What causes Crohn's disease?
The cause of Crohn's disease is unknown. There is now evidence of a genetic link as Crohn's frequently shows up in a family group. In addition, there is evidence that the normal bacteria that grow in the lower gut may, in some manner, act to promote inflammation. The body's immune system, which protects it against many different infections, is known to be a factor. There are still a number of unknowns about the cause of the disease. Fortunately, a great deal is known about the disease and especially its treatment. Some scientists suspect that infection by certain bacteria, such as strains of
mycobacterium, may be the cause of Crohn's disease. To date, however, there has been no convincing evidence that the disease is caused by infection. Crohn's disease is not contagious. Although diet may affect the symptoms in patients with Crohn's disease, it is unlikely that diet is responsible for the disease.
The disease has long been suspected of being due to a Mycobacterium because of the similarity of many features to human tuberculosis and veterinary Johne's Disease. Mycobacterium avium subspecies paratuberculosis (MAP), which causes Johne's disease in cattle, is a primary area of research for many scientists and doctors involved in Crohn's disease. This remains a controversial area of research, although recent studies have lent more credence to the theory, and government agencies in some countries have begun investigations into the possibility.
Nearly all practicing physicians and many researchers are not willing to accept that MAP is a primary cause of Crohn's. Dozens of studies have been done in which evidence of MAP infection could not be found in tissue and blood samples of Crohn's patients. However, other studies have been performed which (with more stringent methodology) showing that MAP was found in up to 90% of the Crohn's patients in the study. Mycobacteria are known to be fastidious, which means they are extremely difficult to grow in culture. Therefore, unless very stringent precautions are taken, cultures for mycobacteria can underestimate the presence of the bacterium.
For this reason, PCR is a more promising technique than culture. Researchers have identified an insertion sequence called IS900 that is unique to the MAP organism, and many studies have been performed using PCR to test for the presence of MAP. However, the problem with PCR is that it will detect dead or near-dead ("non viable") MAP organisms, so often times a combination of PCR and careful culture is needed to prove that MAP is present. Researchers using PCR and careful culture have found that live MAP bacteria are present in significant numbers of Crohn's patients, and other studies using PCR and culture have shown that live MAP bacteria are present in significant pertentages of pasteurized milk in the United States, the United Kingdom, and the Czech Republic.
Activation of the immune system in the intestines appears to be important in IBD. The immune system is composed of immune cells and the proteins that these immune cells produce. Normally, these cells and proteins defend the body against harmful bacteria, viruses, fungi, and other foreign invaders. Activation of the immune system causes inflammation within the tissues where the activation occurs. (Inflammation is an important mechanism of defense used by the immune system.)
Normally, the immune system is activated only when the body is exposed to harmful invaders. In patients with IBD, however, the immune system is abnormally and chronically activated in the absence of any known invader. The continued abnormal activation of the immune system results in chronic inflammation and ulceration. The susceptibility to abnormal activation of the immune system is genetically inherited. Thus, first degree relatives (brothers, sisters, children, and parents) of patients with IBD are more likely to develop these diseases. Recently a gene called NOD2 has been identified as being associated with Crohn's disease. This gene is important in determining how the body responds to some bacterial products. Individuals with mutations in this gene are more susceptible to developing Crohn's disease.
More information on inflammatory bowel diseases (ulcerative colitis, Crohn's disease)
What are the inflammatory bowel diseases? - Inflammatory bowel disease (IBD) is a chronic disorder that causes an inflamed and swollen digestive tract or intestinal wall.
What causes inflammatory bowel diseases? - The cause of inflammatory bowel disease is not known. Chronic inflammation present in the intestines of persons with both forms of IBD damages the bowel.
What are the symptoms of inflammatory bowel diseases? - Symptoms of inflammatory bowel diseases can include chronic diarrhea, abdominal cramps or pain, fever, and blood or mucus in the stool.
How is inflammatory bowel disease diagnosed? - To make a diagnosis of inflammatory bowel disease, a doctor must first exclude other possible causes of inflammation.
What're the treatments for inflammatory bowel disease? - Inflammatory bowel disease is treated with medication, exercise, and sometimes, surgery. Treatments for IBD are directed against the inflammation in the bowel.
What're the medications for inflammatory bowel disease? - Medications for inflammatory bowel disease include sulfasalazine, corticosteroids, immunosuppressives, and nonsteroidal anti-inflammatory drugs (NSAIDs).
What is Crohn's disease? - Crohn's Disease is a chronic illness that causes irritation in the digestive tract. Crohn's disease occurs in the last portion of intestine (ileum).
What types of Crohn's disease are there? - There are five subtypes of Crohn's disease, distinguished by the gastrointestinal area in which the disease occurs.
What causes Crohn's disease? - The cause of Crohn's disease is unknown. There is now evidence of a genetic link as Crohn's frequently shows up in a family group.
What are the symptoms of Crohn's disease? - The symptoms of Crohn's disease include abdominal pain, diarrhea, fever, loss of appetite and weight loss.
What are the complications of Crohn's disease? - Common complications of Crohn's disease include the development of an intestinal obstruction, pus-filled pockets of infection, and abnormal connecting channels.
How is Crohn's disease diagnosed? - The diagnosis of Crohn's disease is suspected in patients with fever, abdominal pain and tenderness, diarrhea with or without bleeding, and anal diseases.
What're the treatments for Crohn's disease? - Treatment for Crohn's disease is mainly symptomatic. Medications are very effective at improving the symptoms of Crohn's disease.
What medications cure Crohn's disease? - Medications for Crohn's disease sulfasalazine, Asacol, Pentasa and Dipentum. Mesalamine is useful both to achieve and maintain remission.
What's the surgery for Crohn's disease treatment? - Surgery to remove part of the intestine can help Crohn's disease but cannot cure it. The most used operation in Crohn disease is removing the diseased part of the intestine.
What Crohn's disease diet is suggested? - Diet may have to be restricted based on symptoms or complications of Crohn's disease. No particular food has ever been implicated in causing Crohn's disease.
Crohn's disease in children - Crohn's disease is most often diagnosed in young adulthood. Children facing Crohn's disease have significant self-image issues to deal with.
Crohn's disease and pregnancy women - Women with Crohn's disease who are considering having children can be comforted to know that the vast majority of such pregnancies will result in normal children.
What is ulcerative colitis? - Ulcerative colitis is an inflammatory disease of the bowel, that usually affects the distal end of the large intestine and rectum.
What types of ulcerative colitis are there? - Doctors categorize ulcerative colitis by the amount of colon involved. Variability of symptoms reflects differences in the extent of disease and the intensity of inflammation.
What causes ulcerative colitis? - The cause of ulcerative colitis is not known, but heredity and an overactive immune response in the intestine may be contributing factors.
What are the symptoms of ulcerative colitis? - The symptoms vary according to the extent of the disease. The most common symptoms of ulcerative colitis are abdominal pain and bloody diarrhea.
What are the complications of ulcerative colitis? - Bleeding, the most common complication of ulcerative colitis, often causes iron deficiency anemia.
How is ulcerative colitis diagnosed? - Diagnosis of ulcerative colitis is suspected based on the symptoms that a patient is experiencing. The most important method of diagnosis is endoscopy.
What are the treatments for ulcerative colitis? - Treatment of ulcerative colitis depends on the location and severity of a patient's disease, the presence of complications.
What ulcerative colitis medications are available? - Medications for ulcerative colitis include 5-ASA Compounds, anticholinergic drugs, steroids, and immunosuppressive drugs.
What surgery treats ulcerative colitis? - Surgery for ulcerative colitis involves removal of the entire colon, regardless of whether all or only a portion of the colon is diseased.
Collagenous colitis and lymphocytic colitis - Collagenous colitis and lymphocytic colitis are chronic diseases in which certain kinds of white blood cells infiltrate the lining of the large intestine.