Irritable Bowel Syndrome: What is it? What are the symptoms?

Medically, irritable bowel syndrome (IBS) is known by a variety of other terms: spastic colon, spastic colitis, mucous colitis and nervous or functional bowel disorder. Usually, it is a disorder of the large intestine (colon), although other parts of the intestinal tract -- even up to the stomach -- can be affected.

IBS is not a disease. Although the symptoms of IBS may be severe, the disorder itself is not a serious one. There is no actual disease present in the colon. In fact, an operation performed on the abdomen would reveal a perfectly normal appearing bowel.

Rather, it is a problem of abnormal function. The colon, the last five feet of the intestine, serves two functions in the body. First, it dehydrates and stores the stool so that, normally, a well-formed soft stool occurs. Second, it quietly propels the stool from the right side over to the rectum, storing it there until it can be evacuated. This movement occurs by rhythmic contractions of the colon.

When IBS occurs, the colon does not contract normally. instead, it seems to contract in a disorganized, at times violent, manner. The contractions may be terribly exaggerated and sustained, lasting for prolonged periods of time. One area of the colon may contract with no regard to another. At other times, there may be little bowel activity at all. These abnormal contractions result in changing bowel patterns with constipation being most common.

A second major feature of IBS is abdominal discomfort or pain. This may move around the abdomen rather than remain localized in one area. These dis-organized, exaggerated and painful contractions lead to certain problems. The pattern of bowel movements is often altered. Diarrhea may occur, especially after meals, as the entire colon contracts and moves liquid stool quickly into the rectum. Or, localized areas of the colon may remain contracted for a prolonged time. When this occurs, which often happens in the section of colon just above the rectum, the stool may be retained for a prolonged period and be squeezed into small pellets. Excessive water is removed from the stool and it becomes hard.

Also, air may accumulate behind these localized contractions, causing the bowel to swell. So bloating and abdominal distress may occur. Some patients see gobs of mucous in the stool and become concerned. Mucous is a normal secretion of the bowel, although most of the time it cannot be seen. IBS patients sometimes produce large amounts of mucous, but this is not a serious problem.

The cause of most IBS symptoms -- diarrhea, constipation, bloating, and abdominal pain -- are due to this abnormal physiology. The condition usually begins in young people, usually below 40 and often in the teens. The symptoms may wax and wane, being particularly severe at some times and absent at others. Over the years, the symptoms tend to become less intense.

IBS is extremely common and is present in perhaps half the patients that see a specialist in gastroenterology. It tends to run in families. The disorder does not lead to cancer. Prolonged contractions of the colon, however, may lead to Diverticulosis, a disorder in which balloon-like pockets push out from the bowel wall because of excessive, prolonged contractions.
The symptoms of IBS are diarrhea, abdominal pain, constipation and bloating. Irritable bowel syndrome is characterized by a group of symptoms in which abdominal pain or discomfort is associated with a change in bowel pattern, such as loose or more frequent bowel movements, diarrhea, and/or constipation.

Irritable Bowel Syndrome Symptoms
The signs and symptoms of irritable bowel syndrome can vary widely from person to person and often resemble those of other diseases. Among the most common are:

• Abdominal pain or cramping
• A bloated feeling
• Gas (flatulence)
• Diarrhea or constipation — people with IBS may also experience alternating bouts of constipation and diarrhea
• Mucus in the stool

For most people, IBS is a chronic condition, although there will likely be times when the signs and symptoms are worse and times when they improve or even disappear completely.

Causes of Irritable Bowel Syndrome
No one knows exactly what causes irritable bowel syndrome. The walls of the intestines are lined with layers of muscle that contract and relax as they move food from your stomach through your intestinal tract to your rectum. Normally, these muscles contract and relax in a coordinated rhythm. But if you have irritable bowel syndrome, the contractions are stronger and last longer than normal. Food is forced through your intestines more quickly, causing gas, bloating and diarrhea. In some cases, however, the opposite occurs. Food passage slows, and stools become hard and dry.

Some researchers believe IBS is caused by changes in the nerves that control sensation or muscle contractions in the bowel. Others believe the central nervous system may affect the colon. And because women are two to three times as likely as men to have IBS, researchers believe that hormonal changes also play a role. Also, many women find that signs and symptoms worsen during or around their menstrual periods.