Overview of Microscopic Colitis

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Overview of Microscopic Colitis

Microscopic colitis (MC) is a rare (orphan), chronic inflammatory disease of the colon that is thought to be autoimmune in origin. It can only be diagnosed by examining a biopsy specimen of the colon under a microscope. The term MC includes both lymphocytic colitis (LC) and collagenous colitis (CC). Although MC is often diagnosed in middle-aged women, it can affect any age and men as well.

The most common symptoms of MC include diarrhea (often with much frequency and urgency), abdominal pain, and abdominal bloating. Other symptoms and signs, such as fatigue, joint pains, muscle aches, fibromyalgia, and fever, are not unusual. Bloody stools are not a typical characteristic of MC but can be due to related problems such as hemmorhoids, rectal fissure, or infection.

It is thought that MC occurs when the body mistakenly recognizes the "good" bacteria in its colon as foreign and begins to make antibodies to kill it off. This upsets the natural balance of "good vs. "bad" bacteria in the colon, which allows for an overgrowth of "bad" bacteria and leads to chronic inflammation.

What initiates the autoimmune process in the first place? It is believed that there is a genetic component......a gene that makes certain individuals more likely to get MC. In addition, other factors have been suggested, including the use of aspirin and other NSAIDs (non-steroidal anti-inflammatoy drugs like ibuprofen and naproxen), prolonged antibiotic use, infection (Clostridium difficile infection, for example), ingestion of certain foods, and possibly female hormones.

Other autoimmune problems can be associated with MC. Examples include thyroid disease, diabetes type I, rheumatoid arthritis, etc. However, the most common autoimmune problem associated with MC is gluten sensitivity, where the body also begins making antibodies to ingested gluten (a protein found in wheat, rye, oats, and barley). This can prolong and heighten the original colitis until gluten is eliminated from the diet. The type of gluten sensitivity that is associated with MC is usually a milder or earlier stage than that found in classic celiac disease, and as a result, will not show up on the standard tests used to diagnose celiac disease.