IBS Patients Show Frequent Fluctuations Between Loose/Watery and Hard/Lumpy Stools: Implications for Treatment

Abstract

Aims To determine how variable stool consistency is in patients with irritable bowel (IBS) and assess the relationship between stool consistency and gastrointestinal symptoms. Methods Individuals with a physician diagnosis of IBS were recruited by advertisement. Enrollment questionnaires included the Rome III Diagnostic Questionnaire and IBS Symptom Severity Scale. Then 185 patients meeting Rome criteria for IBS rated the consistency (using the Bristol Stool Scale) of each bowel movement (BM) for 90 days and whether the BM was accompanied by pain, urgency, or soiling. Each night they transferred BM ratings from a paper diary to an internet form and also reported the average daily intensity of abdominal pain, bloating, bowel habit dissatisfaction, and life interference of bowel symptoms. Only the longest sequence of consecutive days of diary data was used in analysis (average of 73 days). Results Patients were 89% female with average age 36.6 years. 78% had both loose/watery and hard/lumpy stools; the average was 3 fluctuations between these extremes per month. The proportion of loose/watery stools correlated r=.78 between the first and second months and the proportion of hard/lumpy stools correlated r=.85 between months. Loose/watery stools were associated with more BM-related pain, urgency, and soiling than hard/lumpy or normal stools; however, IBS-C patients had significantly more BM-unrelated abdominal pain, bloating, dissatisfaction with bowel habits, and life interference than IBS-D. Questionnaires overestimated the frequency of abnormal stool consistency and gastrointestinal symptoms compared to diaries. Conclusions Stool consistency varies greatly within individuals. However, stool patterns are stable within an individual from month to month. The paradoxical findings of greater symptom severity after individual loose/watery BMs vs. greater overall symptom severity in IBS-C implies different physiological mechanisms for symptoms in constipation compared to diarrhea. Daily symptom monitoring is more sensitive and reliable than a questionnaire.

Update on Rome IV Criteria for Colorectal Disorders: Implications for Clinical Practice

“…Several recent studies have highlighted the substantial overlap between various functional bowel disorders, as well as substantial flux between these disorders and between the IBS subtypes [9–11, 12••, 13, 14, 15••]. Therefore, in Rome IV it is emphasized that functional bowel disorders constitute a spectrum of GI disorders rather than isolated entities.…”

“…However, studies using stool diaries with the proposed cut-off for defining the subgroups (25% hard and/or loose stools according to BSF) resulted in a very large proportion of subjects being defined as IBS-U, and a very small proportion fulfilled criteria for IBS-M [22–24], since IBS patients frequently have days with bowel movements with normal stool consistency (BSF3-5) [12••, 17]. Moreover, when using the proposed cut-off retrospectively in diagnostic questionnaires (“sometimes hard and/or loose stools”), an exceedingly high proportion instead were categorized as IBS-M [25].…”

Prediction of Delayed Colonic Transit Using Bristol Stool Form and Stool Frequency in Eastern Constipated Patients: A Difference From the West

“…There are a few plausible explanations on these findings. First, in IBS patients, stool consistency varies greatly within each individual, and bowel habits were also found to change overtime, 36,37 thus the reliability of the measurements of stool form and frequency in IBS patients come into question given this day-to-day variation. Second, colonic absorption and secretion may be different in patients with IBS compared to those without IBS.…”

Efficacy and mode of action of mesalazine in the treatment of diarrhoea-predominant irritable bowel syndrome (IBS-D): a multicentre, parallel-group, randomised placebo-controlled trial

“…We therefore modified the eligible criteria for IBS-D following registration with 'ClinicalTrials.gov' to reflect the fact that, as others have found, the bowel habit of patients with IBS-D is less abnormal than patients' reported symptoms suggest. 40 The patients were required to meet the modified Rome III criteria for IBS-D, 1 defined as a stool frequency of ≥ 3 per day for > 2 days per week and ≥ 25% of stools to be of types 5-7 [i.e. unlike standard Rome III criteria, 1 which state Bristol Stool Form Scale (BSFS) 6 and 7, to include stool form 5 as well] and < 25% of types 1 and 2 according to the BSFS.…”