Diagnosis and management of irritable bowel syndrome

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Irritable bowel syndrome (IBS) is a relatively benign functional bowel disorder commonly encountered by family physicians on a daily basis. It is a compilation of several physiologic disturbances in the immune, neurologic, psychologic, and somatovisceral systems in the absence of a pathologic cause. The key characteristic symptoms of the condition include abdominal pain, bloating, and an alteration in the normal bowel pattern— either diarrhea or constipation, or a combination of both.1 Although considered benign, the condition can cause strife for the patient and can interfere with employment and other activities and can produce significant psychosocial dis- tress with decreased quality of life.

‌Epidemiology

IBS is an extremely common disorder, especially in North American and European populations. Estimates of its prevalence indicate that around 10% to 25% of people in the United States are affected by IBS.2-6IBS accounts for approximately20% to 25% of all visits to primary care physician offices.However, the reported percentage of the population affected byIBS is most likely underestimated, because it is believed that only one quarter of those suffering from IBS actually seek medical care. Despite this, IBS constitutes the most common diagnosis seen by gastroenterologists.7 It predominately affects women, with a female:male ratio of 2:1.8,9In addition, the average age of the presenting patient is 30 to 50 years old, with a significant decline in prevalence beyond age 60.6,10From an ethnical perspective, the incidence of IBS in the United States is equally distributed among Caucasians and African Americans and is lowest in the Hispanic population.11,12IBS prevalence on a global scale has significant fluctuation, in part because of the variance in definitions used by reporting countries for IBS (i.e., Manning vs Rome definitions). Despite these variances, the United States still has one of the highest reported incidences of IBS in the adult population (Table 1).

‌Pathophysiology

The exact pathophysiologic process of IBS is not well understood. It is clear that those processes responsible for altered bowel habits can occur in both healthy patients with IBS. Common etiologies seen as a culprit for altered gut functioning in IBS include inflammation, colon distention, types of meals (especially increased fat intake), and stress.14-16 In addition, infectious processes often cause colonic muscle hyperreactivity and alterations of the colon and small bowel. Some of the most common etiologies are listed in Table 2.

Recent research has focused on evaluating the role of serotonin in IBS. Serotonin is a key neurotransmitter in- volved in the secretory, sensory, and motor functions of the gut. There is evidence that abnormalities in brain-gut signaling and serotonin metabolism play a role in IBS.17 Further research is needed to determine the exact etiology of this process, however.

‌Diagnosis

‌Table 2 Common causes of gastrointestinal tract hypersensitivity

Meals: increased fat consumption Inflammation

Travel

Bacterial/Viral infection Psychosocial stress Abuse history

Alcohol use

Heavy physical activity

Obtaining a comprehensive medical history from and con- ducting a thorough physical examination on the patient are necessary to rule out the presence of underlying conditions or etiologies other than IBS. Symptoms that should prompt evaluation for alternate etiologies include family history of inflammatory bowel disease, heme-positive stools, weight loss, or new onset of IBS in patients older than age 50.18,19 A complete list is presented in Table 3.

In people who meet the IBS diagnostic criteria, the fol- lowing tests should be considered to exclude other diagno- ses: complete blood count, erythrocyte sedimentation rate, C-reactive protein, endomysial antibodies (for celiac dis- ease), stool microscopy and culture (for infectious condi- tions), liver function tests, ultrasound (to exclude choleli- thiasis or other biliary tract disease), and endoscopy with biopsies (to exclude peptic ulcer disease, celiac disease, inflammatory bowel disease, and malignancies).

Once the presence of significant etiologies has been ruled out, other simplified criteria can be used to diagnose IBS. Manning et al. published the first set of criteria in 1976, used for the diagnosis of IBS. In 1988, in an attempt to standardize definitions, an international working team pub- lished a consensus definition called the Rome criteria, which were later revised in 1992 (Rome II) and in 2005 (Rome III), which better defined specific criteria for the diagnosis of IBS. The Rome criteria have become the standard defi- nition used in the diagnosis of IBS. The Rome III criteria are summarized in Table 4.20 In addition to the standard defi- nition in the Rome criteria, there are several ancillary symp- toms commonly found in IBS patients:

• abnormal stool frequency (<3 bowel movements per week or >3 bowel movements per day)

• abnormal stool form (lumpy/hard or loose/watery)

• defecation straining, urgency, or a feeling of incomplete bowel movement

• passing mucus

• bloating

Table 3 Red flags that may suggest an alternate diagnosis18

Heme-positive stools Weight loss Antibiotic use

Family history of colon cancer or inflammatory bowel disease Symptom onset after 50 years old

Nocturnal gastrointestinal symptoms Fever

Abdominal/rectal masses

Low-density childhood living conditions (,1 person per room)18

‌Table 4 Rome III criteria for the diagnosis of IBS

Recurrent abdominal pain or discomfort† at least 3 days/ month in the last 3 months associated with two or more of the following:

1. Improvement with defecation

2. Onset associated with a change in frequency of stool

3. Onset associated with a change in form (appearance) of stool

Table 5 Treatment of IBS

Predominant irritable bowel symptom

Severity Constipation Diarrhea

Mild Physician Physician

education education

Pain

Physician education

Stress reduction Stress reduction Stress reduction Moderate Reassurance Reassurance Reassurance

Stress reduction Stress reduction Stress reduction Fiber Antidiarrheal

Laxatives agent

Severe Reassurance

Reassurance

Antispasmodic agent

TCA

Reassurance

Stress reduction Stress reduction Stress reduction Fiber Antidiarrheal Antispasmodic

Laxatives agent agent

TCA TCA TCA

Psychotherapy Psychotherapy Psychotherapy Antispasmodic Antispasmodic Antispasmodic

agent agent agent

TCA = tricyclic antidepressant.

‌Treatment

Effective treatment of IBS should revolve around the pre- dominant symptom experienced and the severity of the condition. Before initiating any treatment protocol, how- ever, the physician must establish a good rapport with the patient to maximize the treatment effect. Numerous studies have shown that effective reassurance on behalf of the physician leads to increased trust by the patient and de- creased office visits for IBS.21

For patients with only mildly severe symptoms, conser- vative therapy is usually effective. Evaluating the patient’s diet for precipitating factors (such as lactose intolerance, excessive caffeine, or the use of stimulant medications) may assist in revealing the underlying cause. Educating the pa- tient on these factors and eliminating them from the pa- tient’s diet can provide an immediate and simple resolution to the symptoms and improve clinical outcome.

IBS that is constipation-predominant and accompanied by moderate or severe discomfort can be effectively treated with increased fiber intake, either as a supplement or with a normal diet. Fiber increases the water content and increases the overall bulk of the stool.22 In addition, antispasmodic agents such as dicyclomine (Bentyl, Aptalis Pharmaceuti- cal, Birmingham, AL) and Hyoscyamine (Levsin, Alaven Pharmaceuticals, Marietta, GA) have been found to bring short-term relief, but have not been proved to be useful long term.23 Tegaserod (Zelnorm, Novartis, Basel, Switzerland), a medication approved for use in constipation-predominant IBS in 2000, was voluntarily removed by the manufacturer in 2007 because of the increased risk for heart attacks and strokes.

IBS that is diarrhea-predominant and moderate or severe in nature can be treated effectively with antidiarrheal agents such as loperamide (Imodium, McNeil Consumer Health- care, Fort Washington, PA). Studies have shown that lop- eramide will not typically reduce pain or bloating but is effective at reducing stool frequency and increasing the solidification of the stool form.24 Alosetron (Lotronex, GlaxoSmithKline, London, UK) is another medication ap- proved for diarrhea-predominant IBS with specific require- ments for its use in IBS.25 Alosetron is a selective 5-HT3 antagonist that selectively blocks 5-HT3 receptors, which are extensively distributed on enteric motor neurons and in peripheral afferents and central locations such as the vom- iting center. It has been approved for the treatment of women with severe diarrhea-predominant IBS who failed to

‌respond to conventional treatment. Alosetron was reintro- duced to the market in June 2002 after being initially with- drawn in November 2000 because of adverse effects includ- ing severe constipation and ischemic colitis.

IBS that is primarily pain-predominant and moderate or severe in nature is effectively treated with a tricyclic anti- depressant such as amitriptyline (Elavil, Merck, Whitehouse Station, NJ). Tricyclic antidepressant medications facilitate endogenous endorphin release, causing blockade of norepi- nephrine reuptake, leading to enhancement of descending inhibitory pain pathways, and the blockade of the pain neuromodulator serotonin.26

In addition to the above treatment modalities, several alternative and complementary therapies have been studied. Peppermint has antispasmodic activity and peppermint leaves secrete an oil with mild anesthetic properties, both of which help alleviate diarrhea and abdominal pain in IBS. A meta-analysis of several studies involving peppermint oil showed a statistically significant improvement of symptoms in IBS when compared with placebo.27 However, pepper- mint can cause significant heartburn and should be taken only if the benefits outweigh the risks. Other nontraditional therapies with unproven benefit in the IBS patient include ginger, fennel seeds, chamomile tea, evening primrose oil, and wormwood oil. A summary of the treatment regimens can be found in Table 5.

‌Osteopathic considerations

IBS can present as either constipation-predominant, diar- rhea-predominant, or both. As such, both the sympathetic and parasympathetic nervous systems can play a key role in

the progression of the condition. In IBS with primarily diarrhea, somatic dysfunctions of the occipitoatlanto and atlantoaxial joints, as well as the C2 vertebrae, are usually present as a result of increased tone of the vagus nerve. Tissue texture changes and tenderpoint at the transverse processes are common. Treatment of these counterstrain tenderpoints can reduce the stimulatory activity of the vagus nerve. Use of muscle energy techniques to facilitate the occipitoatlantal joint release provides significant improve- ment in the patient’s symptoms.28

In IBS with primarily constipation, somatic dysfunctions are typically found in the regions of the lower thoracic and upper lumbar vertebrae, caused by sympathetic stimulation by the celiac, as well as the superior and inferior, mesenteric ganglia. Treatment of tenderpoints on the transverse pro- cesses of these vertebra as well as muscle energy or high- velocity, low-amplitude treatments provides improved tran- sit of the gastrointestinal tract.28

A final osteopathic consideration should be to evaluate the pelvis and lower extremities for possible viscerosomatic findings involving Chapman’s reflexes. Findings of somatic dysfunctions involving the colon occur along the iliotibial band and can be effectively treated using typical myofascial release techniques.28,29 Restoration of homeostatsis is the primary goal in any osteopathic treatment modality.

‌Summary

IBS is a common condition seen in the primary care setting. Although considered to be benign, IBS is a chronic bowel disorder presenting daily challenges and affecting a pa- tient’s quality of life. IBS signs and symptoms can vary greatly from patient to patient. Proper diagnosis and treat- ment using both osteopathic techniques as well as tradi- tional medications aimed specifically at the predominant symptom will lead to overall improved patient satisfaction. Education of the patient in the importance of stress reduc- tion along with a good physician-patient relationship can help the patient manage IBS symptoms and improve the overall psychosocial well-being of the patient.

‌References‌

1. ‌Olden KW: Irritable bowel syndrome: an overview of diagnosis and pharmacologic treatment. Clevel Clin J Med 70(Suppl 2):S3-S7, 2003

2. American College of Gastroenterology Functional Gastrointestinal Disorders Task Force: Evidence-based position statement on the man- agement of irritable bowel syndrome in North America. Am J Gastro- enterol 97(suppl):S1-S5, 2002

3. Mertz HR: Irritable bowel syndrome. New Engl J Med 349:2136-2146,

   2003

4. Brandt LJ, Bjorkman D, Fennerty MB, et al: Systematic review on the management of irritable bowel syndrome in North America. Am J Gastroenterol 97(suppl):S7-S26, 2002

5. ‌Drossman DA, Camilleri M, Mayer EA, et al: AGA technical review on irritable bowel syndrome. Gastroenterology 123:2108-2131, 2002

6. ‌Camilleri M, Choi MG: Review article: irritable bowel syndrome. Aliment Pharmacol Ther 11:3-15, 1997

7. ‌Talley NJ, Gabriel SE, Hamsen WS, et al: Medical costs in community subjects with irritable bowel syndrome. Gastroenterology 109:1736- 1741, 1995

8. Toner BB, Akman D: Gender role and irritable bowel syndrome: literature review and hypothesis. Am J Gastroenterol 95:11-16, 2000

9. Higgins PD, Johanson JF: Epidemiology of constipation in North America: a systematic review. Am J Gastroenterol 99:750-759, 2004

10. ‌Drossman DA, Whitehead WE, Camilleri M: Irritable bowel syn- drome: a technical review for practice guideline development. Gastro- enterology 112:2120-2137, 1997

11. Zuckerman MJ, Guerra LG, Drossman DA, et al: Comparison of bowel patterns in Hispanics and non-Hispanic whites. Dig Dis Sci 40:1761-1769, 1995

12. ‌Taub E, Cuevas JL, Cook EW, et al: Irritable bowel syndrome defined by factor analysis: gender and race comparisons. Dig Dis Sci 40:2647- 2655, 1995

13. ‌The World Gastroenterology Organisation Global Guidelines: Irritable bowel syndrome: a global perspective. April 20, 2009.

14. Serra J, Axpiroz F, Malagelada JR: Impaired transit and tolerance of intestinal gas in the irritable bowel syndrome. Gut 48:14-19, 2001

15. Rogers J, Henry MM, Misiewicz JJ: Increased segmental activity and intraluminal pressures in the sigmoid colon of patients with the irrita- ble bowel syndrome. Gut 30:634-641, 1989

16. ‌Welgan P, Meshkinpour H, Beeler M: Effect of anger on colon motor and myoelectric activity in irritable bowel syndrome. Gastroenterology 94:1150-1156, 1988

17. ‌Garvin B, Wiley JW: The role of serotonin in irritable bowel syn- drome: implications for management. Curr Gastroenterol Rep 10:363- 368, 2008

18. Paterson WG, Thompson WG, Vanner SJ, et al: Recommendations for the management of irritable bowel syndrome in family practice. CMAJ 161:154-160, 1999

19. ‌Drossman DA, Corazziari E, Talley NJ, et al: Rome II: the functional gastrointestinal disorders: diagnosis, pathophysiology, and treatment: a multinational consensus. Gut 45(Suppl 2):1-81, 1999

20. ‌Longstreth GF, Thompson WG, Chey WD, et al: Functional bowel disorders. Gastroenterology 130:1480-1491, 2006

21. ‌Owens DM, Nelson DK, Talley NJ: The Irritable bowel syndrome: long-term prognosis and the physician patient interaction. Ann Intern Med 122:107-112, 1995

22. ‌Friedman G. Diet and the irritable bowel syndrome. Gastroenterol Clin

    North Am 20:313-324, 1991

23. ‌Brandt LJ, Chey WD, Foxx-Orenstein AE, et al: An evidence-based position statement on the management of irritable bowel syndrome. American College of Gastroenterology Task Force on Irritable Bowel Syndrome. Am J Gastroenterol 104(Suppl 1):S1-S35, 2009

24. ‌Efskind PS, Bernklev T, Vatn MH: A double-blind placebo-controlled trial with loperamide in irritable bowel syndrome. Scand J Gastroen- terol 31:463-468, 1996

25. ‌Camilleri M, Northcutt AR, Kong S, et al: Efficacy and safety of alosetron in women with irritable bowel syndrome: a randomised, placebo-controlled trial. Lancet 355:1035-1040, 2000

26. ‌Gorard DA, Libby GW, Farthing MJ: Effect of a tricyclic antidepres- sant on small intestinal motility in health and diarrhea-predominant irritable bowel syndrome. Dig Dis Sci 40:86-95, 1995

27. ‌Pittler MH, Ernst E: Peppermint oil for irritable bowel syndrome: a critical review and meta-analysis. Am J Gastroenterol 93:1131-1135, 1998

28. Channell MK, Mason DC: The 5-Minute Osteopathic Manipulative Medicine Consult. Philadelphia: Lippincott Williams & Wilkins, 2009,

    pp. 88-89

29. Nelson KE, Glonek T: Somatic Dysfunction in Osteopathic Family Medicine. Philadelphia: Lippincott Williams & Wilkins, 2007