Similarities in Clinical and Psychosocial Characteristics of Functional Diarrhea and Irritable Bowel Syndrome With Diarrhea

Prevalence and determinants of postprandial diarrhea in a tertiary care center

BACKGROUND AND AIMS

Postprandial diarrhea (PPD) is commonly seen in patients with disorders of gut-brain interaction (DGBI), but the factors associated with it have not been well studied. In this study, we aim to study the burden, impact, and predictors of PPD using a clinical cohort of DGBI patients.

METHODS

This study included patients with chronic diarrhea fulfilling ROME IV criteria for irritable bowel syndrome (IBS) or functional diarrhea (FDiarr). PPD was defined as patients reporting mushy/watery stools following meals ≥30% of the time in the last 3 months using a ROME IV question on PPD. Age, sex, and BMI, the severity of diarrhea, abdominal pain, depression, anxiety, somatization, and quality of life were assessed using validated measures. Person's chi-square test and Student's t-test were used to compare variables. A multiple linear regression model with backward elimination was done to determine predictors of PPD severity.

KEY RESULTS

Of 213 eligible patients, more than three-fourth of patients (75.6%) had PPD. Women (79.0%, p = 0.037), patients with ROME IV diagnosis of IBS-D (90.5%, p = 0.002), and functional dyspepsia (83.2%, p = 0.014), and those with a history of cholecystectomy (CCY) (95.5%, p = 0.022) were more likely to report PPD. PPD patients experienced more severe abdominal pain, diarrhea, and decreased quality of life (QoL) but showed no significant difference in BMI, anxiety, depression, sleep, or somatization. In our regression model, female sex and history of CCY were independent predictors of PPD.

CONCLUSIONS AND INFERENCES

PPD is frequently reported among chronic diarrhea patients and is associated with more severe GI symptoms and decreased QoL. Female sex and CCY predict PPD, while psychological factors do not.

What Is Unspecified Functional Bowel Disorder? A Commonly Seen, Rarely Recognized, and Poorly Understood Diagnosis

INTRODUCTION

Unspecified functional bowel disorder (FBD-U) is a Rome IV diagnosis of exclusion and occurs when patients report bowel symptoms but do not meet the criteria for other functional bowel disorders (FBD; irritable bowel syndrome [IBS], functional constipation [FC], functional diarrhea [FDr], or functional bloating). Previous research suggests that FBD-U is as/more common than IBS.

METHODS

One thousand five hundred one patients at a single-center tertiary care center completed an electronic survey. Study questionnaires included Rome IV Diagnostic Questionnaires, anxiety, depression, sleep, health care utilization, and bowel symptom severity measures.

RESULTS

Eight hundred thirteen patients met Rome IV criteria for a FBD and 194 patients (13.1%) met criteria for FBD-U, representing the second most common FBD after IBS. Severity of abdominal pain, constipation, and diarrhea were lower in FBD-U compared with other FBD, whereas health care utilization was similar among the groups. Scores on measures of anxiety, depression, and sleep disturbances were similar in FBD-U compared with FC and FDr but were less severe than IBS. Between 25% and 50% of patients with FBD-U did not meet Rome IV criteria for other FBD due to timing of onset of the target symptom (e.g., constipation for FC, diarrhea for FDr, and abdominal pain for IBS).

DISCUSSION

FBD-U, by Rome IV criteria, is highly prevalent in clinical settings. These patients are not represented in mechanistic studies or clinical trials for not having met Rome IV criteria for other FBD. Making future Rome criteria less stringent would minimize the number fulfilling criteria for FBD-U and maximize the true representation of FBD in clinical trials.

Irritable bowel syndrome - controversies in diagnosis and management

INTRODUCTION

The irritable bowel syndrome (IBS) is the best-recognized disorder of gut brain interactions (DGBI). However, it is controversial if the Rome IV criteria iteration for IBS diagnosis is fit for purpose.

AREAS COVERED

This review critically evaluates Rome IV criteria for diagnosis of IBS and addresses clinical considerations in IBS treatment and management, including dietary factors, biomarkers, disease mimics, symptom severity, and subtypes. The role of diet in IBS is critically reviewed along with the influence of the microbiota, including small intestinal bacterial overgrowth.

EXPERT OPINION

Emerging data suggest the Rome IV criteria are more suitable for identifying severe IBS and least useful for sub-diagnostic patients who are still likely to benefit from IBS treatment. Despite convincing evidence that IBS symptoms are diet-driven and often postprandial, a relationship to eating is not a Rome IV diagnostic criterion. Few IBS biomarkers have been identified, suggesting the syndrome is too heterogeneous to be measured by a single marker, and combined biomarker, clinical, dietary, and microbial profiling may be needed for objective characterization. With many organic diseases mimicking and overlapping with IBS, it's important clinicians are knowledgable about this to mitigate the risk of missing comorbid organic intestinal disease and to optimally treat IBS symptoms.

Differential Diagnosis of Chronic Diarrhea: An Algorithm to Distinguish Irritable Bowel Syndrome With Diarrhea From Other Organic Gastrointestinal Diseases, With Special Focus on Exocrine Pancreatic Insufficiency

Chronic diarrhea, defined as diarrhea persisting for more than 4 weeks, affects up to 5% of the population regardless of patient age, sex, race, or socioeconomic status. The impact on patient health and quality of life is substantial, and diagnosis and management of these patients have significant economic consequences for health care services. The differential diagnosis of chronic diarrhea is broad, with etiologies including infections, endocrinopathies, maldigestive/malabsorptive conditions, and disorders of gut-brain interaction. The considerable overlap of symptoms across this spectrum makes accurate diagnosis problematic and may lead to delays in diagnosis or misdiagnosis. In this narrative review, we consider the differential diagnosis of chronic diarrhea, focusing on irritable bowel syndrome with diarrhea and exocrine pancreatic insufficiency, two conditions that may present similarly but have very different underlying causes and require significantly different management strategies. We outline a 4-step diagnostic strategy and propose a straightforward algorithm to assist in efficiently differentiating irritable bowel syndrome from exocrine pancreatic insufficiency and other causes of chronic diarrhea. We anticipate that these aids will improve diagnostic accuracy, which ultimately should lead to improvements in patients' health-related quality of life and reduce the societal burden on health care services.

A Randomized, Double-Blind, Placebo-Controlled Trial to Evaluate the Effects of Multi-Strain Synbiotic in Patients with Functional Diarrhea and High Fecal Calprotectin Levels: A Pilot Study

Synbiotics, including probiotics and prebiotics, are useful for patients with functional bowel disorders. However, which synbiotics are beneficial for patients with which diseases, especially those with functional diarrhea (FDr) with high fecal calprotectin levels, is currently unknown. FDr is an extension of irritable bowel syndrome with diarrhea (IBS-D). Although fewer studies have been conducted on FDr compared to IBS-D, its importance is increasing as its prevalence increases. The aim of this study was to evaluate the effects of a synbiotic containing a mixture of Lactobacillus and Bifidobacterium and its substrate, fructooligosaccharide, on bowel symptoms, fecal calprotectin levels, fecal microbiota, and safety in FDr patients with high fecal calprotectin levels. Forty patients were randomly assigned to either a synbiotic group or a placebo group. A total of 20 subjects in the synbiotic group and 19 subjects in the placebo group completed the study (8 weeks). Changes in FDr symptoms, fecal calprotectin levels, and gut microbiota were assessed during the intervention period. At 4 and 8 weeks, the number of bowel movements tended to increase in the synbiotic group, with a significant increase in the number of formed stools rather than loose stools (p < 0.05). Bowel movement satisfaction was significantly increased in the synbiotic group, but not in the placebo group. Intestinal flora analysis revealed that Lactobacillales at the order level was increased only in the synbiotic group at the end of the intervention. In contrast, at week 8 of the intervention, log-transformed fecal calprotectin levels were significantly decreased in the synbiotic group, although the change was not significantly different from that of the placebo group. These findings suggest that the intake of a multi-strain-containing synbiotic for 8 weeks could improve gut symptoms and the intestinal microenvironment of FDr patients with high fecal calprotectin levels.

Fecal Microbiota Transplantation Could Improve Chronic Diarrhea in Cynomolgus Monkey by Alleviating Inflammation and Modulating Gut Microbiota

Chronic diarrhea is associated with enteric dysbiosis and provokes the overuse of antibiotics. Fecal microbiota transplantation (FMT) is a promising therapy, but it shows discrepant clinical efficacy. Bacterial colonization in recipients has been studied, although little is known about the role of gut fungi and Archaea after FMT. In this study, we evaluated the efficacy of human-derived FMT on spontaneous chronic diarrhea cynomolgus monkeys and revealed the effector mechanisms. We demonstrated that FMT can mitigate the appearance of diarrheal symptoms and inhibit the increase in interleukin-6, interleukin-8, interleukin-1β, and interferon-γ and the decrease in interleukin-10 in serum. We confirmed that FMT restored the disturbance of gut bacteria by reducing the relative abundances of potential pathogens, including Cloacibacillus porcorum, Desulfovibrio desulfuricans, Erysipelotrichaceae bacterium 5_2_54FAA, and Erysipelotrichaceae bacterium 21_3, and increasing the levels of Lactobacillus fermentum and Lactobacillus ruminis CAG_367 in diarrheal monkeys. The metabolic pathways of healthy and FMT monkeys' gut bacteria were enriched in amino acid metabolism, carbohydrate metabolism, and lipid metabolism, while the metabolic pathways of pre-FMT monkeys' gut bacteria were enriched in antibiotic production. Moreover, a higher Ascomycota/Basidiomycota ratio, higher Aspergillus levels, and lower Trichosporon asahii abundance were present in intestinal fungi after FMT. Although the abundance of the Archaea Methanosphaera stastmanae did not change significantly, it was inversely correlated with the anti-inflammatory factor IL-4 after FMT. These results support the further development and application of FMT for chronic diarrhea.

Current and Future Therapeutic Options for Irritable Bowel Syndrome with Diarrhea and Functional Diarrhea

Irritable bowel syndrome with diarrhea and functional diarrhea are disorders of gut-brain interaction presenting with chronic diarrhea; they have significant impact on quality of life. The two conditions may exist as a continuum and their treatment may overlap. Response to first-line therapy with antispasmodics and anti-diarrheal agents is variable, leaving several patients with suboptimal symptom control and need for alternative therapeutic options. Our aim was to discuss current pharmacologic options and explore alternative therapeutic approaches and future perspectives for symptom management in irritable bowel syndrome with diarrhea and functional diarrhea. We conducted a search of PubMed, Cochrane, clinicaltrial.gov, major meeting abstracts for publications on current, alternative, and emerging drugs for irritable bowel syndrome with diarrhea and functional diarrhea. Currently approved therapeutic options for patients with first-line refractory irritable bowel syndrome with diarrhea and functional diarrhea include serotonin-3 receptor antagonists, eluxadoline and rifaximin. Despite their proven efficacy, cost and availability worldwide impact their utilization. One-third of patients with disorders of gut-brain interaction with diarrhea have bile acid diarrhea and may benefit from drugs targeting bile acid synthesis and excretion. Further understanding of underlying pathophysiology of irritable bowel syndrome with diarrhea and functional diarrhea related to bile acid metabolism, gastrointestinal transit, and microbiome has led to evaluation of novel therapeutic approaches, including fecal microbiota transplantation and enterobacterial "crapsules". These opportunities to treat disorders of gut-brain interaction with diarrhea should be followed with formal studies utilizing large samples of well-characterized patients at baseline and validated response outcomes as endpoints for regulatory approval.

Abdominal Pain Severity Is Mainly Associated with Bloating Severity in Patients with Functional Bowel Disorders and Functional Abdominal Pain

PURPOSE

Abdominal pain is a cardinal sign of functional bowel disorders (FBD), in favor of irritable bowel syndrome (IBS). However, the determinants of abdominal pain severity (APS) are unknown. The present study aimed to search the relationships between APS and demographic, psychological, and clinical parameters in tertiary care FBD outpatients.

PATIENTS AND METHODS

In this retrospective study, we included 2043 new outpatients with FBD or functional abdominal pain. They fulfilled the Rome III questionnaire, psychological evaluation, and four 10-points Likert scale for the perceived severity of constipation, diarrhea, bloating, and abdominal pain. Linear regression was performed for each phenotype to model the severity of abdominal pain with demographic, psychological parameters, and symptoms severity.

RESULTS

APS was positively associated with bloating severity in all phenotypes, but APS was also associated with other variables according to gender and phenotype. APS was negatively associated with age and positively with depression, constipation severity, and diarrhea severity in female patients. In male patients, APS was associated with state anxiety, constipation severity, and diarrhea severity. APS severity was associated with bloating severity and transit severity in IBS patients, while in non-IBS patients, APS was only associated with bloating severity.

CONCLUSION

Perceived abdominal pain severity is always associated with perceived bloating severity in FBD and FAP patients.

Functional bowel disorders with diarrhoea: Clinical guidelines of the United European Gastroenterology and European Society for Neurogastroenterology and Motility

Irritable bowel syndrome with diarrhoea (IBS‐D) and functional diarrhoea (FDr) are the two major functional bowel disorders characterized by diarrhoea. In spite of their high prevalence, IBS‐D and FDr are associated with major uncertainties, especially regarding their optimal diagnostic work‐up and management. A Delphi consensus was performed with experts from 10 European countries who conducted a literature summary and voting process on 31 statements. Quality of evidence was evaluated using the grading of recommendations, assessment, development, and evaluation criteria. Consensus (defined as >80% agreement) was reached for all the statements. The panel agreed with the potential overlapping of IBS‐D and FDr. In terms of diagnosis, the consensus supports a symptom‐based approach also with the exclusion of alarm symptoms, recommending the evaluation of full blood count, C‐reactive protein, serology for coeliac disease, and faecal calprotectin, and consideration of diagnosing bile acid diarrhoea. Colonoscopy with random biopsies in both the right and left colon is recommended in patients older than 50 years and in presence of alarm features. Regarding treatment, a strong consensus was achieved for the use of a diet low fermentable oligo‐, di‐, monosaccharides and polyols, gut‐directed psychological therapies, rifaximin, loperamide, and eluxadoline. A weak or conditional recommendation was achieved for antispasmodics, probiotics, tryciclic antidepressants, bile acid sequestrants, 5‐hydroxytryptamine‐3 antagonists (i.e. alosetron, ondansetron, or ramosetron). A multinational group of European experts summarized the current state of consensus on the definition, diagnosis, and management of IBS‐D and FDr.

Improvement in constipation and diarrhea is associated with improved abdominal pain in patients with functional bowel disorders

BACKGROUND

Abdominal pain is a bothersome and lifestyle limiting symptom in patients with functional bowel disorders. It is associated with decreased quality of life in affected individuals, as well as significant annual healthcare expenditure. Knowledge of specific factors that predict improvement in abdominal pain in those with functional bowel disorders is thus far limited.

METHODS

Consecutive patients presenting for outpatient care at a major academic medical center between October 2017 and March 2020 completed an electronic symptom survey prior to initial clinic visit, and again after 3 months. The Rome IV questionnaires for functional dyspepsia, irritable bowel syndrome, functional constipation, and functional diarrhea were all included. Additionally, all subjects completed the Patient Reported Outcomes Measurement Information System Anxiety, Depression, and sleep disturbance questionnaires. Patients with a diagnosis of a Rome IV functional gastrointestinal disorder without any organic cause for symptoms were identified based on both chart review as well as survey response data. Univariable and multivariable analysis was used to assess predictors of improved abdominal pain after 3 months.

KEY RESULTS

180 patients with a mean age of 45.3 years were included in the final analysis. 78.3% of patients were female, and 77.2% met Rome IV criteria for irritable bowel syndrome. On multivariable analysis, improvement in constipation and diarrhea were both independent predictors of improved abdominal pain after 3 months.

CONCLUSIONS AND INFERENCES

Improvement in constipation and diarrhea both predicted improvement in abdominal pain, suggesting that addressing these factors is central to the management of abdominal pain in functional gastrointestinal disorders.

Role of psychological questionnaires in clinical practice and research within functional gastrointestinal disorders

Functional gastrointestinal (GI) disorders, also known as disorders of gut-brain interaction (DGBI), affect 40% of the global population. Up to two-thirds of patients with FGIDs experience a major psychological disorder making a thorough psychosocial assessment a critical part of patient care as it can impact treatment approach. Many psychological questionnaires exist in the clinical realm serving different purposes including screening for anxiety and depression, somatization symptoms, health-related anxiety, illness impact, and health-related quality of life. Given the abundance of questionnaires used to screen for similar psychiatric comorbidities, correlation between different instruments is needed to allow for pooling of data. In this issue of Neurogastroenterology & Motility, Snijkers et al. conducted the first comparative study to assess the correlation between the Hospital Anxiety and Depression Scale (HADS) and the Patient Health Questionnaire-9 (PHQ-9) and Generalized Anxiety Disorder-7 (GAD-7) to determine optimal cutoffs for diagnosis of depressive and anxiety disorders in a cohort of irritable bowel syndrome patients. The biopsychosocial framework as it applies to FGID has led to the inclusion of both psychosocial assessments in clinical management and research protocols. Future directions include the development of symptom-specific questionnaires for groups of FGIDs, culturally specific psychosocial questionnaires, and inclusion of psychosocial well-being as primary or secondary outcomes in clinical research trials. In this review, we aim to explore the role of psychological questionnaires in clinical care and research trials and share practical tips on incorporating a biopsychosocial framework in the care of patients with FGIDs.

Increased psychological distress and somatization in patients with irritable bowel syndrome compared with functional diarrhea or functional constipation, based on Rome IV criteria

BACKGROUND

The Rome IV criteria for disorders of gut-brain interaction define irritable bowel syndrome (IBS) as a functional bowel disorder associated with frequent abdominal pain of at least 1 day per week. In contrast, functional diarrhea (FD) and functional constipation (FC) are relatively painless. We compared differences in mood and somatization between Rome IV IBS and FC/FD.

METHODS

A total of 567 patients with Rome IV defined IBS or FD/FC completed a baseline questionnaire on demographics, abdominal pain frequency, mood (hospital anxiety and depression scale, HADS), and somatization (patient health questionnaire, PHQ-12). The primary analysis compared differences in mood and somatization between IBS and FC/FD, and the relative influence of abdominal pain frequency on these extra-intestinal symptoms. The secondary analysis evaluated differences across individual IBS subtypes, and also between FC and FD.

KEY RESULTS

Patients with IBS-in comparison to those with FC/FD-had significantly higher mean PHQ-12 somatization scores (9.1 vs. 5.4), more somatic symptoms (6.0 vs. 4.3), abnormally high somatization levels (16% vs. 3%), higher HADS score (15.0 vs. 11.7), and clinically abnormal levels of anxiety (38% vs. 20%) and depression (17% vs. 10%). Increasing abdominal pain frequency correlated positively with PHQ-12, number of somatic symptoms, and HADS; p < 0.001. No differences in mood and somatization scores were seen between individual IBS subtypes, and nor between FC and FD.

CONCLUSION & INFERENCES

Based on the Rome IV criteria, IBS is associated with increased levels of psychological distress and somatization compared with FD or FC. Patients reporting frequent abdominal pain should be comprehensively screened for psychosomatic disorders, with psychological therapies considered early in the disease course.

Diagnosis and Treatment of Irritable Bowel Syndrome: A Review

IMPORTANCE

The prevalence of irritable bowel syndrome (IBS) in the United States is between 7% and 16%, most common in women and young people, with annual direct costs estimated at more than $1 billion dollars in the United States. Traditionally, the diagnosis of IBS has been based on the positive identification of symptoms that correlate with several different syndromes associated with disorders such as IBS diarrhea, IBS constipation, functional diarrhea, functional constipation, chronic functional abdominal pain, or bloating. Several peripheral and central mechanisms initiate gastrointestinal motor and sensory dysfunctions leading to IBS symptoms. Those dysfunctions may require evaluation in patients whose symptoms do not respond to first-line treatments.

OBSERVATIONS

Validation studies of consensus symptom-based criteria have identified deficiencies that favor a simpler identification of the predominant symptoms of abdominal pain, bowel dysfunction, and bloating and exclusion of alarm symptoms such as unintentional weight loss, rectal bleeding, or recent change in bowel function. Symptom-based diagnosis of IBS is enhanced with additional history for symptoms of somatoform and psychological disorders and alarm symptoms, physical examination including digital rectal examination, and screening tests to exclude organic disease (by measuring hemoglobin and C-reactive protein concentrations). The initial treatment plan should include patient education, reassurance, and first-line treatments such as fiber and osmotic laxatives for constipation, opioids for diarrhea, antispasmodics for pain and for management of associated psychological disorders. For patients who do not respond to those IBS treatments, testing for specific functional disorders may be required in a minority of patients with IBS. These disorders include rectal evacuation disorder, abnormal colonic transit, and bile acid diarrhea. Their identification is followed by individualized treatment, such as pelvic floor retraining for rectal evacuation disorders, sequestrants for bile acid diarrhea, and secretory agents for constipation, although there is only limited evidence that this individualized management approach is effective.

CONCLUSIONS AND RELEVANCE

Advances in the identification of specific dysfunctions as causes of individual symptoms in the "IBS spectrum" leads to the potential to enhance the diagnosis and management of symptoms for the majority of patients for whom first-line therapies of IBS and management of comorbid psychological disorders are insufficient.

Shenling Baizhu Powder () Ameliorates Pi (Spleen)-Deficiency-Induced Functional Diarrhea in Rats

OBJECTIVE

To explore the mechanism of Pi (Spleen)-deficiency-induced functional diarrhea (FD) model rats treated by Shenling Baizhu Powder (, SBP).

METHODS

Thirty male Sprague-Dawley rats were randomly divided into 5 groups including control, model, low-, medium-, and high-dose SBP groups (SBPLDG, SBPMDG, SBPHDG), 6 rats in each group, respectively. Pi-deficiency-induced FD rats model was developed through Radix et Rhizoma Rhei gavage for 7 days. After modeling, the rats were treated with 3 doses of SBP [0.93, 1.86, and 3.72 g/(kg·d)], and the rats in the control and model groups were given pure water for 7 days. The diarrhea index was calculated. On the 7th and 14th days, the traveled distance of rat was measured by the open field test. Serum D-xylose content was determined by the phloroglucinol method and interleukin (IL)-10 and IL-17 levels were measured using an enzyme-linked immunosorbent assay kit. The content of Treg cells was determined by flow cytometry.

RESULTS

Compared with the control group, the diarrhea index and IL-17 level in the model group were significantly higher and the total exercise distance and D-xylose content significantly decreased (P>0.05). The expression of IL-10 in the SBPHDG group was significantly up-regulated, and serum D-xylose level and Treg cells increased significantly compared with the model group (P>0.05).

CONCLUSION

High-dose SBP exhibited ameliorating effects against Pi-deficiency induced FD, which might be attributed to its modulations on intestinal absorption function as well as adaptive immunity in mesenteric lymph nodes of rat.

Irritable Bowel Syndrome: Straightening the road from the Rome criteria

A sequence of consensus-based Rome criteria for irritable bowel syndrome (IBS) has been published since 1989. The fundamental definition based on abdominal pain in association with bowel dysfunction has been consistent. However, two major changes occurred in the Rome II and IV criteria. The former change involved "splitting off" of symptoms that were not consistently associated with pain, such as functional, constipation, diarrhea, and bloating. In Rome IV, the main changes were the exclusion of discomfort (in contrast to pain) and the more stringent frequency criteria for the pain to be eligible for diagnosis of IBS (specifically, on average, at least 1 day per week in the last 3 months). Validation studies of the consensus, symptom-based criteria have identified multiple deficiencies that question the rationale for "splitting" the different syndromes, and favor a simpler identification of the classical symptoms of abdominal pain, bowel dysfunction, and bloating, and exclusion of alarm symptoms. Advances in the identification of actionable biomarkers related to the symptoms suggestive of functional gastrointestinal disorders have the potential to usher a change in practice from positive diagnosis of symptom complexes followed by empirical treatment to identification of the mechanisms causing the symptoms and targeted therapy.