What is ulcerative colitis?

November 17, 2020


Ulcerative colitis is an intestinal inflammatory disease that starts in the rectum and spreads out to all the sections of the colon (ascending, transverse and descending). It is a chronic disease that results in inflammation in the wall of the large intestine, known as mucosa, which works as a barrier against harmful substances and helps with secreting and carrying nutrients, water and minerals. At times, the inflammation of the mucosa extends to another layer of the colon which causes the wall to get thinner. That contributes to the likelihood of its perforation. Just like in Chron’s disease, ulcerative colitis (UC) presents periods of activity and others of remission.

UC causes the excessive apparition of ulcers, mucus and blood on the inside surface of the intestine. Those ulcers usually happen to be little and superficial. However, if they spread, they generate an accumulation of inflammatory cells. When those wounds heal, they may cause the apparition of little masses of tissue.

Besides, UC may affect other parts of the body like eyes, skin, joints… what is known as extraintestinal manifestations. That makes the patient suffer from joint pain, skin spots, stones in the gallbladder, or eye inflammation.

Just as the cause of the disease is unknown, there is no cure for it either. Nevertheless, if the symptoms are too injurious and the treatments do not work effectively on the patient, surgery may be done. It consists of reconstructing the intestinal transit with a reservoir. Another option is to remove the colon. That is considered to be the cure for the UC. Notwithstanding, it only happens after the failure of every other treatment. It is individually studied in every patient, in cases of extreme necessity.

What is the cause of ulcerative colitis?

UC arises as a consequence of a poor immune response to the organism itself. The origin of this inappropriate response is still unknown, but the stronger theories point at the genetic predisposition, the bacterial flora and the environmental influences as the possible causes of the disease. 

There exist multiple harmful substances to our intestine, to which the immune system (under normal circumstances) responds properly protecting the organism from any damage that may affect it. Sometimes those intestinal immunologic responses fail and that is when the UC appears. This situation is usually prolonged and maintained in the long term, making the ulcerative colitis a chronic disease.

The reasons why those immune responses fail are still unknown, but the most powerful theories state that it could be due to genetic alterations of the intestinal immune system. Its cells have the ability to notice the presence of different pathogenic agents and they are able to stop them. Some people present genetic alterations in those agents’ receptors, which lead to wrong identifications and, consequently, to wrong inflammatory responses.

Is the ulcerative colitis hereditary?

Despite the implication of genetic factors in the apparition of the disease, it is not considered to be hereditary. That is because the external factors like tobacco, the previous gastrointestinal infections, some drugs, or even the stress have influence on it too. It does exist the hereditary influence in suffering from UC. However, it is not more than 15% of the risks for first-degree relatives.

How is ulcerative colitis diagnosed?

Diagnosing the disease is sometimes difficult, because the symptoms may be diverse and, in some occasions, they are attributed to other conditions. The blood and stool tests are the most reliable ones, they can help identify if there is inflammation or infection; the so-called image tests, where the inflamed zones may be seen, besides the extension and the seriousness of the disease. And lastly, the endoscopic tests with biopsies confirm the diagnosis of the UC. Those provide any type of necessary information in order to know if there exist ulcers, inflammation, bleeding or stenosis.

Ulcerative colitis1 is an intestinal inflammatory disease that affects the colonic mucosa (large intestine). This mucosa works as a barrier against harmful substances. It also helps secreting and transporting nutrients, water and minerals; and lubricating the inner part of the intestine in order to facilitate defecation. Its inflammation is produced because the immune system generates an inappropriate inflammatory response against the organism itself. The origin of this failure in the intestinal immune system’s responses is not fully known.

When the mucosa gets inflamed, little wounds (ulcers) appear in the inner lining of the colon. This chronic inflammation starts in the rectum and spreads out to other sections of the colon (ascending, transverse and descending). That means that the affectation may have a variable extension.

The most common symptoms of the ulcerative colitis are liquid defecations with mucus and/or blood, stomach ache, straining to defecate, fever, weight loss and fatigue. Besides, other organs like skin, eyes, bones, etc. may be affected. Most people suffering from ulcerative colitis experience from mild to moderate symptoms. There will be periods of activity when the symptoms occur (called flares). However, there are also periods of normality when the disease seems to disappear (called remission phases). Some people may experience long remission phases.

Risk factors As well as Crohn’s disease, UC is a modern age disorder. In fact, the frequency has increased in developed countries since the mid-twentieth century. This disease affects males and females approximately in equal proportions.
The risk factors may be:

  • Age. Even though it may appear at any age, it generally occurs before the age of 30. Nevertheless, there are also cases in which the disease has been diagnosed after the age of 60.
  • Race or ethnic origin. Although white people have a higher risk of experiencing the disease, any race can have it. If you have Ashkenazi Jewish ancestry, the risk is higher.
  • Family history. It is frequent to find UC cases within the members of the same family. Between 8 and 14% of the patients with ulcerative colitis have a family history of inflammatory bowel disease. Therefore, the risk increases when you have a close relative (parent, sibling or son/daughter) who suffers from this disease.

The cause of the ulcerative colitis and other unknown issues for the science Even though science has made great efforts to find out the cause of ulcerative colitis, it is still unknown. Science still wonders what the specific cause of the inappropriate inflammatory response of the immune system is. According to GETECCU2, current researches state that the disease may appear as a result of a complex interaction of several factors.

One of those factors is a person’s genetic predisposition (susceptibility) to suffer from the disease. However, there are other factors that also seem to be the key in the appearance of the UC like the exposition to environmental factors, the intestinal commensal microflora and the possible involvement of infectious agents. It is believed that the genetic alterations affect the ability of the immune system to tolerate the commensal bacteria and the intensity of the inflammatory response against those bacteria.

Nonetheless, the genetic origin is not completely clear yet. In conjunction with this issue, there exist questions about the pathogenesis of ulcerative colitis that still pose a challenge to science. Why is the inflammation restricted to the mucus layer? Are the epithelial cells of the colon the specific aim of an immune response? How does the luminal microbiota affect the inflammatory response?


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