Irritable bowel syndrome (IBS)

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Irritable bowel syndrome (IBS) may be referred to as spastic colon, mucous colitis, spastic colitis, nervous stomach, or irritable colon.
IBS is a functional bowel disorder, conditions in which the bowel appears normal but does not function normally. IBS is fairly common and makes up 20 - 50% of visits to gastroenterologists (doctors who diagnose and treat digestive problems).
Lower abdominal pain, and bloating associated with alteration of bowel habits (constipation and/or diarrhea) and abdominal discomfort relieved with defecation are the most frequent symptoms.
The colon, which is about 5 feet long, connects the small intestine to the rectum and anus. The major function of the colon is to absorb water, nutrients, and salts from the partially digested food that enters from the small intestine. Colon motility (the contraction of the colon muscles and the movement of its contents) is controlled by nerves, hormones, and the colon muscles. These contractions move the contents inside the colon toward the rectum. During this passage, water and nutrients are absorbed into the body, and what is left over is stool. A few times each day contractions push the stool down the colon, resulting in a bowel movement. However, if the muscles of the colon, sphincters, and pelvis do not contract in the right way (as in IBS), the contents inside the colon do not move correctly, resulting in abdominal pain, cramps, constipation, a sense of incomplete stool movement, or diarrhea.
Most people can control their symptoms with diet, stress management, lifestyle modification and prescribed medications. For some people, however, IBS can be disabling. They may be unable to work, attend social events, or even travel short distances due to urgency to defecate (pass stool) and pain in the colon.
IBS commonly starts between the ages of 20 and 30, and is twice as common in women as in men. The frequency of the condition in the general population is estimated to be somewhere between 10 and 20%. Up to 70% of people suffering from IBS are not receiving medical care for their symptoms.
IBS tends to occur with other pain disorders, such as fibromyalgia (49% of patients also have IBS), chronic fatigue syndrome (51%), chronic pelvic pain (50%), and temporomandibular joint dysfunction (64%). IBS may also exist with psychiatric conditions, such as depression, bipolar (manic/depressive disorder), and anxiety.
The syndrome can be divided into four main types, depending on which symptom is reported. Symptoms include abdominal pain, diarrhea, constipation, or diarrhea alternating with constipation. The abdominal pain type is usually described in a patient as either diarrhea-predominant (IBS-D), constipation-predominant (IBS-C) or IBS with alternating stool pattern (IBS-A). In some individuals, IBS may have a sudden onset and develop after an infectious illness characterized by two or more of the following: fever, vomiting, acute diarrhea or positive stool culture. This post-infective syndrome has consequently been termed "post-infectious IBS" (IBS-PI).
Chronic functional abdominal pain (CFAP) is quite similar to, but less common than, IBS. CFAP can be diagnosed if there is no change in bowel habits (constipation, diarrhea).
IBS is diagnosed by its signs and symptoms and by the absence of other diseases such as Crohn's disease, ulcerative colitis, and irritable bowel syndrome. These three diseases are inflammatory bowel conditions, whereas the colon is not inflamed in IBS. IBS does not seem to harm the intestines and does not lead to cancer.

Related Terms

Borborygmi, bowel, celiac disease, chronic fatigue syndrome (CFS), chronic functional abdominal pain (CFAP), colitis, colonoscope, colonoscopy, computerized tomography (CT), Crohn's disease, defecation, diarrhea, digestion, digestive, fibromyalgia, fiber, food allergy, gastrointestinal, hydrogen breath test, infection, inflammatory bowel disease (IBD), laxative, lactose, Rome II criteria, scleroderma, stool, sigmoidoscope, sigmoidoscopy, stress, stricture, temporomandibular joint dysfunction (TMJ).