Crohn's (or Crohn) disease is a type of chronic bowel inflammation. It usually affects the small intestine and less commonly the colon, but it can involve the entire gastrointestinal tract, including the mouth, esophagus, and stomach. The chronic inflammation that is the basis of Crohn's disease causes ulceration, swelling, and scarring of the parts of the intestine that it involves. It eventually requires surgery for most people. Other names for Crohn's disease include granulomatous enteritis, regional enteritis, ileitis, and granulomatous colitis when it involves the colon.
The cause of the chronic inflammation in Crohn's disease is unknown. The leading theory is that inflammation is initiated by bacteria that reside within the intestine. Whereas most inflammation usually is suppressed, and the disease caused by the inflammation subsides, in Crohn's disease the inflammation is not suppressed, and the inflammation continues. The continuing inflammation probably occurs because of environmental factors (i.e., the bacteria) as well as genetic factors that affect the immune system. Crohn's sometimes runs in families, too. Having a parent or sibling with the disease raises your own risk.
Crohn's disease most commonly affects children in their late teens and young adults in their 20s and 30s. Nevertheless, it can affect infants and young children as well. Crohn's disease is not rare; 100,000 teens and preteens in the U.S. have Crohn's disease. For children, the social problems created by the symptoms of Crohn's disease are difficult to deal with since the disease can restrict activities. The chronic inflammation can also add to the social difficulties with stunted growth and delayed puberty. Emotional and psychological factors always must be considered in young people with Crohn's disease.
The first signs of Crohn's disease are small ulcers, called aphthous ulcers, caused by breaks in the lining of the intestine due to inflammation. The ulcers become larger and deeper. With the expansion of the ulcers comes swelling of the tissue, and finally scarring of the intestine that causes stiffness and narrowing. Ultimately, the narrowing can obstruct the flow of food being digested in the intestines. The deepening ulcers can fully penetrate the intestinal wall and enter nearby structures such as the urinary bladder, vagina, and parts of the intestine. These penetrating tracts of inflammation are called fistulas.
Both Crohn's disease and ulcerative colitis are chronic diseases of intestinal inflammation. Whereas ulcerative colitis only involves the colonic portion of the gastrointestinal tract, Crohn's disease can affect any portion of the gastrointestinal tract from mouth to anus. Whereas the inflammation of ulcerative colitis involves only the superficial lining of the colon, the inflammation of Crohn's disease goes deeper into the intestinal walls and, as previously mentioned, even beyond the walls.
Inflammation in ulcerative colitis is continuous; that is, the inflammation does not skip areas. Thus, the colon is involved from the most proximal margin of the inflammation - be that ascending, transverse or sigmoid colon - all the way to the anus. On the other hand, the inflammation of Crohn's disease can be present in several portions of the intestines with skipped areas without inflammation in between.
The most common symptoms of Crohn's disease are abdominal pain and diarrhea. Other signs of inflammation are often present, including fever and abdominal tenderness. Because symptoms can be worsened by eating, the intake of food is reduced, and this leads to loss of weight, and, less commonly, nutritional deficiencies. Slow, continuous loss of blood into the intestine that may not even be recognizable in the stool can lead to iron deficiency anemia.
Several complications of Crohn's disease have already been mentioned, including nutritional deficiencies, loss of weight, anemia, growth retardation, and delayed puberty. Two more serious complications also mentioned previously are strictures or narrowing of the intestine due to scarring and the formation of fistulas. Massive intestinal bleeding and perforation are unusual.
There are also intestinal manifestations of Crohn's disease that occur outside the intestines, some of which may be debilitating. These include arthritis, inflammation of the eye that can impair vision, skin diseases that vary from mild (erythema nodosum) to severe (pyoderma gangrenosum), gallstones, and loss of bone due to nutritional deficiencies. Most of these complications are believed to be due to inflammation outside of the intestine.
Although Crohn's disease is usually easy to diagnose, the wide variation in severity of symptoms - from mild to severe - and the non-specific nature of the symptoms that mimic other intestinal inflammatory diseases (for example, diverticulitis), sometimes makes arriving at a diagnosis challenging.
- The pattern of the symptoms and a family history of Crohn's disease are very important in diagnosis.
- Often other, more common intestinal inflammatory diseases need to be excluded, for example, intestinal bacterial and parasitic infections.
- Stool may be examined for signs of inflammation such as blood or white blood cells. Fever and an elevated white blood cell count in the blood may suggest inflammation somewhere in the body.
- Ultimately the inflamed bowel must be visualized and, if possible, biopsied. This can be done by barium X-ray studies, particularly a small intestinal barium X-ray, but probably better by colonoscopy with examination of the terminal ileum (which usually is involved in Crohn's disease) that also allows for biopsies.
- When inflammation does not involve the terminal ileum, it may be necessary to do capsule endoscopy (the swallowing of a tiny camera) or enteroscopy (fiberoptic endoscopy of the small intestine) to visualize the entire small intestine. Enteroscopy has the advantage over capsule endoscopy of allowing for biopsy as well as visualization.
Treatment of Crohn's disease is directed at reducing inflammation - treating flares in the activity of the disease, and maintaining remissions. The type of medication that is used depends on the severity of the inflammation and how well the disease responds to initial treatment. If inflammation does not decrease with initial treatment, more powerful medications are used, though risks for serious side effects increase. With severe disease, the more powerful medications may be used immediately.
Surgery is avoided in Crohn's disease if possible because it is likely that inflammation will recur even when it appears that all inflammation has been removed during surgery. There are situations in which surgery often becomes necessary such as with strictures, intestinal obstruction, or symptoms that do not respond to any medical treatment. Usually, the surgery that is done is kept to the minimum that is necessary to take care of the complication. Surgery may include removal of parts of the intestine, stretching of strictures, and removal of fistulas. But at times it may require resection of the entire colon, which may necessitate a colostomy or ileostomy.
The treatment of choice for Crohn's disease is medication to control the inflammation. The primary goal is to relieve symptoms by treating flares and putting the disease into remission. A secondary goal is to postpone or prevent surgery. The choice of medication depends on the severity of the flare, the location of the inflammation, and the presence of complications of the disease.
- Aminosalicylates and antibiotics suppress inflammation and are associated with the fewest side effects.
- Corticosteroids are effective at suppressing inflammation but are associated with serious side effects when used for prolonged periods of time.
- Other medications suppress the immune system in general and can be used for prolonged periods of time.
- Biologics are injectable medications that reduce inflammation by blocking the action of specific chemicals that are released by immune cells that provoke inflammation.
Newer suppressors of inflammation and the immune system are being developed all of the time. Two general immunosuppressants are tacrolimus (Prograf, FK 506) and mycophenolate mofetil (CellCept). Newer biologics also are being developed.
MMaintaining good nutrition with Crohn's disease can be a challenge. Some foods may provoke your symptoms, and others may ease them. But no single meal plan will work for every person with Crohn's. Weight loss as well as specific vitamin and mineral deficiencies (for example, iron deficiency anemia) may occur. Patients whose inflammation is still active do not have much of an appetite, so their intake of food is reduced or the types of foods they eat are restricted. Eating can also make symptoms worse, so people with this disease may eat less. Finally, if a substantial portion of the small intestine is inflamed, the inflamed intestine may not absorb nutrients normally. Good nutrition depends on the control of inflammation, but when that is not achievable, it depends on supplemental vitamins, minerals, and calories.
No specific foods are believed to provoke the symptoms of Crohn's disease. Even so, it is always recommended to eliminate foods that seem to exacerbate symptoms. The most commonly recommended dietary change is to reduce intake of milk and dairy products, but this recommendation is based primarily on the possibility of lactose intolerance, a genetic abnormality of milk sugar digestion that is unrelated to Crohn's disease. If the relationship between milk and symptoms is not clear, it probably is a good idea to do a formal lactose tolerance test to learn for certain whether milk and milk products should be eliminated from the diet. It would be a shame to eliminate milk from the diet unless necessary since milk is an excellent source of nutritious calories, protein, vitamin D, and calcium.
People with Crohn's and other forms of irritable bowel disease (IBD) lack some of the gut microbes found in other people. Some of these microbes include anti-inflammatory bacteria. Probiotics are thought to improve gut health by providing living microorganisms that can help repopulate your insides in health-promoting ways. As with any treatment, it is important to discuss probiotics with your doctor before attempting to increase them in your diet. Some probiotics sources include:
- Probiotic supplements
Glutamine is an amino acid, making it a necessary compound for building protein. In fact, glutamine is the body's most plentiful amino acid. It is currently being studied as a supplement that could improve the absorption of nutrition in your intestines. Glutamine helps maintain the lining of your intestines. Indeed, studies have shown that about 30% of your body's plentiful glutamine supply is used by your intestines. Will eating more glutamine help with Crohn's? The data is limited. One review highlighted two small studies that found glutamine may not be beneficial. However, the reviewers noted that the small size of the studies means they should be interpreted with caution.
The Specific Carbohydrate Diet is one of several diet plans that excludes carbohydrates like fiber, grains, and sugars. Those who follow the SCD are advised to eliminate processed and refined foods, as well as soy, lactose, grains, and table sugar. SCD dieters are told to refrain from eating okra, potatoes, and corn as well. The Crohn's and Colitis Foundation warns that following this diet may leave you low on essential nutrients like calcium and vitamin D, and recommends staying in contact with your healthcare team to avoid nutritional deficiencies. Scientists at the University of North Carolina are currently studying SCD as a potential treatment of Crohn's disease. Although the results of this study are not yet known, smaller studies have shown promise.
Active Crohn's disease provides many stresses, and stress makes the symptoms of many diseases worse, including this one. The best treatment for this stress is successful suppression of inflammation. When inflammation cannot be suppressed, patients may become depressed and angry. This can interfere with relationships with friends and families, and it may be helpful to use support groups to help relieve some of the stresses caused by the disease. It also is important to stay as active as possible, readjusting activities to work around symptoms. Adequate rest is important.
For most patients, Crohn's disease is a chronic illness with flares of disease activity and remissions. Appropriate medications, and occasionally surgery, however, will provide a reasonable quality of life for most patients. If there is progression of the symptoms of Crohn's disease the progression usually is slow. The longer the disease is present the more likely complications become, some of which will require surgery (for example, strictures). In fact, most patients require surgery at some point over the course of their disease. It is important to remember that Crohn's disease usually recurs after surgery even if all visible inflammation is removed.
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- Sleisenger and Fordtran's Gastrointestinal and Liver Disease – Pathophysiology/Diagnosis/Management, 9th Edition