Unknown: Ulcerative Colitis
Unknown: Ulcerative Colitis
Ulcerative colitis, or UC, is a form of inflammatory bowel disease or IBD. Unlike Crohn disease, which is another form of IBD, ulcerative colitis affects only the large bowel or colon. It does not affect the small intestine or other parts of the digestive tract. Ulcerative colitis that is limited to the rectum (the lowermost portion of the colon) is sometimes called proctitis. Ulcerative colitis that affects the entire colon, from the rectum to the point where the colon joins the small intestine, is called pancolitis.
It is important to distinguish IBD from irritable bowel syndrome, or IBS. IBS does not involve inflammation of the bowel and is a less serious disease than IBD.
Ulcerative colitis is a disorder of the digestive tract that usually begins slowly rather than suddenly. In response to inflammation of the tissues lining the colon, small sores or ulcers form on the surface of these tissues and produce pus and bloody mucus that the body then expels. The patient typically experiences cramps in the lower abdomen and blood-or mucus-streaked diarrhea several times a day. In the early stages of the disease the patient notices that the stools gradually become looser. As the
disease progresses, the patient may have more frequent stools and a more urgent need to defecate.
Ulcerative colitis does not affect all patients with equal severity. About half of patients with UC have only mild diarrhea (fewer than four stools per day) and cramping whereas the other half may have six or more stools per day with fever, anemia, and complications that affect the eyes or other organs. In addition, the symptoms of ulcerative colitis often come and go; periods of few or no symptoms are called remissions.
A potentially life-threatening but rare form of ulcerative colitis is known as fulminant colitis. In fulminant colitis, the patient has ten or more bowel movements per day, involvement of the entire colon, and the potential for rupture of the colon.
Ulcerative colitis differs from Crohn disease in two important respects: first, the affected portion of the bowel is continuous; there is no pattern of alternation between diseased portions of the bowel and normal portions. Second, unlike Crohn disease, ulcerative colitis is usually limited to the innermost layer of tissue lining the colon, whereas Crohn disease can penetrate to deeper layers of intestinal tissue.
Ulcerative colitis affects between 500,000 and 700,000 people in the United States, with another 500,000 suffering from Crohn disease. Ulcerative colitis is almost entirely a disorder of older adolescents or adults, with two peak age groups: people between fifteen and thirty years of age, and people between fifty and seventy. It can, however, occur in other age groups.
In the developing world, UC primarily affects the upper classes. It is less common in Asia and Africa than in Europe and North America. In the United States, it is more common among Caucasian Jews of Eastern European ancestry than among other racial and ethnic groups, and more common in the northern states than in other parts of the country. Ulcerative colitis is slightly more common among women than men; there are three females for every two males affected.
Having a family member with ulcerative colitis increases a person's risk of developing the disease, but only slightly. An identical twin of a patient diagnosed with UC has a 10 percent chance of developing it.
The causes of ulcerative colitis are not completely understood. The most widely accepted theory holds that the disease is caused by the patient's immune system mistaking bacteria that normally live in the intestine as foreign substances that must be attacked. When the immune system overreacts, white blood cells move in large numbers to the intestines, where they accumulate and eventually cause swelling and destruction of tissue.
Another theory holds that ulcerative colitis is an inherited bowel disorder. There are certain regions of the human genome on chromosomes 1, 3, 5, 6, 12, 14, 16, and 19 that have been linked to UC; however, no single gene from any of these regions has been shown to be consistently associated with ulcerative colitis. Researchers think that a combination of several genes is necessary to trigger the disorder.
At one time it was thought that diet or emotional stress played a role in the development of UC, but these theories are no longer accepted by most doctors. In contrast to Crohn disease, smoking does not increase a person's likelihood of developing ulcerative colitis.
The most common symptoms of ulcerative colitis are bloody or mucus-streaked diarrhea, abdominal cramps, rectal bleeding, and fever or unintended weight loss. Some patients also experience a feeling of fullness in the rectum even when it is empty; night sweats; nausea or vomiting; fatigue; and loss of appetite.
It is not known why some patients with UC have symptoms in other organs or parts of the body, although researchers think that these complications are the result of inflammation triggered by the patient's immune system. Complications outside the digestive tract may include:
- Inflammation of the iris of the eye
- Pains in the joints
- Mouth ulcers
- Liver disease
- Skin rashes
The diagnosis of ulcerative colitis can be complicated because of the need to rule out Crohn disease, irritable bowel syndrome, and intestinal infections. Most primary care doctors will refer the patient to a gastroenterologist, who is a doctor who specializes in diagnosing and treating disorders of the stomach and intestines.
The gastroenterologist will take a history of the patient's symptoms and order one or more of the following tests:
- Blood tests. These may be ordered to check for anemia or signs of infection. A high white blood cell count typically indicates infection somewhere in the patient's body.
- Stool sample. This test can be done to rule out intestinal parasites or bacteria or viruses that may be causing bloody stools.
- Sigmoidoscopy or colonoscopy. A sigmoidoscope is a flexible lighted tube that can be inserted into the rectum and used to examine the last two feet of the colon. A colonoscope is a long flexible tube attached to a video camera and monitor that allows the doctor to examine the entire length of the patient's colon and rectum. The patient must take a laxative the night before a colonoscopy to cleanse the bowel and may be given a sedative in the doctor'soffice to make them more comfortable. The doctor will remove a small sample of tissue for biopsy; this is done to rule out Crohn disease.
- Barium enema. A barium enema is an enema that contains a chalky substance that coats the lining of the rectum and upper colon. X-ray photographs are then taken as the patient lies on a table.
- Computed tomography (CT) scan. The CT scan is an imaging tool to view internal organs.
There is no cure for ulcerative colitis. Treatment of the disease depends on the severity of the patient's symptoms and the amount of the bowel that is involved. Some patients do well with one or more drugs given to reduce inflammation and encourage remission. There are three groups of drugs commonly prescribed for ulcerative colitis:
- Aminosalicylates. These include drugs like sulfasalazine and mesalamine. They can be taken by mouth or as rectal suppositories, depending on the location of the inflammation.
- Corticosteroids. These include prednisone and hydrocortisone. Steroid medications are effective in reducing inflammation but are usually given only for short periods of time because they have potentially serious side effects.
- Azathioprine and mercaptopurine. These are drugs that work to lower inflammation by suppressing the patient's immune system.
Patients who are having a severe attack of ulcerative colitis may need to be hospitalized for treatment of dehydration and blood loss. They may need a special diet for a few weeks or intensive treatment with steroid medications to bring down the inflammation.
Patients at risk of fulminant colitis or who do not respond to medications can be treated with surgery to remove the inflamed portion of the colon. The surgeon can remove the entire colon and rectum and create an artificial opening to the outside of the abdomen called a stoma. The patient's digestive wastes are passed into an ostomy bag attached to the stoma with adhesive. A newer surgical technique involves the creation of a pouch inside the abdomen by joining the lower end of the small intestine to the inside of the rectum and the anus. The patient may still have watery or loose bowel movements but will not need to wear an ostomy bag.
In general, patients with proctitis have a milder course of the disease than those whose colitis affects a larger portion of the colon; they are also more likely to have long periods of remission. Between 25 and 40 percent of patients eventually need surgery for the disease. Ulcerative colitis does not, however, appear to shorten a person's life span.
Patients with ulcerative colitis have an increased risk of colorectal cancer except for those with proctitis only. About 5 percent of patients will eventually develop colon cancer. The risk increases after 10 years of the disease, particularly if the entire colon is involved. Most doctors recommend having a colonoscopy eight years after diagnosis of UC and every one to two years after that to check for signs of colorectal cancer.
There is no known way to prevent ulcerative colitis, because the causes of the disorder are not yet known.
Ulcerative colitis is not likely to become more common in the general American population. Current research is focused on learning more about the role of the immune system in triggering the disease and the effectiveness of newer drugs in treating symptoms.
SEE ALSO Colorectal cancer; Crohn disease; Irritable bowel syndrome
WORDS TO KNOW
Fulminant: Referring to any disease or condition that strikes rapidly and is severe to the point of being life-threatening.
Gastroenterologist: A doctor who specializes in diagnosing and treating diseases of the digestive system.
Pancolitis: Ulcerative colitis that affects the entire colon.
Proctitis: The medical term for ulcerative colitis limited to the rectum.
Rectum: The lowermost portion of the large intestine, about 6 inches (15.2 centimeters) long in adults.
Remission: A period in the course of a disease when symptoms disappear for a time.
Stoma: An opening made in the abdomen following surgery for digestive disorders that allows wastes to pass from the body.
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