Crohn's disease is an acute and chronic inflammation of the gastrointestinal tract. Though it can affect any tissue from the mouth through the anus, it commonly involves the small bowel, most frequently the ileum - that portion closest to the large intestine. Crohn's disease is one form of inflammatory bowel disease.
What is going on in the body?
The causes of Crohn's disease are not completely understood. The disease appears to occur because bacteria that normally inhabit the bowel gain entry to the tissues inside the bowel wall and trigger a response from the immune system. Immune cells then begin to attack the cells of the bowel wall itself (an "autoimmune" response), causing the signs and symptoms of inflammation that we recognize as Crohn's disease. About 15 percent of people with Crohn's also have abnormal inflammation in other parts of the body such as the eyes, joints, or skin.
What are the causes and risks of the disease?
The causes of Crohn's disease are not completely understood, but the features of the disease suggest an autoimmune disorder. While further research is needed, the best current theory is that the bacteria in the bowel gain inappropriate entry into the bowel wall, triggering an immune response against the surrounding tissue. It is likely that inherited factors play a role, because 20% to 25% of the people who have Crohn's disease have a close relative with this or a similar disease. Crohn's is seen about equally among men and women, and more often in whites than blacks. The disease most often begins between 15 and 35 years of age but can occur later in life.
What can be done to prevent the disease?
There are no effective ways to prevent Crohn's disease. However, tobacco smoking aggravates the disease and should be discontinued. Non-steroidal anti-inflammatory medications (such as ibuprofen) may make the symptoms of Crohn's worse.
How is the disease diagnosed?
The diagnosis of Crohn's disease begins with a medical history and physical examination. A complete blood count (CBC) may show anemia (a low level of red blood cells). Lab studies may also show abnormal liver function and low levels of certain vitamins and minerals. There is no one test or feature of the disease that confirms the diagnosis.
Endoscopy (the passing of a small lighted telescope through the anus into the bowel to visualize the tissue, take pictures, and snip off tissue samples for lab examination) is very helpful in the evaluation of Crohn's Another common test is the barium enema. In this test, a contrast agent called barium is injected into the intestine and X-rays are taken. CT and MRI scanning are often helpful for diagnosis and followup of Crohn's, especially if the person has abscesses or fistulas. Sometimes the diagnosis is made during surgery that is performed to find the cause of severe abdominal pain.
Long Term Effects
What are the long-term effects of the disease?
The course of Crohn's disease varies. Because it has a tendency to come and go, it may include periods with no symptoms. If the section of bowel most affected is removed surgically, sometimes the disease recurs in another section. A fistula can form either as a direct result of the disease or as a complication of surgery. A fistula is an abnormal passage or duct connecting two different areas of bowel or connecting the bowel to the outer skin, usually near the rectum. Other long-term effects include anal fissures, which are small tears, and pockets of pus near the rectum. A bowel obstruction or a hole or perforation in the intestines is also possible.,About 5% to 10% of Crohn's patients will die from the disease, mostly because of overwhelming bodywide infection that spreads from the diseased bowel through the bloodstream. There is also a slightly increased risk of colorectal cancer in people who have Crohn's disease.
What are the risks to others?
Crohn's disease is not contagious and poses no risk to others. There is some tendency for the disease to run in families.
What are the treatments for the disease?
Medications used to treat Crohn's disease include the following:
- aminosalicylates, such as sulfasalazine and mesalamine (i.e., Asacol)
- corticosteroids, such as prednisone, methylprednisolone, and a newer agent called budesonide (i.e., Entocort EC) that acts locally on the surface of the bowel and is not absorbed as are other steroids
- medications that blunt the body's immune response, such as azathioprine, 6MP, (mercaptopurine, i.e., Purinethol) and methotrexate (i.e., Trexall)
- antibiotics, such as metronidazole (i.e., Flagyl) and ciprofloxacin(i.e., Cipro, Proquin), for infections and fistulas
- inflixamab (i.e., Remicade), a medication that targets the chemicals that frive inflammation
Some persons need extra vitamins, minerals, and salts. A healthy diet is essential for maintaining body weight. Milk products may be restricted if the person also has lactose intolerance. In severe cases, a person may need to be fed through an intravenous tube to improve his or her nutritional status. Fifty to Seventy percent of the people with Crohn's disease will have surgery at least once, however, surgery is not curative and may be required more than once.
Several different surgical approaches have been used:
- A section of the intestines that is severely damaged or obstructed may be removed with a procedure called a resection and anastamosis. The damaged portion is cut out, and the bowel is sewn back together.
- If the rectum is diseased, an ileostomy may be done. This procedure involves taking a portion of the bowel to the outside through a hole in the abdomen and attaching a drainage bag.
- An incision and drainage may be done to drain abscesses, or pus pockets, near the rectum.
- A fistula repair may be done to close abnormal openings caused by the disease.
What are the side effects of the treatments?
Many of the medications used to treat Crohn's disease can cause stomach upset, allergic reactions, and an increased susceptibility to infection or even cancer. Steroids such as prednisone can cause softening of the bones (osteoporosis). Because people with Crohn's disease have increased susceptibility to infections, they should always be kept up to date on their immunizations, and monitored for tuberculosis infection with a skin test.
Persons taking metronidazole may have severe vomiting and abdominal pain if they drink alcohol. Surgery may be complicated by bleeding, infection, or allergic reaction to the anesthetic.
What happens after treatment for the disease?
Crohn's disease is a long-term disease with occasional flare-ups. There can be periods without any symptoms. However, the symptoms usually reappear.
How is the disease monitored?
There is no specific test to monitor Crohn's disease. However, affected persons need to monitor themselves symptoms carefully and report any new or worsening symptoms, especially abdominal pain, fever, or diarrhea, to the healthcare provider. Because persons with Crohn's are at increased risk for colon cancer, they should receive an endoscopy of the colon (colonoscopy) when the diagnosis of Crohn's is made.