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Crohn’s disease is a type of inflammatory bowel disease that can affect any parts of the gastrointestinal tract. Variable manifestations of this condition and the fact that it is not very common complicate the diagnostics of this disease. Even when properly diagnosed and managed, the disease is associated with higher risk of bowel cancer and slightly reduced life expectancy.
Crohn’s disease is considered as a particular type of immune system disorder. In these disorders, body’s immune system attacks its own normal tissues resulting in various condition-specific problems.
This process is probably directed by the presence of certain bacteria. It was reported that certain types of E. coli are more common in people diagnosed with Crohn’s disease. The condition is often viewed as a type of immunodeficiency since the immune system of affected individuals is usually weakened.
The disease causes small ulcerations on the surface of intestine, which become larger and deeper as disease progresses. Deep ulcers can make holes in the wall of intestine leading to formations of fistulas. Formation of fistulas can cause abdominal abscess, fever and pain.
Crohn’s disease is relatively rare and affects approximately 3.2 persons per 1000 in the US and Europe. The disease is more common in industrialized countries. It appears that this rate is growing in recent decades, particularly in the developing countries.
Possible causes of Crohn’s disease
There is a strong underlying genetic component in the development of Crohn’s disease.
It is believed that roughly about half of the risk of developing Crohn’s disease comes from these genetic factors. For instance, gene NOD2 determines how body responds to certain products of bacterial metabolism. People with mutations in these gene may respond to the presence of some bacteria in such a way that their immune system become chronically over-activated and attacks not only bacteria but also normal tissue of gastrointestinal tract where those bacteria can be found.
In addition to the genetic predisposition, environmental, bacterial and immune factors may contribute to the disease development and progression. Smokers are twice more likely to be affected by this condition. Generally weak immune system of an individual may allow excessive growth of various microorganisms in mucosal layer of the gastrointestinal tract. One interesting theory suggests that the excessive hygiene typical for modern society does not allow the immune system to develop to the full strength due to the lack of extental stimuli in the form of various potentially dangerous microorganisms and parasites. The theory partially explains higher prevalence of Crohn’s disease in the developed countries with high standards of hygiene.
It appears that increased consumption of meat increases the chances of developing this condition, while vegetable-based diets reduce these chances. Stress is also thought to play role in the disease development, although the evidences to support this point of view are limited.