Vol 14 No.1, March 2006 InFocus
Crohn's disease is one of 100 known autoimmune diseases. The disease is also called inflammatory bowel disease (IBD), chronic ileitis, regional enteritis, or granulomatous colitis. As many as one million Americans are affected by IBD. It can develop at any age, but most patients report symptoms before 30 years of age. It is most prevalent in teenagers and young adults in their early 20s although young children and senior citizens can also develop Crohn.
The onset of Crohn's disease may be acute or may develop over a period of years before obvious symptoms occur. Many patients report thinking that they are "just prone to diarrhea." The most common symptoms are frequent bowel movements, diarrhea (up to 20 times a day), abdominal pain (often in the lower right side and following meals), fever, fatigue, weight loss, loss of appetite, anemia (too few red blood cells), and joint pain.
It not uncommon for children with Crohn's to be initially diagnosed with irritable bowel syndrome (IBS) because the two diseases share the symptoms of chronic diarrhea and abdominal pain. Children who are diagnosed with Crohn's disease are faced with unique challenges, and they are often more severely affected than adults. However, the symptoms of Crohn's are the same in both children and adults. Parents should be alert to loss of appetite, weight loss, and slowed growth; and they are urged to watch for signs of anxiety and depression as children with Crohn's react to their illness. Crohn's is a chronic disease that children do not outgrow.
Inflammation and malabsorption of calcium and vitamin D can cause bone disease in children and adolescents with Crohn's. Because inflammation causes food and nutrients to pass from the body quickly without being absorbed, children growth may be slowed. In fact, growth retardation can be the first symptom of Crohn's. Some children may require special diets that are low in sodium, fiber, or lactose. Others may need vitamin and mineral supplements or special high-calorie supplements. Sexual development also may be delayed if the onset of the disease occurs before puberty.
In Crohn's disease, the lower part of the small intestine (ileum) and the large intestine (colon) are most commonly affected. It can, however, affect any part of the gastrointestinal tract, from the mouth to the anus. The lining of the digestive tract becomes inflamed and causes sores called ulcers. As time passes, these ulcers tunnel through the digestive tract into surrounding organs, including the vagina, bladder, or skin. These tunnels, called fistulas, are commonly found around the anus and rectum.
How is Crohn's diagnosed? The diagnosis of Crohn's disease is made by taking a medical history, including a discussion of symptoms, a physical examination, and diagnostic tests. It can be very difficult to diagnosis.
Blood tests and stool samples can reveal systemic inflammation, anemia, vitamin deficiencies, and other problems typical of Crohn's. Other diagnostic tests reveal the inflammation and ulcers in the disease. These tests can include the following: flexible sigmoidoscopy, colonoscopy, upper gastrointestinal (GI) series, upper gastrointestinal endoscopy, barium enema, computed tomography (CT) scan, magnetic resonance image (MRI), video capsule endoscopy (VCE), and abdominal x-ray.
How is Crohn's treated? Treatments for Crohn's vary according to the severity of the patient symptoms and the location of the disease and may include drug therapy, surgery, and/or nutritional therapy.
Treatments often begin with antidiarrhea medications. Electrolytes may also be given to patients who become dehydrated because of diarrhea.
Most patients are treated initially with a class of drugs called aminosalicylates which contain mesalamine, a substance that controls inflammation. Inflammation can be controlled also with corticosteroids, especially in patients with active Crohn's disease. However, corticosteroids generally are taken for only a few weeks or months as they can cause serious side effects, including susceptibility to infection, high blood pressure, and osteoporosis.
Antibiotics are prescribed to treat perianal fistulas and other complications in the anal area. They work by reducing the bacterial overgrowth in the small intestine caused by these fistulas.
Immunosuppressants, or drugs that suppress the immune system, also are prescribed to treat Crohn's. They work by blocking the immune reaction that causes inflammation.
Another form of drug treatment called biologic therapy works to block the activity of a protein called the antitumor necrosis factor (TNF). The overproduction of this protein leads to inflammation. Remicade is the first FDA-approved drug for treating Crohn disease specifically. It is used in treating moderate to severe patients who do not respond to standard therapies and for maintaining remission. Other anti-TNF drugs are currently in phase III drug trials and are not yet available.
Approximately 75-80 percent of Crohn's patients will need surgery at some time during the course of their disease. Although not a cure, surgical resection to remove part of the intestine can relieve symptoms which don't respond to drugs or can relieve blockages, abscesses, perforations, and severe bleeding. After surgery, the disease may return to previously normal areas. For some patients, a colectomy (removal of the entire colon) is necessary.
Nutritional therapy can be helpful. Oral supplements or injections may be necessary for patients who have vitamin deficiencies. Weight loss is controlled with nutritional supplements, and some may need temporary feeding by vein. Foods that irritate the bowel, including spicy and high fiber foods, may have to be avoided.
What causes Crohn's disease? Autoimmunity is generally accepted as the cause of Crohn's disease. In an autoimmune disease, the body immune system, which normally targets and destroys substances foreign to the body, such as viruses, becomes misdirected, attacking the very organs it was meant to protect. Studies suggest that Crohn's disease may result from the immune system abnormal response to normal intestinal bacteria. As with other autoimmune diseases, a combination of genes and the environment are factors in developing the disease.
Crohn's disease tends to cluster in families. The risk of developing the disease is ten times greater in persons with a relative who has the disease than in a family with no history of Crohn disease. Scientists have identified a genetic abnormality that may double the risk of developing Crohn's disease. The gene, NOD2/CARD 15, helps immune cells called macrophages target bacterial invasions. This gene is likely to be only one of several genes that increase susceptibility.
Bacterial infections, especially E. coli, are also thought to trigger an immune response that causes Crohn's. Also suspect are viruses, including the measles virus.
Smoking is also a major risk factor for Crohn's although scientists don't know whether it the nicotine or some other ingredient that triggers the disease. Physicians do ask their patients to quit smoking.
It is thought that significant emotional stress may trigger the disease although recent studies have discounted emotional conditions as a cause.
Note: For references and referrals to other sources of information, readers may contact the AARDA office (586-776-3900 or aarda@aarda.org).
