Absorption of nutrients in the small intestine can be impaired by bacteria, viruses, parasites, and other microorganisms in food or ﬂuids (including water). Symptoms of food poisoning usually come on sud- denly and include vomiting, diarrhea, cramps, bloat- ing, weakness, and loss of appetite. Symptoms also can occur 12 to 48 hours after consuming contami- nated food or fluid, when the infectious micro- organisms have multiplied to toxic levels in the digestive tract.
Treatment for food poisoning depends on the microorganism that is causing the problem. In most cases all that is needed is bed rest and plenty of clear ﬂuids (such as water, a glucose-electrolyte solution, bouillon, or a sports drink). However, if you have diarrhea that contains blood or mucus or that lasts more than 3 days and a fever that lasts more than
2 days, see your doctor as soon as possible. Also, symptoms of dehydration—excessive thirst, infre- quent urination, dry skin, fatigue, rapid heart rate, dizziness—require immediate medical treatment.
Crohn’s disease is a type of chronic inﬂammatory bowel disease that can occur anywhere in the gastrointestinal tract, although it most commonly occurs in the ileum. Crohn’s disease causes inﬂammation that extends deep into the intestinal walls, causing pain in the lower right abdominal area (where the small intestine and the large intestine meet) and chronic diarrhea. There may be blood, mucus, or pus in the stool. Symptoms also may include rectal bleeding, weight loss, and fever. In some people with Crohn’s disease, abnormal connecting channels called ﬁstulas develop between the intestines and the skin in the genital area. If this happens, intestinal contents may leak through the skin. For reasons that are not known, symptoms also can occur in areas outside the gastrointestinal tract. For example, inﬂammation and redness may occur in the irises of the eyes, and inﬂammation and swelling may occur in the joints. An abnormal immune response may be the cause of these symptoms. Crohn’s disease increases the risk of cancer and makes it more difﬁcult to screen for cancer due to disease-related tissue changes. The cause of Crohn’s disease is unknown, although it appears to run in families.
A doctor can conﬁrm a diagnosis of Crohn’s disease by examining the ileum and the colon with an endoscope (viewing tube) in a procedure called colon- oscopy (see “Diagnostic Procedures,” page 282). There is no cure for Crohn’s disease. Medications such as cortisone and sulfasalazine are used to control the inﬂammation. Drugs also may be used to treat ﬁstulas and the body’s abnormal immune response. Your doctor may recommend that you avoid drinking milk or alcohol or eating spicy or high-ﬁber foods to help prevent worsening of your symptoms. If you are losing weight because your body is not absorbing enough nutrients, your doctor may recommend that you drink a high-calorie liquid nutri- tional supplement every day. This type of nutritional supplement is available in single-serving cans. In severe cases of weight loss, diarrhea, or bleeding, the doctor may recommend intravenous (directly into a vein) feeding in the hospital until the tissue has recovered sufﬁciently to permit normal absorption of nutri- ents. If treatment with medication is ineffective, surgery may be performed to repair a ﬁstula or to remove severely damaged sections of the intestine. Surgery also may be required if the doctor ﬁnds precancerous changes in the cells in the intestine. However, surgery will not cure the disease or prevent recurrence of symptoms.
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 (cancer- causing substances) and other potentially harmful substances.
Ulcerative colitis is a type of chronic inﬂammatory bowel disease. It is similar to Crohn’s disease (see previous page), but it affects only the intestinal lining and is almost always restricted to the large intestine. Ulcerative colitis starts at the rec- tum 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 bleed- ing. 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 peo- ple 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 coli- tis is generally the same as it is for Crohn’s disease. Periods of remission (with- out 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, sur- gical 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 move- ment 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 symp- toms. You also may ﬁnd relief by eating smaller, more frequent meals and by eat- ing less fat and more fruits, vegetables, and whole grains. Taking ﬁber supplements also may help. Stress management techniques (see page 118) will help you reduce or control stress. If self-help measures are ineffective, your doc- tor 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 symp- toms, the condition is called diverticulosis. If the pouches become infected or inﬂamed—such as when stool or bacteria become trapped inside them—the con- dition 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 (see page 49) 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, vomit- ing, chills, cramping, and constipation. Diverticulitis is usually detected during a diagnostic examination such as a colonoscopy or a gastrointestinal (GI) series (see “Diagnostic Procedures,” page 282).
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 (see box on page
275) also may be required.