Crohn Disease Overview
Crohn disease is a chronic (slowly developing, long-term) inflammation of the digestive tract. It can affect any part of the digestive tract from the mouth to the anus but usually involves the terminal part of the small intestine, the beginning of the large intestine (cecum), and the area around the anus. The inflammation causes uncomfortable and bothersome symptoms and may produce serious damage to the digestive tract.
Crohn disease is sometimes called regional enteritis or ileitis. It and a similar condition called ulcerative colitis are referred to together as inflammatory bowel diseases. These illnesses are known for their unpredictable flares and remissions.
The inflammation usually starts in one or more areas of the mucosa that lines the inside of the intestines.
- The disease may invade deeper tissues of the intestinal wall and spread to involve more areas of the bowel.
- Ulcers may form at the sites of the most intense inflammation.
- The ulcers may spread and become very large but are usually separated by areas of relatively healthy tissue with little or no inflammation.
- The mucosal lining of the intestines in Crohn disease is often described as looking like a cobblestone street, with areas of ulceration separated by narrow areas of healthy tissue.
The damage to the intestinal wall caused by the inflammation results in a wide variety of symptoms and complications.
- The inflammation damages the lining of the intestine so that it cannot absorb nutrients, water, and fats from the food you eat. This is called malabsorption, and it can result in malnutrition, dehydration, vitamin and mineral deficiencies, gallstones, and kidney stones.
- As the inflammation invades deeper into the intestinal tissues, the intestinal wall becomes thicker, narrowing the bowel lumen (the space through which food passes). The intestinal lumen may become so narrow that it becomes obstructed, so that food cannot pass through at all. This obstruction is usually intermittent, meaning that it comes and goes, and gets better with medical treatment. Eventually, however, the obstruction can become permanent.
- If the inflammation in one area spreads all the way through the intestinal wall, the inflamed area can stick to other organs and structures in the abdomen.
- Crohn disease can also cause problems around the anus. These may include tiny but painful cracks in the skin known as anal fissures; tunneling sores called fistulas that cause abnormal connections between the bowel and the skin; or an abscess, a pocket of inflamed or dead tissue that is usually very painful.
- Sometimes fistulas can develop between the intestine and other organs and structures it is not normally connected to, such as between different parts of the bowel, the bladder, the vagina, or even the skin on the outside of the body. This is serious because the contents of the intestine can enter into these other sites, causing infection and other problems.
- Crohn disease can cause a variety of related inflammatory conditions outside of the digestive tract. The usual sites are skin, joints, mouth, eyes, liver, and bile ducts.
- Children with Crohn disease may experience delayed development and stunted growth.
In the United States, the incidence (number of new cases) and prevalence (number of people who have the disease) have increased steadily during the last 50 years.
- About 7 of every 100,000 people in this country have Crohn disease. These are among the highest rates in the world. The incidence is about 1-3 per 100,000 in southern Europe, South Africa, and Australia, and is even lower, less than 1 per 100,000, in Asia and South America.
- Crohn disease is more prevalent in whites than in African Americans and Asians.
- In the United States, Europe, and South Africa, Crohn disease is 2-4 times more common among Jewish people than among other ethnic or social groups.
- Crohn disease is slightly more common among men than women.
- In general, the prevalence is higher in urban areas than in rural areas. It is also higher in higher socioeconomic classes.
- Crohn disease can occur at any age, but most people newly diagnosed with Crohn disease are aged 15-30 years. It is sometimes newly diagnosed in people aged 60-80 years.
Crohn disease can be a debilitating illness. However, with medical treatment and other measures used to reduce the discomfort of flares, most people learn to cope with the condition. Almost everyone with Crohn disease can live a normal life.
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Last Editorial Review: 12/14/2005