Digestion & Digestive Health - Crohn's Disease

Causes, Symptoms, Diagnosis & Treatment of Crohn’s Disease

Crohn's disease (regional enteritis, granulomatous ileitis, ileocolitis) is an ongoing disorder that causes inflammation of the digestive tract, also referred to as the gastrointestinal (GI) tract. Crohn’s disease can affect any area of the GI tract, from the mouth to the anus, but it most commonly affects the lower part of the small intestine, called the ileum. The swelling extends deep into the lining of the affected organ. , esophagus, stomach, small intestines, large intestines, and anus but it most commonly affects the lower part of the small intestine, called the ileum. . Sometimes, only the rectum is affected. In both inflammation may stick around for many years, flaring up over and over again.Crohn’s disease is an ongoing disorder that causes inflammation of the digestive tract, also referred to as the gastrointestinal (GI) tract.


Although the exact cause is unknown, an improperly functioning immune system may result in Crohn's disease.
Typical symptoms include chronic diarrhea (which sometimes is bloody), crampy abdominal pain, fever, loss of appetite, and weight loss. The diagnosis is based on an examination of the large intestine with a flexible viewing tube (colonoscopy) and barium x-rays. There is no cure for Crohn's disease.
Treatment is aimed at relieving symptoms and reducing inflammation, but some people require surgery.

The cause of Crohn's disease is not known for certain, but many researchers believe that a dysfunction of the immune system results in the intestine overreacting to an environmental, dietary, or infectious agent. Certain people may have a hereditary predisposition to this immune system dysfunction. Cigarette smoking seems to contribute to both the development and the periodic flare-ups (bouts or attacks) of Crohn's disease.

In the past few decades, Crohn's disease has become more common worldwide. However, it is most common among populations living in northern climates in developed areas of the world. It occurs about equally in both sexes, often runs in families, and appears to be more common among Ashkenazi Jews. Most people develop Crohn's disease before age 35, usually between the ages of 15 and 25.

Most commonly, Crohn's disease occurs in the last portion of the small intestine (ileum) and in the large intestine, but it can occur in any part of the digestive tract, from the mouth to the anus and even in the skin around the anus. Crohn's disease affects the small intestine alone (35% of people), the large intestine alone (20% of people), or both the last portion of the small intestine and the large intestine (45% of people). The disease may affect some segments of the intestinal tract while leaving normal segments (skip areas) between the affected areas. Where Crohn's disease is active, the full thickness of the bowel is usually involved.


The most common early symptoms of Crohn's disease are chronic diarrhea (which sometimes is bloody), crampy abdominal pain, fever, loss of appetite, and weight loss. Symptoms may continue for days or weeks and may resolve without treatment. Complete and permanent recovery after a single attack is extremely rare. Crohn's disease almost always flares up at irregular intervals throughout a person's life. Flare-ups can be mild or severe, brief or prolonged. Severe flare-ups can lead to intense pain, dehydration, and blood loss. Why the symptoms come and go and what triggers new flare-ups or determines their severity is not known. Recurrent inflammation tends to appear in the same area of the intestine, but it may spread to adjacent areas after a diseased segment has been removed surgically.

Common complications of inflammation include scarring that can produce intestinal blockage (obstruction) and deep ulcers penetrating through the bowel wall that can create pus-filled pockets of infection (abscesses) or abnormal connecting channels between the intestine and other organs (fistulas). Fistulas may connect two different parts of the intestine. Fistulas also may connect the intestine and bladder or the intestine and the skin surface, especially around the anus. Although fistulas from the small intestine are common, wide-open holes (perforations) are rare.

When the large intestine is affected extensively by Crohn's disease, rectal bleeding commonly occurs. After many years, the risk of colon cancer (cancer of the large intestine) is greatly increased. About one third of people who develop Crohn's disease have problems around the anus, especially fistulas and cracks (fissures) in the lining of the mucus membrane of the anus. Crohn's disease may lead to complications in other parts of the body. These complications include gallstones, inadequate absorption of nutrients, urinary tract infections, kidney stones, and deposits of the protein amyloid in several organs (amyloidosis).

When Crohn's disease causes a flare-up of gastrointestinal symptoms, the person may also experience inflammation of the joints (arthritis), inflammation of the whites of the eyes (episcleritis), mouth sores (aphthous stomatitis), inflamed skin nodules on the arms and legs (erythema nodosum), and blue-red skin sores containing pus (pyoderma gangrenosum). Even when Crohn's disease is not causing a flare-up of gastrointestinal symptoms, the person still may experience pyoderma gangrenosum, while inflammation of the spine (ankylosing spondylitis), inflammation of the pelvic joints (sacroiliitis), inflammation inside the eye (uveitis), or inflammation of the bile ducts (primary sclerosing cholangitis) are liable to occur entirely without relation to the clinical activity of the bowel disease.

In children, gastrointestinal symptoms such as abdominal pain and diarrhea often are not the main symptoms and may not appear at all. Instead, the main symptoms may be slow growth, joint inflammation, fever, or weakness and fatigue resulting from anemia.


A doctor may suspect Crohn's disease in a person with recurring crampy abdominal pain and diarrhea, particularly if the person has a family history of Crohn's disease or a history of problems around the anus. Other clues to the diagnosis may include inflammation in the joints, eyes, or skin. The doctor may feel a lump or fullness in the lower part of the abdomen, most often on the right side.

No laboratory test specifically identifies Crohn's disease, but blood tests may show anemia, abnormally high numbers of white blood cells, low levels of the protein albumin, and other indications of inflammation such as an elevated level of C-reactive protein (CRP).

A colonoscopy (an examination of the large intestine with a flexible viewing tube) and a biopsy (removal of a tissue specimen for microscopic examination) are usually the first tests performed after a physical examination and blood tests have been completed.

If Crohn's disease is limited to the small intestine, a colonoscopy will not detect the disease unless the colonoscope is advanced all the way through the colon into the last part of the small intestine where the inflammation most often resides. However, Crohn's disease can almost always be detected on x-rays after barium is swallowed. X-rays taken after barium is given by enema can reveal the characteristic appearance of Crohn's disease in the large intestine. Computed tomography (CT) can show changes that are helpful in distinguishing between Crohn's disease and ulcerative colitis and is the best way to identify complications that occur outside the walls of the intestinal tract, such as abscesses or fistulas. Another way in which the small intestine can be evaluated is with wireless capsule endoscopy (see Symptoms and Diagnosis of Digestive Disorders: Endoscopy).

Treatment of Crohn's Disease

Although Crohn's disease has no known cure, many treatments help reduce inflammation and relieve symptoms.

Antidiarrheal Drugs: These drugs, which may relieve cramps and diarrhea (see Symptoms and Diagnosis of Digestive Disorders

If the disease becomes severe, the person is hospitalized and corticosteroids are given intravenously. Initially, the person is given nothing by mouth, and intravenous fluids are given to restore and maintain body fluids (hydration). People with heavy rectal bleeding may require blood transfusions. People who have more chronic anemia may require iron supplements by mouth or intravenously.

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