Doctors call irritable bowel syndrome, or IBS, a functional disorder of the colon, not a disease, because symptoms occur in the absence of identifiable metabolic or anatomic disease. Not surprisingly, colonic symptoms of IBS, including diarrhea, constipation, flatulence, mucousy stools and feeling of incomplete defecation, predominate in the spectrum of patient complaints. However, IBS causes other symptoms that cannot be directly attributed to the colon.
Abdominal Pain
Abdominal pain is the hallmark of IBS and it figures prominently in the 2006 Rome Criteria used to diagnose IBS, according to the National Institutes of Health. Patients usually describe IBS abdominal pain as episodic and crampy, sometimes superimposed on a constant, dull ache. When asked to identify the location of their pain, most patients indicate the area around the belly button, even though the colon is usually lower and closer to the back, depending on the patient's position. Colon pain is felt in the abdomen because of the architecture of the human nervous system. Pain signals from the colon enter the spinal cord at the same level as nerves that supply the skin and muscles around the belly button, so most patients feel the pain in this area.
Upper GI Problems
In the 2008 edition of "Harrison's Principles of Internal Medicine," Dr. Chung Owyang, chief of gastroenterology for the University of Michigan Health System, reports that 25 to 55 percent of patients with IBS also complain of upper gastrointestinal tract problems such as nausea, vomiting, heartburn and upset stomach. According to Owyang, recordings of the contractions of the smooth muscles in the upper gastrointestinal tract reveal a high incidence of abnormalities in IBS patients. These abnormalities also follow the same pattern as IBS abnormalities within the colon. Namely, they occur almost exclusively during waking hours. This suggests that IBS represents a functional disorder of not just the colon, but the entire gastrointestinal tract.
Stress
Although stress undoubtedly triggers IBS, IBS also causes stress, particularly among people with severe cases. Several experts, including Owyang, acknowledge that IBS exerts a greater impact on quality of life than actual health. A 2010 study in the journal "Neurogastroenterology and Motility" offers some insight with the finding that IBS patients with high levels of social support fare better than their counterparts in terms of diminished stress and pain severity. Unfortunately, it's a catch-22 because, as noted in a 2005 report in the "American Journal of Managed Care," patients with IBS often miss work and avoid social situations because of discomfort or fear of embarrassment due to their symptoms, which limits their opportunities to obtain social support and contributes to a sense of isolation and job stress.
References
- Irritable Bowel Syndrome (Chapter); C. Owyang; In: "Harrison's Principles of Internal Medicine, 19th ed.;" A.S. Fauci et al.; 2008
- National Institutes of Health: What I Need to Know about Irritable Bowel Syndrome
- "Neurogastroenterology and Motility;" Perceived Social Support, Stress, and IBS in Severely Affected Patients; J.M. Lacknet et al.; May 2010
- "American Journal of Managed Care;" Impairment in Work Productivity and Health-Related Quality of Life in Patients with IBS; B.B. Dean et al.; Apr. 2005
