2005

Irritable Bowel Syndrome Patients Benefit From Comprehensive Care
at Mayo Clinic Motility Disorders Clinic

Points to Remember

• Irritable bowel syndrome (IBS) affects approximately 12% of adults in the United States, 70% of whom are women.
• Diagnosing and treating IBS patients can be challenging because differentiating between other gastrointestinal tract disease and IBS is difficult and responses to therapy vary.
• The Mayo Clinic Motility Disorders Clinic has advanced IBS diagnostic treatment and educational services.
• To improve understanding of the heritability of IBS, Mayo Clinic is enrolling patients and their families in a national clinical study.

Scope of Problem

Irritable bowel syndrome (IBS) is a common, chronic disorder, the mechanism of which is not well understood. Although not life-threatening, it can be profoundly life-changing because of the discomfort and stigma associated with its symptoms. IBS affects 12% of adults in the United States and prompts between 20% and 50% of referrals to gastroenterology clinics.

Seventy percent of IBS patients are women. Of those affected, half develop symptoms before the age of 35 years, and 40% develop symptoms between the ages of 35 and 50 years. Children also may develop IBS. New onset of IBS in the elderly is rare.

Nature of the Problem

Typical IBS symptoms include a change in frequency or appearance of stools, abdominal pain, bloating, diarrhea, constipation, or a combination of these. Chronic abdominal pain that is not associated with altered bowel habits is not IBS. IBS pain or discomfort can be disabling and interfere with school or job performance, family life, and leisure activities. Diagnosis of IBS can be challenging because IBS symptoms are common to other diseases, and no diagnostic test for IBS exists (Figure 1).

Standard IBS Treatments and Their Limitations

Most treatment centers on lifestyle and diet changes. Approximately 50% of patients with IBS report food intolerance.

However, there is no clear causal link between IBS and food, with 1 exception: lack of dietary fiber plays a role in constipation-predominant IBS. Stress management may benefit those with IBS. Over-the-counter laxatives and antidiarrheals provide relief in some cases.

For those whose symptoms do not respond to lifestyle changes or over-the-counter remedies, several types of prescription drugs are available. Two newer drugs are prescribed specifically for the treatment of IBS: tegaserod (Zelnorm) for constipation and alosetron (Lotronex) for diarrhea. Antispasmodic preparations such as dicyclomine (Bentyl) or hyoscyamine (Levsin, NuLev) also work in some patients. Most physicians agree new treatment options are needed.

Irritable bowel syndrome differential diagnosis possibilities.

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A New Approach: Comprehensive Motility Disorders Clinic

Mayo Clinic's Motility Disorders Clinic offers IBS patients an array of advanced diagnostic and educational services that are not often available elsewhere.

• An expanded specialty group of physicians, researchers, and allied health professionals dedicated to the diagnosis and treatment of IBS.
• Advanced diagnostic technologies developed at Mayo Clinic that characterize IBS, as well as a similar condition, functional dyspepsia.
1. Gastric emptying and gastrointestinal transit studies to measure the motility of the stomach, small bowel, and colon.
2. Gastric accommodation tests to determine how much the stomach expands after a meal.
3. Satiety tests, currently used only in research protocols, in which patients sip a nutrient drink at a defined rate as their feeling of fullness is measured.

For IBS patients whose main symptom is constipation, several tests can document anatomic and physiologic anomalies of the rectum.

• Anorectal angle x-ray: A radiolabeled substance is inserted into the rectum, and the anorectal angle is measured at rest, during squeeze, and during defecation to evaluate puborectalis muscle function.
• Defecating proctogram: In this radiologic test, the patient expels barium paste to determine whether there are anatomic abnormalities such as a rectocele and to assess whether pelvic floor dynamics are appropriate.
• Colonic manometry: This helps determine whether the colon is able to generate appropriate peristaltic contractions, or if it is atonic.
• Anorectal manometry: This test measures sphincter pressures, assesses rectal sensation, and evaluates a patient's ability to expel a rectal balloon.

Mayo Clinic helped pioneer diagnostic technologies that contribute to optimal management of irritable bowel syndrome.

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In addition to expanded testing services, Mayo Clinic's comprehensive IBS care includes patient education services. Taught by a multidisciplinary health care team, an IBS education class provides the latest information presented by a nurse educator, dietitian, physical therapist, and psychologist.

Clinical Study of Heritability of IBS

Mayo Clinic IBS specialists are conducting research aimed at improving diagnosis, treatment, and understanding of the disease. Mayo Clinic is now enrolling patients into a national study of the inheritance patterns of IBS funded by the National Institutes of Health and the American Gastroenterological Association. Researchers are studying family bowel symptoms to determine if IBS affects families and is under genetic control.

Patients are asked to complete a questionnaire about bowel habits and to provide a blood sample for DNA analysis. Researchers also ask permission to contact first-degree relatives and send them a questionnaire. Study participants need to travel to Mayo Clinic only once. The remainder of the study can be carried out long distance.

All patients who have received a diagnosis of IBS are eligible to enroll in the study. Patients who have other serious illnesses that disable them are ineligible, as are those who are unable to complete the questionnaire.