This document presents the official recommendations for the American Gastroenterological Association (AGA) on irritable bowel syndrome. It was approved by the AGA Patient Care Committee on October 5, 1996, and by the AGA Governing Board on November 10, 1996.
The following guidelines were developed to assist the physician in the diagnosis and management of patients with irritable bowel syndrome (IBS). They emanate from a comprehensive review of the medical literature pertaining to IBS.1 The IBS is a combination of chronic or recurrent gastrointestinal symptoms not explained by structural or biochemical abnormalities, which is attributed to the intestines and associated with symptoms of pain and disturbed defecation and/or symptoms of bloatedness and distension.
In the United States, most European countries, China, and Japan, IBS affects 14%-24% of women and 5%-19% of men, with a decrease in reporting frequency among older persons. The prevalence appears similar in whites and blacks, but may be lower in Hispanics. Although up to 70% of persons with IBS symptoms do not seek medical attention, it accounts for 12% of primary care and 28% of gastroenterological practice (41% of all functional gastrointestinal disorders). Persons with IBS miss three times as many work days, see physicians more often for gastrointestinal or nongastrointestinal complaints, and in one study, incurred annual health care costs of $742 (1992 dollars) compared with $429 for those without IBS.
Psychological stress exacerbates gastrointestinal symptoms in everyone, but to a greater degree in patients with IBS. Although psychological distress has no diagnostic value for IBS, its identification may help in planning psychological or psychopharmacological treatment.
Psychological and sociocultural factors modify illness experience and outcome, including pain reporting, physician visits, medication use, or the seeking of alternative medical treatment. Stressors having a strong effect on outcome include a history of physical or sexual abuse, major loss (e.g., death or divorce) and other major trauma. Therefore, patients with IBS seen at referral centers have greater psychological disturbances than IBS patients seen in primary care.
IBS adversely affects health-related quality of life, including impairment of physical and psychosocial function, disability, work absenteeism, and physician visits.
A diagnosis is based on identifying positive symptoms consistent with the condition (Table 1), and excluding in a cost-effective manner other conditions with similar clinical presentations.
A physical examination and the following studies are recommended for routine evaluation: complete blood count; sedimentation rate; chemistries; stool for ova, parasites, and blood; and flexible sigmoidoscopy or colonoscopy or barium enema with sigmoidoscopy if older than 50 years. Other diagnostic studies should be minimal and will depend on the symptom subtype. For example, in patients with diarrhea-predominant symptoms, a small bowel radiograph to rule out Crohn's disease, or lactose/dextrose H2 breath test, and if negative, a therapeutic trial of olperamide. For patients with constipation-predominant symptoms, a therapeutic trial of fiber supplement may be all that is required. For patients with pain as the predominant symptom, a plain abdominal radiograph during an acute episode to exclude bowel obstruction and other abdominal pathology, and if negative, a therapeutic trial of an antispasmodic may be indicated. The evaluation strategy may be modified by other factors, such as the duration and severity of symptoms, changes in symptom type or severity over time, and demographic or psychosocial factors.
Treatment can then be started and the patient's condition reevaluated in 3-6 weeks. If treatment is unsuccessful, or if further evaluation seems needed, additional studies based on symptom subtype can be performed at that time. Some tests may require referral to a major medical center.
The treatment strategy is based on the nature and severity of the symptoms, the degree of physiological disturbance and functional impairment, and the presence of psychosocial difficulties affecting the course of the illness. Patients with mild symptoms usually respond to education and reassurance and simple treatments not requiring prescription medication. A smaller proportion of patients with moderate symptoms have more disability and require pharmacological treatments directed at altered gut physiology or psychological treatments. A small proportion of patients with severe and refractory symptoms are frequently seen at referral centers, and have more constant pain and psychosocial disablement. They may require antidepressant treatment, psychological treatments and support, and in occasional cases, referral to a multidisciplinary pain center. The components of the treatment strategy include the following.
At least 3 months of continuous or recurrent symptoms of the following:
| |
General treatment approach. For all patients, the physician should establish an effective therapeutic relationship, provide patient education and reassurance, and help with dietary and lifestyle modifications when needed.
Medication directed at the predominant symptom(s). For pain and bloating, consider antispasmodic (anticholinergic) medication, particularly when symptoms are exacerbated by meals, or a tricyclic (TCA) or serotonin-reuptake inhibitor antidepressant (SSRI), particularly when pain is frequent or severe (see below).
For constipation, increased dietary fiber (25 g/day) is recommended for simple constipation, although its effectiveness is mixed, based on several studies in reducing pain in patients with constipation-predominant IBS. Similarly, cisapride has been proposed for constipation-predominant IBS based on only one study.
For diarrhea, loperamide (2-4 mg, up to four times daily) can reduce loose stools, urgency and fecal soiling, and in low doses, does not seem to have central nervous system effects. Cholestyramine may be considered for a subgroup of patients with cholecystectomy or who may have idiopathic bile acid malabsorption.
Psychological treatments. Psychological treatments are usually initiated when symptoms are severe enough to impair health-related quality of life. A patient may be referred to a mental health professional for treatment of associated psychiatric disorders, such as major depression or a history of abuse that interferes with adjustment to illness. To enhance patient motivation for psychological treatment, the physician should explain that along with the primary care physician, the mental health professional is part of a treatment team involved in the patient's overall plan of care.
Several psychological treatments have been studied in patients with IBS, including dynamic (interpersonal) psychotherapy, cognitive-behavioral treatment, hypnosis, relaxation, and biofeedback. These seem to be effective in reducing abdominal pain and diarrhea but not constipation, and they also reduce anxiety and other psychological symptoms. It is not known whether improvement in IBS symptoms relates to changes in gastrointestinal physiology or in the psychological interpretation of enteroceptive sensation. A positive response is associated with patients who relate symptom exacerbations to stressors, and have a waxing and waning of symptoms rather than chronic pain. There are no comparative data to determine which treatments are superior, and additional studies are needed to determine the relative efficacy of psychological treatments for various subgroups of patients.
Psychotropic medication. Antidepressants are recommended for severe or refractory symptoms of pain, and may be helpful for less severe symptoms. They have neuromodulatory and analgesic properties independent of their psychotropic effect, and these effects may occur sooner and in lower dosages than is the case when these drugs are used for treatment of depression. Most studies have evaluated treatment with tricyclic antidepressants (e.g., amitriptyline and desipramine), rather than SSRIs (e.g., fluoxetine, paroxetine, sertraline) in patients with IBS, and no comparative studies have been performed. However, the selective serotonin reuptake inhibitors are now in common use because of their low side effect profile and better safety than the tricyclic antidepressants. Anecdotal evidence suggests that they may be as effective as the trichloroacetic acids.
Anxiolytics are generally not recommended because of weak treatment effects, a potential for physical dependence, and interaction with other drugs and alcohol.
Address requests for reprints to: Chair, Patient Care Committee, AGA, 7910 Woodmont Avenue, 7th Floor, Bethesda, Maryland 20814. Fax: (301) 654-5920.
© 1997 by the American Gastroenterological Association