Disorders of the Large Intestine and Rectum
When partially digested food reaches the large intestine (colon), the nutrients have already been absorbed by the body. The colon is responsible for absorbing water and pushing out waste matter. The colon’s work is made easier if you eat a healthy diet that includes plenty of fiber from fruits, vegetables, and whole grains. This helps the muscles in your colon push the waste along quickly and efficiently and reduces exposure of the intestinal tissues to carcinogens (cancercausing substances) and other potentially harmful substances.
Ulcerative colitis is a type of chronic inflammatory bowel disease. It is similar to Crohn’s disease (Search Post about that for more info), but it affects only the intestinal lining and is almost always restricted to the large intestine. Ulcerative colitis starts at the rectum and spreads upward through the large intestine. The disease causes chronic diarrhea that is usually bloody; as the intestinal lining dies and sloughs off, ulcers form that release mucus, pus, and blood into the colon. Other symptoms include abdominal pain, fatigue, weight loss, loss of appetite, and rectal bleeding. The nonintestinal symptoms that can occur with Crohn’s disease also can occur with ulcerative colitis. People whose ulcerative colitis extends throughout the entire colon are at much greater risk of developing colon cancer than are those whose disease is limited to the rectum and the sigmoid (lower) colon.
Ulcerative colitis develops most frequently between ages 15 and 40. Most people with ulcerative colitis can control their symptoms by making simple dietary changes, such as avoiding raw fruits and vegetables or highly seasoned foods to minimize damage to the sensitive intestinal lining. Treatment for ulcerative colitis is generally the same as it is for Crohn’s disease. Periods of remission (without symptoms) may last weeks, months, or even years. However, in most people, symptoms eventually return. During severe attacks (10 or more bouts of bloody diarrhea per day), a person must be hospitalized to receive intravenous drugs and feeding and to be monitored for perforation of the bowel. For some people, surgical removal of the rectum and all or part of the colon may be necessary.
Irritable Bowel Syndrome
Irritable bowel syndrome is a group of symptoms that includes cramping pain, gas, bloating, and alternating bouts of constipation and diarrhea. Sometimes people with irritable bowel syndrome pass mucus with their bowel movements. Irritable bowel syndrome is also called irritable colon, spastic colon, spastic bowel, mucous colitis, and functional bowel disease. Diagnosis of irritable bowel syndrome is usually made by ruling out other possible causes of the symptoms. Irritable bowel syndrome does not cause permanent damage to the intestines and does not increase the risk of colon cancer.
Stress and diet are the most common triggers for the symptoms of irritable bowel syndrome. Stress probably has a role in irritable bowel syndrome because the nervous system controls the colon and digestion. Contractions of the colon can begin as soon as the person starts eating, and the urge to have a bowel movement may come within 30 to 60 minutes after a meal. High-fat foods (such as red meats and dairy products), caffeine, and alcohol can bring on symptoms. Eating large meals can lead to cramping and diarrhea.
To control irritable bowel syndrome, avoid the foods that cause your symptoms. You also may find relief by eating smaller, more frequent meals and by eating less fat and more fruits, vegetables, and whole grains. Taking fiber supplements also may help. Stress management techniques (search post about that for more info) will help you reduce or control stress. If self-help measures are ineffective, your doctor may prescribe anticholinergic or antispasmodic medication (such as atropine or dicyclomine) to help relieve spasms in the colon.
Diverticula are small bulges or pouches that develop in the colon. These pouches form when the colon strains to move hard stool, and the increased pressure pushes through weak spots in the lining of the colon. This condition may result from eating a diet that is low in fiber. If there are no symptoms or mild symptoms, the condition is called diverticulosis. If the pouches become infected or inflamed—such as when stool or bacteria become trapped inside them—the condition is known as diverticulitis. Diverticular disease occurs mainly in developed countries such as the United States, where people regularly consume low-fiber processed foods.
Diverticulosis usually does not cause symptoms, although some people may experience tenderness or pain in the lower abdomen. Others may have mild cramps, bloating, and alternating bouts of constipation and diarrhea. Eating a well-balanced diet (search post for more info) that is low in fat and high in fiber, taking fiber supplements, and taking antispasmodic medication will relieve the symptoms of diverticulosis and help prevent diverticulitis. If you have no symptoms, you do not need treatment.
The most common symptom of diverticulitis is abdominal pain, especially in the lower left abdomen. The pain may be accompanied by fever, nausea, vomiting, chills, cramping, and constipation. Diverticulitis is usually detected during a diagnostic examination such as a colonoscopy or a gastrointestinal (GI) series (see “Diagnostic Procedures,” Post).
Treatment for diverticulitis includes antibiotics, intravenous fluids, and bed rest. Surgery may be required if an infected diverticulum ruptures and produces an abscess (a pus-filled sac) or causes peritonitis (inflammation of the lining of the abdominal cavity), if a stricture (narrowing) develops in the colon, or if bleeding cannot be controlled. In most cases the affected portion of the colon is removed, and the remaining portions are rejoined. A colostomy also may be required.
Proctitis is inflammation of the lining of the rectum. Symptoms include bleeding, constipation, a feeling of fullness in the rectum, pain in the lower left abdomen or around the anus, and, sometimes, discharge of mucus and pus. Proctitis may occur after certain medical treatments, such as radiation therapy or antibiotic use. Inflammatory bowel disease, sexually transmitted diseases, injury to the rectum, and infection also may cause proctitis.
Diagnosis of proctitis is made by a proctoscopy (see “Diagnostic Procedures,” Post) and a biopsy (removal of a small piece of tissue for microscopic examination). Once the underlying cause of the inflammation has been determined, the doctor will recommend appropriate treatment. If inflammatory bowel disease is the underlying cause, the doctor probably will prescribe corticosteroid medication to relieve the symptoms.
An abscess is an infected cavity filled with pus. Abscesses can occur when bacteria penetrate and become trapped in the tissues of the anus or rectum. Anal abscesses that appear close to the tissue surface are very painful. Abscesses in deeper tissues tend to cause more general symptoms of infection such as fever, malaise (a vague feeling of being ill), and tenderness around the abscess. Your doctor will open and drain the abscess. When an anal abscess is drained, a fistula (an abnormal connecting channel between the intestines and the skin in the genital area) may develop spontaneously. Surgery is required to repair a fistula.
Hemorrhoids are swollen (varicose) veins in the lining of the anus and rectum. Hemorrhoids may result from straining during bowel movements. Other possible causes include heredity, aging, and chronic constipation or diarrhea. In general, hemorrhoids can be irritating and painful but are considered normal and do not threaten your health.
Symptoms of hemorrhoids include persistent itching or discomfort around the anus and pain, especially during bowel movements. Hemorrhoids also can bleed. Be sure to tell your doctor if you see blood in your stool, on toilet paper, or in the toilet; bleeding can be a sign of colorectal cancer (search for colorectal cancer for more info).
A doctor can diagnose hemorrhoids by examining the anus and rectum with a gloved finger. To confirm the diagnosis, the doctor probably will perform a visual examination of the inside of the anus and rectum in a procedure called proctoscopy (search for Diagnostic Procedures for more info). In some cases the doctor may perform a colonoscopy (search for Diagnostic Procedures for more info) to examine the colon to rule out cancer and other possible causes of bleeding.
There are a number of steps you can take to relieve symptoms of hemorrhoids: eat a high-fiber diet that includes plenty of fruits, vegetables, and whole grains; drink at least eight 8-ounce glasses of water every day (but avoid alcohol and caffeine, which can irritate hemorrhoids); soak in a bath of plain warm water once or twice a day and cleanse the affected area with mild soap; apply ice packs to the area (to reduce swelling); and apply an over-the-counter hemorrhoidal cream to the affected area for a limited time (be sure to follow package directions). Outpatient procedures to remove hemorrhoids include rubber band ligation, in which rubber bands are placed around the base of a hemorrhoid to cut off its blood supply, causing it to shrink and fall off, and sclerotherapy, in which a chemical solution is injected directly into a hemorrhoid, causing it to shrink. In another procedure, heat is used to seal a hemorrhoid and stop it from bleeding. Some hemorrhoids must be removed surgically.
The appendix is a small, finger-shaped organ with no known function that projects out from the large intestine. For reasons that are not fully understood, the appendix can become inflamed. Inflammation of the appendix is called appendicitis. Although appendicitis occurs most often in children and young adults, it can occur at any age. Symptoms occur in only about half of all people who have appendicitis, and many of those symptoms occur in other acute abdominal disorders. Because of the high risk of serious and potentially fatal infection associated with appendicitis, you should seek medical help immediately if you experience sudden, severe abdominal pain either with or without any of the following symptoms:
• pain that starts near the navel and moves to the lower right area of the abdomen
• pain that worsens when taking deep breaths, coughing, or sneezing
• pain that worsens when even slight pressure is applied to the area
• nausea or vomiting after the pain begins
• fever after the pain begins
• abdominal swelling
• inability to pass gas
• blood in the stools (they are red-streaked or look black and tarry)
To diagnose appendicitis, a doctor examines your abdomen by gently pressing on it and listening through a stethoscope for sounds of normal digestion. (If you have a severe infection, there are no sounds.) Based on your symptoms and the examination, the doctor will admit you to the hospital for surgery to remove your appendix. He or she may perform a procedure called laparoscopy to confirm the diagnosis. If the appendix has not ruptured, the doctor can remove it through the laparoscope (viewing tube). In other cases, he or she may remove the appendix through a larger incision in the abdomen. Both types of surgery are performed in the hospital using general anesthesia. You will be in the hospital for 1 to 3 days, depending on the severity of your condition.
A polyp is a mushroom-shaped growth of tissue in the
inner lining of the wall of the colon.The most common
type of polyp, called an adenomatous polyp (shown here),
is noncancerous, but it can grow and become cancerous.
A polyp is a growth of tissue in the lining of the wall of the colon. Polyps usually cause no symptoms and often are detected during a routine colonoscopy (search Diagnostic Procedures for more info). Research suggests that a high-fat, low-fiber diet may lead to the development of polyps in the colon. Heredity also may be a factor. A person who develops one polyp is likely to develop more polyps in the future and should be monitored by colonoscopy regularly.
Small, benign (noncancerous) polyps are common in the colon and usually do not cause symptoms or affect your health. However, an adenomatous polyp (the most common type of polyp) is noncancerous but can become cancerous. Therefore your doctor will remove these polyps as soon as they are detected to prevent development of cancer. Small polyps can be removed through a colonoscope, but removal of larger polyps requires general surgery. Left untreated, small polyps will grow. The larger the polyp, the more likely that it is cancerous.
Cancer of the colon and cancer of the rectum are two of the most common forms of cancer. The term “colorectal cancer” is often used to describe them. Colorectal cancer is the third most common type of cancer among men and also is the third leading cause of cancer death among men. But the rate of cure is high—up to 90 percent—when the disease is detected and treated early.
Nearly all cases of colorectal cancer arise from previously benign (noncancerous) adenomatous polyps. The risk of colorectal cancer increases with age (occurring most often after age 50) and may be higher among people who eat a high-fat, low-fiber diet. People with ulcerative colitis (see ulcerative colitis for more info) are more likely to develop colon cancer. Colorectal cancer can run in families: if you have a parent, sibling, or child who was diagnosed with colon cancer, your risk of developing colon cancer is greater than normal.
A doctor can detect cancers just inside the rectum during a digital rectal examination. Doctors recommend an annual digital rectal examination for all men 40 and older. The most common screening test to detect colon cancer is the fecal occult blood test, which checks for traces of blood in samples of stool. Doctors recommend that all men over age 50 have a fecal occult blood test every year.
A more accurate test, recommended every 5 years, is called a flexible sigmoidoscopy, a visual examination of the lower third of the colon and rectum that uses a probe with a light and a camera attached. The doctor inserts the instrument into the colon and looks through the viewing tube to check for polyps or signs of cancer. A colonoscopy is a similar procedure, but it examines the entire length of the colon. The doctor performing a sigmoidoscopy or colonoscopy may remove tissue for a biopsy during the test.
An alternative to these procedures is a barium enema. During this test, contrast medium (a dye) is inserted through the rectum into the colon, and X rays are taken of the colon to look for abnormalities. If a suspicious area is detected in the colon during a barium enema, the doctor will order a biopsy (microscopic examination of a small piece of tissue that has been removed from the colon) to confirm the diagnosis of cancer.
A tumor in the colon is classified by stages, according to whether it has affected only the top layer of the intestinal lining, penetrated farther down into the lining, involved the surrounding lymph nodes (part of the body’s immune system that fights infection), or spread to other parts of the body.
Treatment for colon cancer depends on how far the cancer has advanced and may include surgery, radiation therapy, chemotherapy (treatment with powerful anticancer drugs), or some combination of these. Surgical removal of the tumor and surrounding colon and lymph tissue is the most common treatment for colon cancer. After the cancerous section of the colon has been removed, the healthy sections are reconnected. In some cases the surgeon may perform a colostomy to provide an outlet for feces. If the tumor is large, you may need to undergo radiation therapy before surgery to help shrink the tumor. Radiation therapy also may be used after surgery to ensure that all the cancerous cells have been killed.
If the surgeon is not sure that all the cancer has been removed, or if the cancer has spread to other parts of your body, you will need to undergo chemotherapy or possibly immunotherapy, in which your body’s immune system is stimulated to destroy cancer cells.
Chemotherapy drugs may be given orally or intravenously. Several different types of drugs may be given simultaneously. You may need to be hospitalized during the first few days of treatment and then continue the treatment on your own at home. Chemotherapy usually is administered in cycles. For example, you may take the drugs for several weeks, stop taking the drugs for several weeks, and then repeat this cycle. Your doctor will explain the risks, advantages, and side effects of these therapies. Some people benefit from participating in a support group, which allows them to share information and experiences with others who are in a similar situation. Ask your doctor to recommend a support group in your area.