Crohn's Disease Overview
Crohn's (also spelled Crohn disease) 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's disease is sometimes called regional enteritis or ileitis. It and a similar condition called ulcerative colitis
are referred to together as inflammatory bowel disease (IBD). 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
- The ulcers may spread and become very large but
are usually separated by areas of relatively healthy tissue with little or
- The mucosal lining of the intestines in Crohn's 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
- 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
as the scar tissue develops.
- 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.
This leads to the formation of fistulas between the bowel and other organs and
structures in the abdomen.
- Crohn's 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
- Crohn's 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's 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.
- Inflammatory bowel disease (Crohn's disease and ulcerative colitis) is one of the five most prevalent GI diseases in the United States. IBD is a chronic medical condition that requires a lifetime of care. IBD is responsible for the disability of approximately 119,000 individuals in the United States.
- Crohn's disease is more prevalent in whites than in
African Americans and Asians.
- In the United States, Europe, and South Africa, Crohn's
disease is 2 to 4 times more common among people of Jewish descent than among other ethnic
or social groups.
- Crohn's disease is slightly more common among men than
- In general, the prevalence is higher in urban areas
than in rural areas. It is also higher in higher socioeconomic classes.
- Crohn's disease can occur at any age, but most people
newly diagnosed with Crohn's disease are aged 15 to 30 years. It is sometimes newly
diagnosed in people aged 60 to 80 years.
Crohn's 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's disease can live a normal life.
Senthil Nachimuthu, MD, BS
Francisco Talavera, PharmD, PhD
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