DiagnosingIBS.doc

Diagnosing Irritable Bowel SyndromeA Changing Clinical ParadigmPhillip K. Henderson, DO, Jack A. DiPalma, MDSouth Med J. 2011;104(3):195-199. Abstract and IntroductionAbstractRather than being a diagnosis of exclusion, irritable bowel syndrome (IBS) is a diagnosis that can be identified by symptom-based criteria. The collection of these criteria by a meticulous history can be enhanced by using various tools. Once a positive diagnosis is made, using clinical criteria for diagnosis, one should look for alarm or warning symptoms or signs, and should characterize the type of bowel habit. Determining whether the condition is a diarrhea-predominant or a constipation-predominant IBS will direct further diagnostic evaluation and management.IntroductionIrritable bowel syndrome (IBS) is among the most common gastrointestinal disorders in North America, with a 1530% prevalence.13 It is a functional bowel disorder characterized by recurrent abdominal discomfort, which may be improved with defecation, and is associated with changes in stool frequency or form. The chronic nature of this condition and its severity has a notable impact on a patients quality of life and healthcare utilization.4,5 Many IBS patients dont seek care, and when they do, a diagnosis can be challenging. In the absence of specific biological markers or pathognomonic tests, the diagnosis is based on symptoms. Oftentimes, clinicians consider a diagnosis of IBS when a diagnostic evaluation is performed and is negative. This review will discuss a positive approach to IBS which utilizes clinical criteria for diagnosis.Symptom or SyndromeIBS is one of several functional gastrointestinal disorders; there are several other functional pain disorders such as fibromyalgia, chronic pelvic pain, and interstitial cystitis.3 The symptoms IBS patients experience are common and can be seen in normal individuals. W. Grant Thompson described symptoms as personal experiences, and syndromes as groups of symptoms that are recognized as a diagnostic entity.6 He further proposed that symptom diagnostic criteria provide a means for patients, doctors, and researchers to identify and discuss syndromes that have no known structural basis.Clinical Criteria for DiagnosisIn the absence of a specific test for IBS, criteria have been devised to guide clinicians and researchers in making a diagnosis.7 Various authors and working groups have proposed clinical criteria to make a positive symptom-based diagnosis at the first interview in order to avoid exhaustive diagnostic testing.710 The presence of abdominal pain or discomfort, altered bowel habits, or bloating should prompt consideration of these criteria. The primary care provider can review the questions in the scoring systems and determine if the patient meets the criteria for diagnosis.Manning CriteriaIn 1978, Manning et al11 published the manuscript Towards Positive Diagnosis of Irritable Bowel. Their criteria showed symptoms more likely to be present in IBS subjects ().Table 1. Manning criteria adapted from Spiller and Manning Looser stool at onset of pain More frequent bowel movements at onset of pain Pain eased after bowel movements Visible distension Feeling of distension Mucus per rectumKruis ScoreThe Kruis Score was an iteration to improve the Manning criteria, and it introduced alarm symptoms and negative scores for findings which could suggest other conditions ().12Table 2. Kruis ScoreScoreScore 44 = IBSPain, flatulence, or bowel irregularity34Duration of symptoms 2 yr16Description of abdominal pain (burning to not so bad)23Alternating diarrhea and constipation14Red flagsAbnormal physical findings or history pathognomonic of other disease47ESR 10 mm/h13WBC 10950Anemia98History of blood in stool98Rome CriteriaAn international working group in Rome, Italy published refined criteria in 1990 (Rome I), which were simplified with updates in 1999 and 2006.1316 Current Rome III guidelines () are used for clinical diagnosis and standard-entry criteria for clinical trials.Table 3. Various Rome Consensus CriteriaInternational Congress of Gastroenterology (Rome) Criteria for diagnosis of IBSRome I criteria Continuous or recurrent symptoms for at least 3 months. Abdominal pain or discomfort, relieved with defecation and/or associated with change in frequency and/or consistency of stool; and An irregular (varying) pattern of defecation at least 25% of the time and (two or more of):1. Altered stool frequency (3 bowel movements per day or age 40 yr Family history colon cancer Nocturnal symptoms Fecal soilageValidation of Clinical Criteria for IBSControversy remains about the value and validation of symptom-based criteria.611 In general, these studies report a modest specificity of 70%, which is improved to 90% with consideration of red flag signs and symptoms.25Clinical Criteria in Primary CareDespite the paradigm trend towards a positive diagnosis of IBS, many providers still approach IBS as a diagnosis of exclusion.8 Primary-care providers who care for the bulk of IBS patients are largely unaware of the various IBS criteria.7,26 In primary care, helpful features more common in IBS patients identified were: less than 6 months of symptoms, frequent consultations, medically unexplained symptoms, and patients reporting that stress aggravates symptoms.Diagnostic ChallengesClinicians are often frustrated with the uncertainties of the diagnosis of IBS and patients report frustration with their overall healthcare experience. An effective clinician-patient relationship improves outcomes and satisfaction. This starts with the medical interview. Patients often dont volunteer information about bowel habits and open-ended questions can encourage discussion. An effective dialogue can provide the opportunity for them to fully report their symptoms and voice their concerns. One should ask the patient what their expectations are from their visit. Clinicians have a tendency to interrupt patients within the first 20 seconds of the interview. Allowing a full description of the complaint adds only a few minutes to the visit. lists advice to enhance the clinician-patient therapeutic relationship.27Table 5. Guidelines to establish a therapeutic relationship1. Obtain patient history using a patient-centered approach.2. Conduct a careful examination of the patient.3. Determine the patients understanding and identify concerns about the illness.4. Explain the disorder to the patient.5. Identify and realistically address patient expectations for therapy.6. Provide a link between stressors and symptoms (when possible).7. Establish limits with the patient.8. Involve the patient in treatment decisions.9. Make recommendations based on patients interest and concerns.10. Establish a long-term relationship.CharacterizationOnce the diagnosis of IBS is made, based on clinical criteria, the bowel predominance should be characterized as diarrhea-predominant IBS (D-IBS), constipation-predominant (C-IBS), and alternators or mixed. Further testing or therapeutic interventions can be guided with this characterization. The Bristol stool scale can be helpful to distinguish types (). Patients who have pain as a predominant symptom may be managed with agents to focus on relief of discomfort, such as serotonin-reuptake inhibitors or tricyclic anti-depressants.1,3 However, they will benefit from distinguishing the bowel-habit type, since the diagnostic approach may vary based on type and effective treatment regimens available for specific bowel-predominant type.Table 6. Bristol-Stool ScaleD-IBSSome authors advise special additional testing for diarrhea-predominant IBS. Specifically, testing is advocated for lactose maldigestion, fructose malabsorption, bacterial overgrowth, celiac sprue, hyperthyroidism, and inflammatory bowel disease, including microscopic colitis. There is not a clear consensus as to the need for this testing. Our recent study showed that additional testing for D-IBS is not routinely performed, and that when it is performed, the yield is low other than for lactose maldigestion, which has previously been shown not to alter the course of IBS or its symptoms (Manolakis, unpublished data). It may be prudent to advise additional testing for those who dont respond to D-IBS-directed treatment.The prevalence, based on lactulose breath tests, of bacterial overgrowth in IBS varies, but it is common enough to warrant consideration.28 Testing methodology is limited, and some experts advise empiric treatment. Rifaximin is a poorly-absorbed antibiotic that seems to have preferred efficacy compared to amoxicillin-clavulimic acid, doxycycline, neomycin, or metronidazole. Sustained relief with IBS symptoms, particularly bloating, has been seen.29 Probiotics and medicinal bulk agents are used.30 Alosetron hydrochloride (HCl) is a 5-HT3 antagonist that increases colonic compliance, enhances absorption, and increases colonic transit time. It is approved for D-IBS. Concern for complications of constipation and ischemic colitis appear to be mitigated since the introduction of a risk-management plan in 2002.31C-IBSExcess methane production found on lactose or lactulose breath testing correlates with the severity of constipation.32 When found, methane-overgrowth therapy with rifaximin plus neomycin improved clinical symptoms and methane elimination.33 C-IBS treatments may be focused on bowel function with laxatives, including medicinal bulk, Magnesium hydroxide, or PEG 3350, or they may only be IBS-specific. Lubiprostone reduces the IBS symptoms of abdominal pain or discomfort, altered bowels habits, and other IBS symptoms. It is approved for chronic constipation and C-IBS.34 Linaclotide acetate and prucalopride are promising agents under review.35Clinical Approach to IBSWhen a patient presents with abdominal pain or discomfort, altered bowel habits or bloating, one should consider the diagnosis of IBS. Evaluation begins with a meticulous history addressing the multiple symptoms, age of onset, and quality of life. The interview should be adequate to collect the information necessary to fulfill the symptom-based clinical criteria for diagnosis. It is helpful to use tools like IBS Jennifer and the Bristol Stool Scale to accurately and sufficiently collect the historical data.The patient should be asked about family history of celiac disease, colon cancer, and inflammatory bowel disease (Crohns or ulcerative colitis). They should list current medications and prior successful or unsuccessful interventions. Patients should be directly asked about alternative and complementary medications.An inquiry should be made about red flag, alarm, or warning symptoms or signs, such as rectal bleeding, anemia, weight loss, fever, nocturnal symptoms, or fecal soilage. Colon cancer screening is based on age and risks, such as family history and pre-disposing conditions, like ulcerative colitis.Once a positive diagnosis is made, based on clinical symptom-based criteria, characterization as either D-IBS or C-IBS is helpful to direct further diagnostic evaluation and treatment.SidebarKey Points IBS is diagnosed by symptom-based clinical criteria. A positive diagnosis using clinical criteria can avoid exhaustive diagnostic testing. Characterizing the bowel habit as diarrhea- or constipation-predominant will direct further diagnostic evaluation and management.References1. American College of Gastroenterology Task Force on Irritable Bowel Syndrome; Brandt LJ, Chey WD, Foxx-Orenstein AE, et al. An evidence-based position statement on the management of irritable bowel syndrome. Am J Gastroenterol 2009;104:S1S35.2. Higgins PD, Johanson JF. Epidemiology of constipation in North America: a systematic review. Am J Gastroenterol 2004;99:750759.3. Mayer EA. Irritable bowel syndrome. N Engl J Med 2008;358:16921699.4. Irvine EJ, Ferrazzi S, Pare P, et al. Health-related quality of life in functional GI disorders: focus on constipation and resource utilization. Am J Gastroenterol 2002;97:19861993.5. Longstreth GF, Wilson A, Knight K, et al. Irritable bowel syndrome, health care use and costs: a U.S. managed care perspective. Am J Gastroenterol 2003;98:600607.6. Thompson WG. Symptoms and syndromes. Am J Gastroenterol 2010;105:714717.7. Spiller R, Camilleri M, Longstreth GF. Do the symptom-based, Rome criteria of irritable bowel syndrome lead to better diagnosis and treatment outcomes? Clin Gastroenterol Hepatol 2010;8:125136.8. Jellema P, Van Der Windt DA, Schellevis FG, et al. Systematic review: accuracy of symptom-based criteria for diagnosis of irritable bowel syndrome in primary care. Aliment Pharmacol Ther 2009;30:695706.9. Camilleri M. The con argument. Clin Gastroenterol Hepatol 2010;8:129131.10. Longstreth GF. Symptoms and tests for irritable bowel syndrome: diagnosing a complex disorder. Clin Gastroenterol Hepatol 2010;8:132136.11. Manning AP, Thompson WG, Heaton KW, et al. Towards positive diagnosis of the irritable bowel. Br Med J 1978;2:653654.12. Kruis W, Thiem C, Weinzierl M, et al. A diagnostic score for the irritable bowel syndrome: its valuate in the exclusion of organic disease. Gastroenterology 1984;87:17.13. Thompson WG, Longstreth GF, Drossman DA, et al. Functional bowel disorders and functional abdominal pain. Gut 1999;45(suppl 2):II43II47.14. Longstreth GF, Thompson WG, Chey WD, et al. Functional bowel disorders. Gastroenterology 2006;130:14891491.15. Drossman DA. The functional gastrointestinal disorders and the Rome II process. Gut 1999;45(suppl II):II1II5.16. Drossman DA. The functional gastrointestinal disorders and the Rome III process. Gastroenterology 2006;130:13771390.17. Adeniji OA, Barnett CB, DiPalma JA. Durability of the diagnosis of irritable bowel syndrome based on clinical criteria. Dig Dis Sci 2004;49:572574.18. Owens DM, Nelson DK, Talley NK. The irritable bowel syndrome: long-term prognosis and the physician-patient interaction. Ann Intern Med 1995;122:107112.19. Tolliver BA, Herrera JL, DiPalma JA. Evaluation of patients who meet clinical criteria for irritable bowel syndrome. Am J Gastroenterol 1994;89:176178.20. Corlew-Roath M, DiPalma JA. Clinical impact of identifying lactose maldigestion or fructose malabsorption in irritable bowel syndrome or other conditions. South Med J 2009;102:10101012.21. Hamm LR, Sorrells SC, Harding JP, et al. Additional investigations fail to alter the diagnosis of irritable bowel syndrome in subjects fulfilling the Rome criteria. Am J Gastroentero