Irritable bowel syndrome (IBS) is largely classified as a condition of exclusion. In other words, IBS is usually diagnosed after all other causes of symptoms such as infection or disease are ruled out. This is costly, time consuming, and very inconvenient for patients as well as physicians. In the late '70s and early '80s researchers began to look more closely at IBS as a serious disorder and not just a psychosomatic problem.
The first attempt at classifying the symptoms of IBS is known as the Manning Criteria. It was later discovered that these criteria are not specific enough and are unreliable for use with men who have IBS. Despite these shortcomings, the Manning Criteria are a very important step in defining symptoms of IBS.
The Manning Criteria are:
- Onset of pain linked to more frequent bowel movements
- Looser stools associated with onset of pain
- Pain relieved by passage of stool
- Noticeable abdominal bloating
- Sensation of incomplete evacuation more than 25% of the time
- Diarrhea with mucous more than 25% of the time
At the 13th International Congress of Gastroenterology in Rome, Italy in 1988 a group of physicians defined criteria to more accurately diagnose IBS. Known as the "Rome Criteria," this set of guidelines that outlines symptoms and applies parameters such as frequency and duration make possible a more accurate diagnosis of IBS.
The Rome criteria are:
- 3 months of continuous or recurring symptoms of abdominal pain or irritation that
- May be relieved with a bowel movement,
- May be coupled with a change in frequency, or
- May be related to a change in the consistency of stools.
- Two or more of the following are present at least 25 percent (one quarter) of the time:
- A change in stool frequency (more than 3 bowel movement per day or fewer than 3 bowel movements per week)
- Noticeable difference in stool form (hard, loose and watery stools or poorly formed stools)
- Passage of mucous in stools
- Bloating or feeling of abdominal distention
- Altered stool passage (e.g. sensations of incomplete evacuation, straining, or urgency)
Symptoms in the Rome Criteria are not the only indicators of IBS. Extra intestinal symptoms include:
- Full sensation after even a small meal
The Rome Criteria were not widely accepted when originally presented, but were better received after their first revision. This second version, created in 1992 and known as Rome II, added a length of time for symptoms to be present and pain as an indicator. The second revision, known as Rome III, is currently underway.