Irritable bowel syndrome (IBS) is an intestinal disorder that causes the following:

• crampy pain
• gassiness
• bloating
• changes in bowel habits

IBS has inaccurately been called by many names, including the following:

• colitis
• mucous colitis
• spastic colon
• spastic bowel
• functional bowel disease

IBS is called a functional disorder because there is no sign of disease when the colon is examined. Because physicians have been unable to find an organic cause, IBS often has been thought to be caused by emotional conflict or stress. While stress may worsen IBS symptoms, research suggests that other factors also are important.

IBS often causes a great deal of discomfort and distress, but it is not believed to:

• cause permanent harm to the intestines.
• lead to intestinal bleeding of the bowel.
• lead to a serious disease such as cancer.

It has not been shown to lead to serious, organic diseases, nor has a link been established between IBS and inflammatory bowel diseases such as Crohn's disease or ulcerative colitis.

The digestion and propulsion of nutrients and fluids through the gastrointestinal system (GI) is a very complicated and very well organized process. The GI tract has its own intrinsic muscles and nerves that connect, like an electrical circuit, to the spinal cord and brain. Neuromuscular events occurring in the GI tract is relayed to the brain through neural connections, and the response of the brain is also relayed back to the gastrointestinal tract. As a result of this activity, motility and sensation in the bowel is generated. An abnormality in this process results in a disordered propulsion of the intestinal contents, which generates the sensation of pain.

The person with IBS has a colon that is more sensitive and reactive than usual, so it responds strongly to stimuli that would not affect others. The colon muscle of a person with IBS begins to spasm after only mild stimulation or ordinary events such as the following:

• eating
• distention from gas or other material in the colon
• certain medications
• certain foods

Women with IBS seem to have more symptoms during their menstrual periods, suggesting that reproductive hormones can increase IBS symptoms.

• diet
  Eating causes contractions of the colon, normally causing an urge to have a bowel movement within 30 to 60 minutes after a meal. Fat in the diet can cause contractions of the colon following a meal. With IBS, however, the urge may come sooner, accompanied by cramps and diarrhea. 

• stress
  Stress stimulates colonic spasm in people with IBS. Although not completely understood, it is believed to be because the colon is partly controlled by the nervous system. Counseling and stress reduction techniques can help relieve the symptoms of IBS, however, this does not mean IBS is the result of a personality disorder. It is at least partly a disorder of colon motility.

• crampy abdominal pain
• painful constipation and/or diarrhea.
• alternating constipation and diarrhea
• mucus may be in the bowel movement

Bleeding, fever, weight loss, and persistent, severe pain are not symptoms of IBS, but indicate other problems. The symptoms of IBS may resemble other medical conditions or problems. Always consult your physician for a diagnosis.

• blood tests (to determine if you are anemic, have an infection, or have an illness caused by inflammation or irritation)
• urine analysis and culture (to help assess for urinary tract infections)
• stool culture - checks for the presence of abnormal bacteria in the digestive tract that may cause diarrhea and other problems. A small sample of stool is collected and sent to a laboratory by your physician's office. In two or three days, the test will show whether abnormal bacteria are present.
• fecal occult blood test - checks for hidden (occult) blood in the stool. It involves placing a very small amount of stool on a special card, which is then tested in the physician's office or sent to a laboratory; if blood is present, it may suggest an inflammatory source in the gastrointestinal tract.
• abdominal x-rays - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
• abdominal ultrasound - a diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels. Gel is applied to the area of the body being studied, such as the abdomen, and a wand called a transducer is placed on the skin. The transducer sends sound waves into the body that bounce off organs and return to the ultrasound machine, producing an image on the monitor. A picture or video tape of the test is also made so it can be reviewed in the future.
• esophagogastroduodenoscopy (Also called EGD or upper endoscopy.) - a procedure that allows the physician to examine the inside of the esophagus, stomach, and duodenum. A thin, flexible, lighted tube, called an endoscope, is guided into the mouth and throat, then into the esophagus, stomach, and duodenum. The endoscope allows the physician to view the inside of this area of the body, as well as to insert instruments through a scope for the removal of a sample of tissue for biopsy (if necessary).

• colonoscopy - a procedure that allows the physician to view the entire length of the large intestine, and can often help identify abnormal growths, inflamed tissue, ulcers, and bleeding. It involves inserting a colonoscope, a long, flexible, lighted tube, in through the rectum up into the colon. The colonoscope allows the physician to see the lining of the colon, remove tissue for further examination, and possibly treat some problems that are discovered.

• your age, overall health, and medical history
• extent of the condition
• your tolerance for specific medications, procedures, or therapies
• expectations for the course of the condition
• your opinion or preference

Treatment may include:

• changes in diet
  Eating a proper diet is important with irritable bowel syndrome. In some cases of IBS, a high-fiber diet can reduce the symptoms. Keeping a list of foods that cause distress, and discussing the findings with a physician or registered dietitian, can help.

• medication
  Physicians may prescribe fiber supplements or occasional laxatives. Some physicians prescribe antispasmodic medications, tranquilizers, or antidepressants to relieve symptoms.

The major concerns with medications for IBS are the potential for drug dependency and the effects the disorder can have on lifestyle. In an effort to control their bowels or reduce stress, some people become dependent on laxatives or tranquilizers.