Irritable Bowel Syndrome Diagnosis

  • Diagnosis

    Irritable bowel syndrome (IBS) is a disorder of the lower digestive tract that results in abnormal bowel habits and abdominal pain/discomfort. People with IBS suffer from recurrent episodes of abdominal pain coupled with diarrhea and/or constipation. “Spastic colitis,” “irritable colon,” and “nervous stomach” are names for the problem. The majority of patients simply endure their symptoms, never bothering to seek help from a doctor. Others are so plagued by the disorder that they are reluctant to leave home during an attack because they are in too much pain, or else they fear they will not being able to find a bathroom quickly enough.

    In irritable bowel syndrome, the muscles of the bowel wall go into spasm. During normal digestion, regular contractions of the muscles in the wall of the digestive tract propel contents along—an action called peristalsis. In IBS, however, this motion (or motility) is hindered by spasms that result in diarrhea or constipation. While things like diet and stress can trigger intestinal spasms, the root of the problem appears to be the way the brain and bowel communicate. Recent research suggests that IBS patients have a more heightened awareness of pain in their digestive systems than do people without IBS. This sensitivity seems to be what triggers the intestinal spasms, and is the basis of abdominal pain/discomfort.

    Although IBS has a number of symptoms, including diarrhea and constipation, one symptom typically predominates Table 01. Sometimes diarrhea is the chief complaint during an irritable bowel attack. In such cases, patients may feel a strong need to relieve themselves many times throughout the day, and then pass loose, watery stools. When constipation predominates, patients may have fewer than three bowel movements a week, and pass small, hard stools after straining on the toilet. Some IBS patients experience alternating bouts of diarrhea and constipation.

    Others with irritable bowel feel as though they are not able to void completely. They may also feel full and bloated, and pass excessive amounts of gas. Most patients experience some degree of abdominal pain or discomfort that usually is relieved after a trip to the bathroom.

    Table 1.   Characteristics of IBS

    Diarrhea-predominant IBS
    More than three bowel movements per day
    Loose watery stools
    Urgency more than 25% of the time
    Pain-predominant IBS
    Abdominal pain
    Cramping or aching that is relieved by a bowel movement or flatulence
    Bloating-predominant IBS
    Feeling full or bloated
    Excessive flatulence
    Predominant rectal dissatisfaction
    Feeling of incomplete bowel voiding
    Constipation-predominant IBS
    Fewer than three bowel movements per week
    Lumpy hard stools
    Straining during bowel movements
    IBS with alternating bowel habit
    Alternating episodes of diarrhea and constipation

    About 15% of Americans have IBS, but many do not seek treatment. Although IBS affects both sexes, it is reported more frequently in women. Women with IBS seem to have more symptoms during their menstrual periods, which suggests that reproductive hormones may increase IBS symptoms. Although it has long been thought that anxiety, depression, and other mental illnesses were more common in those with IBS, recent studies have found this to be untrue. The psychological distress doctors assumed was the cause of IBS actually appears to be the result of coping with the overwhelming negative impact IBS can have on one's life. Reliable research now suggests IBS to be strictly a physical problem that is sometimes accompanied by a psychosocial component.

    To determine what is causing your symptoms, your doctor will start with a medical history. Since there are no definite physical signs of IBS in the colon, your doctor will make a diagnosis based solely on your description of symptoms rather than through examinations, x-rays, or blood tests. If you experience at least three months of constant or recurrent abdominal pain and discomfort that is relieved by a bowel movement, in addition to changes in frequency or consistency of stool, you fulfill the criteria for IBS. Though physical exams usually are not very revealing, your abdomen may be swollen and feel tender when touched.

    Diagnostic tests may be used to rule out other illnesses. Abdominal pain, diarrhea, and constipation can signal an array of conditions. Therefore, your doctor may wish to obtain a stool sample to check for a thyroid problem, hidden blood that could indicate colon cancer, or evidence of another medical problem. He or she may order a sigmoidoscopy or colonoscopy to look for signs of inflammatory bowel disease or intestinal cancer. Sigmoidoscopy and colonoscopy are tests in which a thin flexible tube is inserted into the rectum and used to inspect the inner lining of part or all of the bowel.

    While there is no way to prevent IBS, symptoms can be managed with the self-care measures described below.

  • Prevention and Screening

    While there is no way to prevent IBS, symptoms can be managed with the self-care measures described below.

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