Crohn’s disease is a chronic inflammatory disease of the digestive system, which evolves by relapses (or crises) and phases of remission. It is mainly characterized by attacks of abdominal pain and diarrhea, which can last several weeks or months. Fatigue, weight loss and even under nutrition can occur if no treatment is undertaken. In some cases, non-digestive symptoms that affect the skin, joints or eyes may be associated with the disease.
In Crohn’s disease, inflammation can affect any part of the digestive tract, from the mouth to the anus. But most often, it settles at the junction of the small intestine and the colon (large intestine) (see diagram).
Crohn’s disease was first described in 1932 by an American surgeon, Dr. Burril B. Crohn. It is similar in many ways to ulcerative colitis, another common inflammatory condition of the intestine. To distinguish them, doctors use different criteria. Ulcerative colitis affects only a defined segment of the rectum and colon. For its part, Crohn’s disease can reach other parts of the digestive tract, from the mouth to the intestines (sometimes leaving healthy areas). Sometimes it is not possible to distinguish these two diseases.Prevalence In Canada, Crohn’s disease affects about 50 people per 100,000 population in industrialized countries, but there is great variability across geographic regions. The most reported place in the world is in Nova Scotia, a Canadian province, where the rate rises to 319 per 100,000 people. In Japan, Romania and South Korea, the rate is less than 25 per 100,00029. The disease can occur at any age, including childhood. It is usually diagnosed in people aged 10 to 3030.
CAUSES of Crohn’s disease
Crohn’s disease is due to persistent inflammation of the walls and deep layers of the digestive tract. This inflammation can lead to thickening of the walls in some places, cracks and sores to others. The causes of inflammation are unknown and likely multiple, involving genetic, autoimmune and environmental factors.
Genetic factors of Crohn’s disease
Although Crohn’s disease is not an entirely genetic disease, some genes may increase the risk of developing it. In recent years, researchers have discovered several susceptibility genes, including the NOD2 / CARD15 gene, which increases the risk of disease by 4 or 5. This gene plays a role in the body’s defense system. However, other factors are necessary for the disease to occur. As in many other diseases, it seems that a genetic predisposition combined with environmental or lifestyle factors triggers the disease.
Like ulcerative colitis, Crohn’s disease has features of autoimmune disease. Researchers believe that inflammation of the digestive tract is linked to an excessive immune response of the body against viruses or bacteria in the gut.
It is noted that the incidence of Crohn’s disease is higher in the industrialized countries and tends to increase since 1950. This suggests that environmental factors, probably related to the Western way of life, could have a significant influence on the appearance of the disease. However, no specific factor has yet been detected. Several tracks are however under study. Exposure to certain antibiotics, particularly the tetracycline class, is a potential risk factor. Smokers are at higher risk of developing the disease. People who are too sedentary are more affected than people who are more active.
It is possible, but there is no absolute proof, that eating too much fat, meat and sugar increases the risk. It has long been thought that stress can trigger crises. However, studies to date seem to refute this hypothesis.
The researchers focus on the possible role of infection by a virus or bacteria (salmonella, campylobacter) in the onset of the disease. In addition to infection by an “outside” microbe, an imbalance of the intestinal flora (that is to say bacteria naturally present in the digestive tract) could also be involved.
In addition, some elements seem to have a protective effect. It is a diet rich in fiber and fruit, contact with cats or farm animals before the age of one, appendectomy, and gastroenteritis or infections respiratories. There is also no association between MMR (measles-rubella-mumps) and Crohn’s disease.
Evolution of the disease
It is a chronic disease that is present throughout life. Most often, Crohn’s disease evolves through periods of remission that can last for several months. About 10% to 20% of people have sustained remission after the first outbreak of the disease. The recurrences (or crises) follow one another in a rather unpredictable way and are of variable intensity. Sometimes the symptoms are so intense (inability to eat, hemorrhage, diarrhea, etc.) that hospitalization becomes necessary.
Complications and possible consequences
Crohn’s disease can lead to a variety of health problems. The severity of symptoms and complications, however, varies greatly from person to person.
An obstruction of the digestive tract. Chronic inflammation may result in thickening of the lining of the digestive tract, which may lead to partial or complete blockage of the digestive tract. This can lead to bloating, constipation, or even vomiting of feces. Emergency hospitalization may be necessary to prevent perforation of the bowel.
- Ulcers in the wall of the digestive tract.
- Wounds around the anus (fistulas, deep fissures or chronic abscesses).
- Hemorrhages of the digestive tract, rare but sometimes serious.
- People with Crohn’s disease in the colon have a slightly increased risk of getting colon cancer, especially after several years of illness, and even if they are in treatment. It is therefore advisable to have early and regular detection of colon cancer.
- Under-nutrition, because during crises, patients tend to eat less because of pain. In addition, the ability to absorb food through the wall of the intestine is compromised, in medical language we speak of malabsorption.
- Stunting and puberty in children and adolescents.
- Iron deficiency anemia, due to bleeding in the digestive tract, which can occur with low noise and be invisible to the naked eye.
- Other health problems, such as arthritis, skin conditions, eye inflammation, mouth ulcers, kidney stones or gallstones.
- Crohn’s disease, when in the “active” phase, increases the risk of spontaneous abortion in pregnant women who have it. It can make the growth of the fetus difficult. It is therefore important that women who wish to become pregnant control their disease very well with the help of treatments and discuss it with their doctor.