Oct 31, 2011 12:38 PM
Introduction
Irritable Bowel Syndrome (IBS) is the most common gastrointestinal disorder, affecting millions of people and takes a heavy toll in the healthcare budget. In the past, it was known by a variety of other names: spastic colon, spastic colitis, mucous colitis; and nervous or functional bowel. It is a disorder of the large intestine (colon), but other parts of the digestive system including small bowel, stomach & gall bladder can also be affected. 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 of the abdomen all the way to the rectum, storing it there until it can be evacuated. This movement occurs by rhythmic contractions of the colon.
The basic pathophysiology of IBS is very simple- the colon seems to contract in a disorganized, at times violent, manner. The contractions may be exaggerated and sustained, lasting for prolonged periods of time. These abnormal contractions result in changing bowel patterns (constipation, diarrhea or mucous in the stool), bloating & stomach pains. 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, if an operation is performed on the abdomen it would reveal a perfectly normal appearing bowel. 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 other times. IBS is extremely common and is present in perhaps half the patients that see Gastroenterologists. It tends to run in families. The disorder does not lead to cancer or any other serious illness. However, it may lead to diverticulosis, a disorder in which small balloon-like pockets develop from the bowel wall because of excessive, prolonged contractions.
Causes
The most common factor associated with the symptoms of IBS is the interaction between the brain and the gut. The bowel has a rich supply of nerves that are in communication with the brain. Virtually anyone has had, at one time or another, some alteration in bowel function when under intense stress, such as before an important athletic event, school examination, or a family conflict. People with IBS seem to have an overly sensitive bowel, and perhaps a super abundance of nerve impulses flowing to the gut, so that the ordinary stresses and strains of living somehow result in colon malfunction.
These exaggerated contractions can be demonstrated experimentally by placing pressure-sensitive devices in the colon. Even at rest, with no obvious stress, the pressures tend to be higher than normal in these individuals with IBS. With the routine interactions of daily living, these pressures tend to rise dramatically. When an emotionally charged situation is discussed, they can reach extreme levels not attained in people without IBS. These symptoms are due to real physiologic changes in the gut—a gut that tends to be inherently oversensitive, and one that overreacts to the stresses and strains of ordinary living. Also, certain foods, such as coffee, alcohol, spices, raw fruits, vegetables, and even milk, may cause the colon to malfunction. Infections, illness and even changes in the weather somehow can be associated with a flare-up in symptoms. So can the premenstrual cycle in the female.
Diagnosis
The major challenge is that a variety of serious diseases of the digestive system such as inflammation, cancer, and infection, can mimic some or all of the IBS symptoms. Investigations are helpful in making the diagnosis, including blood, and stool exams & endoscopy of the digestive tract. Additional tests may be required depending on the specific circumstances in each case.
Management
The management of IBS is directed both at the gut and the psyche. Current medical thinking about diet has changed a great deal in recent years. There is good evidence to suggest that, where tolerated, a diet rich in roughage/ bran/fiber is helpful. This diet can result in larger, softer stools, which seem to reduce the pressure generated in the colon. In addition to the fruits & vegetables, one can consume extra fiber by taking over the counter bulking agents such as psyllium mucilloid (Metamucil, Konsyl) or methylecellouse (Citrucel).As many have already discovered, the simple act of eating may, at times, activate the colon. This action is a normal reflex, although in IBS patients it tends to be exaggerated. It is sometimes helpful to eat smaller, more frequent meals to block this reflex.
There are certain medications like antispasmodics that can help the pain by relaxing the muscles in the wall of the colon, thereby reducing the bowel pressure. Since stress and anxiety may play a role in these symptoms, it can at times be helpful to use a mild sedative, often in combination with an antispasmodic. During physical exercise & meditation the bowel typically quiets down & these activities can be also helpful in relieving the symptoms.
Summary
Patients with IBS can be assured that nothing serious is wrong with the bowel once proper tests are done to rule out other serious diseases. Prevention and treatment may involve a simple change in certain daily habits, reduction of stressful situations, eating better and exercising regularly. Perhaps the most important aspect of treatment is reassurance. For most patients, just knowing that there is nothing seriously wrong is the best treatment of all, especially if they can learn to deal with their symptoms on their own.
Dr .Indran Indrakrishnan is a Gastroenterologist practicing in Lawrenceville , GA and a Clinical Associate Professor of Medicine at Emory University School of Medicine in Atlanta, GA. He is a past president of Georgia Gastroenterologic & Endoscopic Society and presently in the board of directors of Fight colorectal cancer, Georgia Association of Physicians of Indian Heritage and Third eye dancers. He is also a peer reviewer for the Georgia Composite State board of Medical Examiner. He is graduate of Georgia Physicians leadership academy of Medical Association of Georgia.
By Indran Indrakrishnan, MD
FRCP (London), FRCP (C), FACP, FACG
