Irritable Bowel

In medicine (gastroenterology), irritable bowel syndrome (IBS) or spastic colon is a group of functional bowel disorders which are fairly common and make up 20–50% of visits to gastroenterologists. There are three forms, dependent on which symptom predominates: diarrhea-predominant (IBS-D), constipation-predominant (IBS-C) and IBS with alternating stool pattern (IBS-A). An important new IBS subtype, post-infectious IBS (IBS-PI), is drawing much clinical investigation.

Features
Symptoms of IBS are abdominal pain or discomfort associated with changes in bowel habits in the absence of any apparent structural abnormality. The pain is typically relieved by defecating.

There appears to be an overlap of IBS with stress, chronic pelvic pain, fibromyalgia and various mental disorders (in a small minority). While no good explanation for this phenomenon exists, it does strengthen the view that there is a neurological and psychological component to IBS.

Hormones play a role in IBS that is not yet fully understood. Menstruation frequently triggers or exacerbates IBS symptoms (Heitkemper, 2003), while pregnancy and menopause can either worsen or improve symptoms. Hormone replacement therapy is associated with an increased risk of developing IBS (Maturitas, 2003).

Diagnosis

Diagnostic criteria
In 1978 Manning et al., found, from questionaire data, that IBS sufferers reported four common symptoms. The Manning Criteria was established to distinguish organic causes for symptoms from those of IBS. In 1992 the Rome I Criteria was established by a multinational committee of specialists, which further refined the Manning Criteria. In 1998 the Rome Working Team proposed changes to the definition and diagnostic criteria for IBS to reflect new research data, and to improve clarity.

The diagnosis of Irritable Bowel Syndrome has relied on a diagnosis of exclusion. Because the symptoms of IBS share the symptoms of so many other intestinal illnesses, it sometimes takes years before a correct diagnosis is made to exclude the obvious, and not so obvious, conditions which present symptoms similar to IBS.

Physicians rely on a variety of procedures and laboratory tests to confirm a diagnosis. The Rome II Criteria, however now defines markers which allows professionals to diagnose IBS after a careful examination of a sufferers medical history and physical abdominal examination which looks for any 'red flag' symptoms.

Red Flag symptoms which are NOT typical of IBS:

Pain that awakens/interferes with sleep
Diarrhea that awakens/interferes with sleep
Blood in your stool (visible or occult)
Weight loss
Fever
Abnormal physical examination
According to the Rome II consensus conference of the American Gastroenterological Association and international medical societies on functional bowel disorders, the diagnosis of IBS can be made when the following criteria are fulfilled:

At least 12 weeks, which need not be consecutive, in the preceding 12 months of abdominal discomfort or pain that has 2 of 3 features:

Relieved with defecation; and/or
Onset associated with a change in frequency of stool; and/or
Onset associated with a change in form (appearance) of stool.
Symptoms that cumulatively support the diagnosis of IBS

Abnormal stool frequency (for research purposes, “abnormal” may be defined as greater than 3 bowel movements per day and less than 3 bowel movements per week);
Abnormal stool form (lumpy/hard or loose/watery stool);
Abnormal stool passage (straining, urgency, or feeling of incomplete evacuation);
Passage of mucus;
Bloating or feeling of abdominal distention.
Supportive Symptoms of IBS:

Fewer than three bowel movements a week
More than three bowel movements a day
Hard or lumpy stools
Loose (mushy) or watery stools
Straining during a bowel movement
Urgency (having to rush to have a bowel movement)
Feeling of incomplete bowel movement
Passing mucus (white material) during a bowel movement
Abdominal fullness, bloating, or swelling

One of the most important therapeutic measures is reassuring the patient that she has no fatal or otherwise threatening disease, as this is the major concern of patients seeking medical help. Dietary advice may be given and medication is an option in most forms.

Halpert et al (2006), developed and fielded a questionnaire to identify patients’ perceptions about IBS, their preferences on the type of information they need, as well as educational media and expectations from health care providers. Responses from patients with IBS revealed misperceptions about IBS developing into other conditions, including colitis, malnutrition and cancer. The survey found IBS patients were most interested in learning about foods to avoid (60 percent), causes of IBS (55 percent), medications (58 percent), coping strategies (56 percent), and psychological factors related to IBS (55 percent). The respondents indicated that they wanted their physician to be available via phone or e-mail following a visit (80 percent) and have the ability to listen (80 percent), provide hope (73 percent) and support (63 percent).

Diet
There is no evidence that digestion of food or absorption of nutrients is different in those with IBS compared to those without IBS. However, the very act of eating can provoke an over-reaction of the gastrocolic response in those with IBS due to their heightened visceral sensitivity, and this can lead to abdominal pain, diarrhea, and/or constipation. Although the exact cause of IBS is not known, there are dietary factors that appear to aggravate symptoms or make a person feel worse. While dietary factors do not cause IBS, they often aggravate symptoms.(IFFGD, 2004).

Definitive determination of dietary issues can be accomplished by testing for the physiological effects of specific foods. The ELISA food allergy panel can identify specific foods to which a patient has a reaction. Other testing can determine if there are nutritional deficiencies secondary to diet that may also play a role.

There are a number of diet changes a person with IBS can make to prevent the over-reaction of the gastrocolic reflex and lessen pain, discomfort and bowel dysfunction. Having soluble fiber foods and supplements, substituting soy or rice products for dairy, being careful with fresh fruits and vegetables that are high in insoluble fiber, and eating regular small amounts can all help to lessen the symptoms of IBS (Van Vorous 2000). Foods and beverages to be avoided or minimized include red meat, oily or fatty (and fried) products, dairy (even when there is no lactose intolerance), solid chocolate, coffee (regular and decaffeinated), alcohol, carbonated beverages (especialy those also containing sorbitol) and artificial sweeteners (Van Vorous 2000). Several of the most common dietary triggers are well-established by clinical studies at this point; research has shown that IBS patients are hypersensitive to fats, insoluble fibers, and fructose (Caldarella, 2005; Whorwell, 1994; Young Choi, 2003). It also appears that some foods are more difficult for the gut as evidenced by elevated food-specific IgG4 antibodies being present (Kumar, 2005), while others increase colonic contractions, which may be painful, due to increased visceral sensitivity in IBS sufferers (Mayer, 2004).

Medication
Medications may consist of stool softeners and laxatives in constipation-predominant, and antidiarrheals (loperamide) in diarrhea-predominant IBS for mild symptoms. The use of antispasmodic drugs (e.g. anticholinergics such as hyoscine) has not shown conclusive beneficial results due to a large number of individuals who respond to the placebo effect; however, in general, although the cause is unknown, the placebo effect remains higher than normal for sufferers of IBS for all medications.

Low dosage of tricyclic and SSRI antidepressants have shown to be the most widely prescribed medications for helping to relieve symptoms of visceral sensitivity (pain) and diarrhea or constipation respectively. Newer drugs include alosetron, a selective 5-HT3 antagonist for IBS-D, which is only available for women in the United States under a restricted access program, due to severe risks of side-effects if taken mistakenly by IBS-A or IBS-C sufferers. Cilansetron, also a selective 5-HT3 antagonist, is undergoing further clinical studies in Europe for IBS-D sufferers. In 2005, Solvay Pharmaceuticals withdrew Cilansetron from the United States regulatory approval process after receiving a "not-approvable" action letter from the FDA requesting additional clinical trials. Tegaserod, a selective 5-HT4 antagonist for IBS-C, is available for relieving IBS constipation in women and chronic idiopathic constipation. The USA FDA has issued two warnings about the serious consequences of Tegaserod. In 2005, Tegaserod was rejected as an IBS medication by the European Union; however, it is available in some other countries.

Enteric coated peppermint oil capsules have been shown to relieve IBS symptoms in adults and children (Hadley, 2005), but they are contraindicated in patients with the comorbidity of gastroesophageal reflux disease.