessary.
Diversion colitis is an inflammation of the colon which can occur as a complication of ileostomy or colostomy, often occurring within the year following the surgery.
Diversion colitis often disappears after full healing from the ostomy surgery, but sometimes further anti-inflammatory treatment is necessary.
Radiation enteritis occurs as a complication from radiation therapy, during which radiation of the abdominal area causes irritation and inflammation to the intestine. Physicians take precautions to avoid radiation exposure to the intestine, but sometimes damage does occur.
Many individuals undergoing radiation develop acute radiation enteritis, which is temporary, but some patients develop chronic radiation enteritis, which can last for months or years after radiation treatment. Symptoms include diarrhea, abdominal pain and cramping, rectal bleeding, and nausea.
Treatment involves dietary changes to increase nutrient intake and to allow the bowel to heal, and taking medications to treat diarrhea, pain, and inflammation. If symptoms are severe, it might be necessary for the patient to cease radiation therapy, and possibly undergo surgery.
Microscopic Colitis (Lymphocytic Colitis & Collagenous Colitis)
There are two types of microscopic colitis, so called because the inflammation is too small to detect during colonoscopy, and requires microscope analysis of a tissue sample (biopsy). It is common for physicians to mistake symptoms of microscopic colitis for other conditions, such as irritable bowel syndrome, gastroenteritis, and celiac disease.
Microscopic colitis includes collagenous colitis and lymphocytic colitis. The most common symptoms include abdominal pain and watery diarrhea that is not bloody. Researchers believe that in some cases, non-steroidal anti-inflammatory drugs (NSAIDs) can cause this disease, because ceasing to take these medications can result in symptom resolution.
We still don’t know much about the development, progression, and treatment of these diseases. The key differentiation between collagenous colitis and lymphocytic colitis is that collagenous colitis involves thickening of the sub-epithelial collagen table. Lymphocytic colitis affects females and males equally, but collagenous colitis is more common in women, with approximately 90% of cases affecting females, typically between 50-70 years of age.
Treatment can involve cessation of NSAIDs if the physician believes it could be the cause, and in some cases taking medications, such as 5-ASA, might be necessary.