IBS is the most commonly diagnosed gastrointestinal condition and the second most common cause for absenteeism from work in the United States.
Irritable bowel syndrome (IBS) is a gastrointestinal disorder characterized by chronic recurrent abdominal pain, altered bowel habits and disordered defecation associated with bloating, in the absence of an identifiable organic etiology.
• IBS is the most commonly diagnosed gastrointestinal condition and the second most common cause for absenteeism from work in the United States.
• IBS affects 10% to 15% of the population in the United States and Europe.
• IBS affects all ages but is more common in young women (2:1).
• Recurrent severe crampy abdominal pain that is not associated with signs of organic disease (bleeding, nocturnal symptoms, or weight loss in the absence of depression). This pain typically improves with defecation and worsens with eating. Stress can aggravate pain frequency or intensity.
• Change in bowel habits manifested as constipation, diarrhea, or alternating bouts of both is a very common clinical presentation. Constipation is associated with straining and incomplete evacuation. Diarrhea is preceded by urgency and can be associated with mucus.
• Bloating is common and can lead to frequent belching. Upper gastrointestinal symptoms and dyspepsia are also prevalent in patients with IBS.
• Conditions such as fibromyalgia, back pain, headaches, dyspareunia, dysuria, and sleep disturbances are more common among IBS patients.
• There is no curative approach. Once the diagnosis is established, treatment should focus on patient education, reassurance, psychological support, and modification of dietary factors that may worsen symptoms (caffeine use, poor fiber intake, lactose intolerance). Pharmacologic intervention is indicated for patients with symptoms that are affecting their quality of life.
• Using neuromodulating agents (such as tricyclic antidepressants) was found to be beneficial in decreasing pain and improving global symptoms of IBS. Tricyclic antidepressants should be used in doses smaller than those used for depression and should be titrated slowly. Selective serotonin reuptake inhibitors can also beused when patients have concomitant depression.
• The efficacy of antispasmodics (anticholinergics) in treating pain has been questioned in several metaanalyses. It is reasonable to use them on an as-needed basis, especially when pain is anticipated, eg, recurrent postprandial pain.
• Patients with diarrhea-predominant IBS may benefit from selective use of antidiarrheal agents such as loperamide. 5-hydroxytryptamine-3 (5-HT3) receptor antagonists are available for those refractory patients with severe diarrhea but only after informing the patient that these drugs can be associated with ischemic colitis.
• Women with constipation-predominant IBS may particularly benefit from the use of 5 hydroxytryptamine-4 (5-HT4) receptor agonists which stimulate colonic motility and decrease bowel sensitivity. IBS patients on tegaserod (Zelnorm) experience improvement in abdominal pain, bloating, and stool frequency. Unfortunately, tegaserod was recently removed from the market by the manufacturer because of concerns of cardiovascular complications related to its use.
• A few recent reports suggested that patients with bacterial overgrowth can benefit from the use of antibiotics. The main improvement noted was with bloating.
• The use of probiotics is gaining popularity as an adjunctive treatment method but large well designed studies proving their efficacy are lacking.