Home > Health Topics > Ulcerative Colitis
 Definition | Causes | Symptoms | Diagnosis | Treatment | Prevention References
Ulcerative Colitis : Causes
Western Medicine Chinese Medicine

Ulcerative colitis primarily affects young adults, but it can occur at any age from five to eighty years and women tend to be more commonly affected than men. It is a worldwide disorder with high-incidence areas that include United Kingdom, the United States, northern Europe and Australia. Low-incidence areas include Asia, Japan, and South America.

The causes of ulcerative colitis remain unknown. The major theories include infection, allergy to food component, genetics, environmental factors, and immune response to bacteria or other antigens.

Infection : Although use of antibiotics has been shown to improve treatment of active ulcerative colitis, no specific bacteria or virus have been isolated despite many attempts; therefore ulcerative colitis is unlikely to be due to a simple infection. Organisms such as shigella and pathogenic E. Coli have been investigated as possible infectious agents but they have not been associated with the etiology of the disease.

Food Allergy : The majority of patients with ulcerative colitis are found to be sensitive to milk and this led to claims that food allerg ies , particularly to milk, were the cause of the disease. Although some studies suggest that about twenty percent of patients with ulcerative colitis can benefit from a milk-free diet, there is very little scientific evidence to prove dietary allergy as the etiology of ulcerative colitis.

Environmental Factors : Other environmental factors proposed as contributing factors in the etiology of ulcerative colitis are oral contraceptives and smoking. The use of birth control pills was found to be more common in women with ulcerative colitis compared to women without the disease. Many studies have shown that ulcerative colitis is more common in nonsmokers than in smokers. The risk of developing ulcerative colitis is shown to be highest for previously heavy smokers, especially within the first two years of cessation. Smoking has shown to alter the function of the cells in the inner lining of the colon but the exact mechanism of the protective effect of smoking is unknown.

Genetics : There is some evidence that support the theory that ulcerative colitis may be due to genetic factors. The relatives of patients with ulcerative colitis are more likely to have the same disease compared to the general population and approximately ten to twenty percent of patients affected also have at least one other family member with the same disease. Numerous genes with a possible association with ulcerative colitis have been identified. Possible mechanisms proposed for genetic factors contributing to the cause of ulcerative colitis include metabolic defects and connective tissue disorders.

Autoimmune Disease : The current leading theory suggests that ulcerative colitis is an autoimmune disease, where the body's own immune system triggers an inflammatory response against an antigen in the intestinal wall. In this theory, the patient's immune system mounts an immune response against an antigen, either food particles or microbial organisms which the immune cells recognize as foreign objects, and this immune response triggers inflammatory effects. However, because of similarities between proteins on the cells of the inner lining of the colon and the antigens (dietary or microbial), the patient's own immune system is activated against the cells on the surface of the colon. Once the immune cells are activated, inflammatory mediators are released which not only cause tissue damage but also amplify the immune response and promote further inflammation in the inner lining of the colon.

Ulcerative colitis is a systemic disease that affects many parts of the body, although patients mainly manifest with intestinal symptoms. In TCM understanding, the problem is closely associated with organ dysfunction, in particular the spleen, that cause a failure to self regulate the intestinal environment. TCM specialists generally agree that constitutional weakness, invasion of exogenous pathogens, an unbalanced diet and emotional factors all contribute to the development of the problem. The pathogenesis is described below:

Damp-heat in the large intestine
In TCM theory, the large intestine is a hollow organ belonging to the digestive system; it receives the "impure" parts of digested food from the small intestine and continues to absorb water from these materials. At the end of the process, stools are formed and excreted through the anus. Digestive problems, whether resulting from either external or internal origin, tend to retain dampness in the intestines, and will further transform into damp-heat in the long run. When the damp-heat pathogens disturb the transmission process in the large intestine, diarrhea will occur; and if the intestinal membrane is irritated, the passing stools will have pus and blood.

Liver overacting spleen
In TCM, the liver promotes flowing and spreading movements, which is embodied in three functional aspects: regulating qi, regulating emotions and enhancing the digestive processes. Long-term emotional stimulation cause a state called "liver stagnation", not only making the blood and qi flows sluggish, but also interfering with the digestive functions in the spleen and stomach. This facilitates damp-heat to accumulate in the large intestine.

Spleen and kidney deficiencies
The spleen rules transformation and transportation, which means it is the primary organ in regulating digestion. On the other hand, the kidneys' warming and propelling activities enable the spleen to work properly. Deficiencies in these two organs lead to a chronic state, which causes intestinal problems such as persistent or intermittent diarrhea to occur.

Blood stasis and qi congestion
Long duration of diarrhea leads to a depletion of blood and qi, which cause pathological wastes to form inside the intestines. They can in turn act directly or indirectly on the organs, and give rise to more complex conditions.

Click to see illustration of UC development from a TCM perspective.