Definition
Crohn's disease is one of the two inflammatory bowel diseases along with ulcerative colitis, also called hemorrhagic rectocolitis. Crohn's disease is a chronic inflammation of the intestine that usually affects the last part of the small intestine (ileum), the large intestine (colon), or both. However, it can occur anywhere along the digestive tract, from the mouth to the anus. The involvement of the digestive tract is discontinuous with alternating diseased and healthy sections.
Epidemiology
There are various risk factors associated with the development of Crohn's disease. Indeed, this disease is more frequently observed in smokers, people with other family members affected by the disease, and Ashkenazi Jews. However, the disease affects men and women equally. Most people develop the disease before the age of 30, but it can also occur later in some cases.
Etiology
The exact cause of Crohn's disease is unknown. The disease may be related to a malfunction of the immune system leading to an excessive intestinal response to an environmental, dietary, or infectious agent, resulting in inflammation.
Symptoms
The symptoms of the disease occur intermittently. Indeed, people with the disease alternate between periods of remission and periods of relapse when the disease is active. Relapse periods occur throughout life and can vary in intensity and duration. In adults, the main symptoms are abdominal pain (cramps), diarrhea, loss of appetite, weight loss, and fever. In children, abdominal pain and diarrhea may be absent. The main symptoms can be growth delay, joint inflammation, fever, or fatigue caused by anemia.
Diagnosis
The diagnosis of Crohn's disease is based on the presence of the aforementioned symptoms, a colonoscopy, and imaging tests. Additional tests are also performed to detect certain complications.
Colonoscopy
Colonoscopy is an examination performed using a probe equipped with a camera inserted through the anus. It allows examination of the intestines, particularly the colon.
Imaging tests
Imaging tests generally include computed tomography (CT) or magnetic resonance imaging (MRI) of the abdomen. These tests are another way to examine the intestines.
Additional tests
These tests are not diagnostic but can reveal certain complications of the disease. For example, blood tests can detect complications such as anemia or the presence of inflammation. Vitamin and mineral assays help detect nutritional deficiencies.
Nutritional consequences
The nutritional status of individuals with Crohn's disease can be characterized by protein-energy malnutrition and deficiencies in nutrients, vitamins, and minerals.
Protein-energy malnutrition
Causes of protein-energy malnutrition include insufficient dietary intake, malabsorption, increased intestinal losses, increased energy needs, and disease activity. Dietary intake may be inadequate due to anorexia or fear of worsening digestive symptoms. Malabsorption is mainly due to resection and/or inflammation of the intestine and interaction with certain medications used in disease treatment. Increased intestinal losses are mainly due to diarrhea and blood loss. Finally, energy needs are increased by inflammation, fever, or growth in children.
Deficiencies in nutrients, vitamins, and minerals
Deficiencies in nutrients, vitamins, and minerals may include proteins, fat-soluble vitamins (A, D, E, K), vitamin B12, folate, iron, magnesium, zinc, and calcium. Protein deficiencies occur notably due to increased intestinal losses and increased needs from inflammation and surgery. Fat-soluble vitamin deficiencies may be observed in the presence of steatorrhea (oily stools). Vitamin B12 deficiencies can occur following resection of the absorption site in the intestine. Causes of iron deficiencies include malabsorption and blood loss. Magnesium and zinc deficiencies may be due to diarrhea. Finally, calcium and vitamin D deficiencies can occur due to interaction with medical treatment, especially with long-term corticosteroid use.
Protein-energy malnutrition and nutritional deficiencies can lead to various complications, such as weight loss, muscle wasting, anemia, osteoporosis, and growth delay in children.
Medical treatment
To date, there is no curative treatment for Crohn's disease. Current treatment aims to reduce inflammation and improve symptoms. It may include antidiarrheal medications, corticosteroids, immunosuppressants, biologic agents, antibiotics, and sometimes surgical interventions. Indeed, most individuals with Crohn's disease will require surgery. Surgery involves removing the sections of the intestine affected by the disease. This helps reduce symptoms but does not cure the disease, which can recur. Also, quitting smoking is strongly recommended since tobacco use increases the risk of relapse. However, nearly half of patients who have had surgery will require another operation later. With appropriate treatment, most people can lead productive lives, but the disease is disabling in about 10% of cases.
Nutritional approach
The goal of the nutritional approach is to reduce symptoms, promote optimal nutritional status, support clinical remission, prevent or delay symptoms, and prevent or correct growth delay in children.
The nutritional approach varies according to the phases of the disease. When the disease is in remission, the goal is to help the patient have a normal and balanced diet according to their tolerance. There is no special diet for Crohn's disease. Sometimes supplements may be necessary, such as iron supplements for patients with chronic anemia. When the disease is in relapse and thus active, a fiber-restricted diet may be recommended. Nutritional treatment may also include the use of enteral nutrition (feeding via a tube administered directly into the stomach) to improve and maintain nutritional status. Finally, parenteral nutrition (feeding administered intravenously) is rare but may be necessary in very severe cases of the disease.
Complications
Crohn's disease includes various complications. One complication is chronic malabsorption, which can lead to the development of osteoporosis, especially in the presence of vitamin D and calcium deficiencies. Another complication is an increased risk of cancer in the sections of the intestine affected by the disease.
Future treatments
Current treatments for Crohn's disease primarily aim to control symptoms. With the emergence of personalized medicine in the treatment of Crohn's disease, therapies are also focusing on preventing disability. Personalized medicine can be defined as the use of treatments tailored to the genetic, clinical, and environmental information of each individual. Thanks to this medicine, models predicting the likely course of the disease are under development. There are also various potential therapies currently under study, including several orally administered molecules. Finally, modifying the microbiota through diet or other means could be beneficial and is also under investigation.
References
- Bouthillier, Lise. January 2019. "Digestive Tract Diseases." NUT 2047 – Clinical Nutrition 2. Montreal: University of Montreal.
- Flynn, S., & Eisenstein, S. (2019). Inflammatory Bowel Disease Presentation and Diagnosis. The Surgical clinics of North America, 99(6), 1051–1062. https://doi.org/10.1016/j.suc.2019.08.001
- Nahikian, M. (2016). Inflammatory Bowel Disease. Nutrition Therapy and Pathophysiology, Cengage Learning, pp. 418–422.
- Roda, G., Chien Ng, S., Kotze, P. G., Argollo, M., Panaccione, R., Spinelli, A., Kaser, A., Peyrin-Biroulet, L., & Danese, S. (2020). Crohn's disease. Nature reviews. Disease primers, 6(1), 22. https://doi.org/10.1038/s41572-020-0156-2
- https://crohnetcolite.ca/A-propos-de-ces-maladies
- https://www.merckmanuals.com/fr-ca/professional/troubles-gastro-intestinaux/maladie-intestinale-inflammatoire/maladie-de-crohn
- https://www.merckmanuals.com/fr-ca/accueil/troubles-digestifs/maladies-inflammatoires-chroniques-de-l-intestin-mici/maladie-de-crohn
- https://www.merckmanuals.com/fr-ca/accueil/les-faits-en-bref-troubles-digestifs/maladies-inflammatoires-chroniques-de-l-intestin-mici/maladie-de-crohn