Canadian Association of Gastroenterology Clinical Practice Guideline on the Management of Bile Acid Diarrhea

Bile acid diarrhea in patients with chronic diarrhea. Current appraisal and recommendations for clinical practice

Bile Acid Diarrhea (BAD) is a common cause of chronic diarrhea, often accompanied by urgency, occasional fecal incontinence, abdominal pain, and fatigue. A nationwide survey has shown limited awareness of BAD within the Italian medical community, prompting a panel of experts to develop a Position Paper that outlines the most practical and cost-saving diagnostic investigations and treatments for this frequently overlooked condition. The document provides an overview of the epidemiology, pathophysiology, clinical manifestations, and classification of the different types of Bile Acid Diarrhea (BAD). A key focus is the diagnostic approach to identifying and managing the many undiagnosed BAD patients in both primary care and specialized medical settings. Finally, the paper addresses the optimal therapeutic strategies for BAD, including traditional bile acid sequestrants and newer, promising treatments.

Advances in the pathophysiology, diagnosis and management of chronic diarrhoea from bile acid malabsorption: a systematic review

Bile acid malabsorption (BAM) is an important disorder of digestive pathophysiology as it generates chronic diarrhoea. This condition originates from intricate pathways involving bile acid synthesis and metabolism in the liver and gut, the composition of gut microbiota, enterohepatic circulation and key receptors as farnesoid X receptor (FXR), fibroblast growth factor receptor 4 (FGFR4), and the G-protein bile acid receptor-1 (GPBAR-1). Although symptoms can resemble those related to disorders of gut brain interaction, accurate diagnosis of BAM may greatly benefit the patient. The empiric diagnosis of BAM is primarily based on the clinical response to bile acid sequestrants. Specific tests including the 48-hour fecal bile acid test, serum levels of 7α-hydroxy-4-cholesten-3-one (C4) and fibroblast growth factor 19 (FGF19), and the 75Selenium HomotauroCholic Acid Test (SeHCAT) are not widely available. Nevertheless, lack of diagnostic standardization of BAM may account for poor recognition and delayed management. Beyond bile acid sequestrants, therapeutic approaches include the use of FXR agonists, FGF19 analogues, glucagon-like peptide-1 (GLP-1) receptor agonists, and microbiota modulation. These novel agents can best make their foray into the therapeutic armamentarium if BAM does not remain a diagnosis of exclusion. Ignoring BAM as a specific condition may continue to contribute to increased healthcare costs and reduced quality of life. Here, we aim to provide a comprehensive review of the pathophysiology, diagnosis, and management of BAM.

Managing bile acid diarrhea: aspects of contention

INTRODUCTION

Bile acid diarrhea is a common cause of bowel symptoms and often goes unrecognized or misdiagnosed. Many aspects of management remain contentious.

AREAS COVERED

The primary, idiopathic condition should be suspected in people with functional diarrhea or diarrhea-predominant irritable bowel syndrome. Secondary causes include ileal resection, inflammation, and post-cholecystectomy. Diagnostic tests vary globally, being unavailable in many countries, and further refinement of testing strategy is needed. Management is usually long-term symptom control, rather than reversal of the causative factors, which are still being defined. Bile acid sequestrants remain the main drugs used. They are relatively inexpensive, and better-quality data is now available for colesevelam. However, optimal use, including timing and formulation, needs clarification. The GLP-1 receptor agonist, liraglutide, is also effective, although mechanisms of action and whether this effect is common to other class members is unclear. They are more expensive, and availability varies. FXR agonists can also be effective but require further validation. The role of dietary factors in symptom development is a major patient concern, needing more formal studies.

EXPERT OPINION

To build on recent findings, bile acid diarrhea needs further investment into causes, diagnosis and therapy to guide present and future patient care.

Diet management in congenital diarrheas and enteropathies - general concepts and disease-specific approach, a narrative review

Congenital diarrheas and enteropathies (CODE) are a group of rare, heterogenous, monogenic disorders that lead to chronic diarrhea in infancy. Definitive treatment is rarely available, and supportive treatment is the mainstay. Nutritional management in the form of either specialized formulas, restrictive diet, or parenteral nutrition support in CODE with poor enteral tolerance is the cornerstone of CODE treatment and long-term growth. The evidence to support the use of specific diet regimens and nutritional approaches in most CODE disorders is limited due to the rarity of these diseases and the scant published clinical experience. The goal of this review was to create a comprehensive guide for nutritional management in CODE, based on the currently available literature, disease mechanism, and the PediCODE group experience. Enteral diet management in CODE can be divided into 3 distinct conceptual frameworks: nutrient elimination, nutrient supplementation, and generalized nutrient restriction. Response to nutrient elimination or supplementation can lead to resolution or significant improvement in the chronic diarrhea of CODE and resumption of normal growth. This pattern can be seen in CODE due to carbohydrate malabsorption, defects in fat absorption, and occasionally in electrolyte transport defects. In contrast, general diet restriction is mainly supportive. However, occasionally it allows parenteral nutrition weaning or reduction over time, mainly in enteroendocrine defects and rarely in epithelial trafficking and polarity defects. Further research is required to better elucidate the role of diet in the treatment of CODE and the appropriate diet management for each disease.

At an appointment with a patient with diarrhea: the doctor’s algorithm of actions

Diarrhoea is one of the most common gastroenterological complaints made by patients who seek medical attention. It can be a manifestation of the whole range of different diseases, although not exclusively of the digestive tract, which requires a thorough examination of the patient and often is a challenge for the clinician, especially in the limited time settings during an outpatient visit. The cause of diarrhoea should be identified early to begin treatment of the patient in a timely and rational manner. In managing a patient with diarrhoea, a diagnostic search must begin with the following actions: working out complaints in detail, identification of symptoms of anxiety and taking a medical history, including epidemiological, pharmaceutical, hereditary, allergic, as well as analysis of dietary preferences. A physical examination is an integral part of the patient management; it allows to assess the general health condition, identify signs of dehydration and clinical stigmas of the underlying condition, which may manifest itself as diarrhoea. After an initial examination and exclusion of anxiety symptoms, a number of laboratory and instrumental examination methods is prescribed to determine the cause of diarrhoea. Given the polyetiology of diarrhoea syndrome, the range of methods for examining the patient can be quite wide, therefore the choice of area for the diagnostic search and the scope of the necessary diagnostic procedures is carried out on an individual basis, taking into account the features of the clinical picture, history data and physical examination findings. Treatment of a patient with diarrhoea at the pre-examination stage must include rehydration, timely detection and correction of electrolyte disturbances and other possible complications. Once the cause of diarrhoea has been established, the patient is treated due to the identified etiological factor in accordance with the current clinical guidelines. The article presents a step-by-step algorithm for making a differential diagnosis in a patient with diarrhoea, and also presents our own clinical observations.

Efficacy and safety of Chinese herbal medicine in treating postcholecystectomy diarrhea: A systematic review and meta-analysis

BACKGROUND

Postcholecystectomy diarrhea (PCD) is among the most distressing and well-known clinical complications of cholecystectomy. Despite various available treatment options, clinical outcomes are greatly limited by unclear pathophysiological mechanisms. Chinese herbal medicine (CHM) is widely used as a complementary and alternative therapy for the treatment of functional diarrhea. Thus, we conducted a meta-analysis of randomized controlled trials (RCTs) to evaluate the efficacy and safety of CHM for the treatment of PCD.

METHODS

Electronic database searches were conducted using the Cochrane Library, PubMed, Web of Science, Embase, Wanfang Data, China National Knowledge Infrastructure, and the Chinese Scientific Journal Database. All RCTs on CHMs for managing patients with PCD were included. The meta-analysis was performed using RevMan 5.4 software.

RESULTS

The present meta-analysis included 14 RCTs published between 2009 and 2021 in China. The primary findings indicated that CHM had a higher total efficacy and cure rate as a monotherapy for PCD (P < .00001). Two trials reported the scores of the main symptoms with statistically significant differences in stool nature (P < .00001), defecation frequency (P = .002), and abdominal pain and bloating (P < .00001). In addition, CHM reduced CD3+ and CD4+ levels more effectively in terms of T lymphocyte subset determination (P < .00001). The main symptoms of PCD in traditional Chinese medicine (TCM) are splenic deficiency and liver stagnation. All treatments were used to strengthen the spleen and (or) soothing the liver.

CONCLUSION

CHM had a favorable effect on PCD. No adverse events were observed. Larger, high-quality RCTs are warranted to draw definitive conclusions and standardize treatment protocols.

Clinical practice guidelines for prevention and treatment of postoperative gastrointestinal disorder with Integrated Traditional Chinese and Western Medicine (2023)

Postoperative gastrointestinal disorder (POGD) was a common complication after surgery under anesthesia. Strategies in combination with Traditional Chinese Medicine and Western medicine showed some distinct effects but standardized clinical practice guidelines were not available. Thus, a multidisciplinary expert team from various professional bodies including the Perioperative and Anesthesia Professional Committees of the Chinese Association of Integrative Medicine (CAIM), jointly with Gansu Province Clinical Research Center of Integrative Anesthesiology/Anesthesia and Pain Medical Center of Gansu Provincial Hospital of Traditional Chinese Medicine and WHO Collaborating Center for Guideline Implementation and Knowledge Translation/Chinese Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) Center/Gansu Provincial Center for Medical Guideline Industry Technology/Evidence-based Medicine Center of Lanzhou University, was established to develop evidence-based guidelines. Clinical questions (7 background and 12 clinical questions) were identified through literature reviews and expert consensus meetings. Based on systematic reviews/meta-analyses, evidence quality was analyzed and the advantages and disadvantages of interventional measures were weighed with input from patients' preferences. Finally, 20 recommendations were developed through the Delphi-based consensus meetings. These recommendations included disease definitions, etiologies, pathogenesis, syndrome differentiation, diagnosis, and perioperative prevention and treatment.

Journal of Clinical Gastroenterology Lectureship Dubai 2022 : Management of Irritable Bowel Syndrome With Diarrhea

Irritable bowel syndrome (IBS) with diarrhea (IBS-D) affects ~1% of the general population and is characterized by abdominal pain associated with diarrhea. IBS-D symptoms significantly impact the quality of life of patients. Major uncertainties remain regarding the optimal management of these patients. Several therapies have been investigated over the years for the treatment of IBS-D. In the initial management, commonly prescribed approaches with an effect on global IBS symptoms include a low Fermentable Oligo-, Di-, Mono-Saccharides and Polyols diet and probiotics, while antispasmodics are used for targeting abdominal pain and loperamide for diarrhea only. Additional therapeutic options for the relief of global IBS symptoms include rifaximin, 5-HT 3 antagonists, gut-directed psychological therapies, and eluxadoline, while tricyclic antidepressants can target abdominal pain and bile acid sequestrants diarrhea. Promising evidence exists for the use of mesalazine and fecal microbiota transplantation in IBS-D, although further evidence is needed for definitive conclusions regarding their efficacy.

Food intolerance related to gastrointestinal symptoms amongst adults living with bile acid diarrhoea: A cross-sectional study

BACKGROUND

The role of food in managing bile acid diarrhoea (BAD) is poorly understood. The present study explored the prevalence of food intolerance amongst adults with BAD.

METHODS

The study comprised a cross-sectional survey of adults with BAD determined by the 75 selenium homotaurocholic acid test (SeHCAT) living in the UK. Participants anonymously completed an online questionnaire on 39 food items. Frequency of food in general affecting BAD symptoms, as well as frequencies of diarrhoea, abdominal pain, bloating, flatulence and consequential food avoidance after food item ingestion, were assessed. Food group avoidance was also assessed.

RESULTS

There were 434 participants who completed the questionnaire between April and May 2021 of whom 80% reported moderate to severe chronic diarrhoea. Food intolerances were reported by 88.0% (95% confidence interval [CI] = 84.6-90.9) of participants. Diarrhoea was reported most frequently after take-away food, fish and chips, creamy sauces, cream and large quantities of fruit (range 41.0%-33.6%). Lowest frequencies were for potato, avocado, mango, watermelon and pear (range 3.7%-7.4%) for the foods listed in the questionnaire. Similar trends were found for abdominal pain, bloating, flatulence and consequential food avoidance. Symptom-triggering within 30 min of ingestion was more prevalence than after 30 min for almost all foods. Food group avoidance was highest for fatty foods (81.2%; 95% CI = 77.8-85.3) followed by dairy (53.9%; 95% CI = 49.1-58.7).

CONCLUSIONS

Perceived food intolerance amongst adults with BAD and persisting diarrhoeal symptoms is high. Important triggers were meals with a higher fat content and higher-fat dairy products. Diets amongst those with persisting diarrhoeal symptoms may be overly restrictive.

Bile Acid Diarrhea: From Molecular Mechanisms to Clinical Diagnosis and Treatment in the Era of Precision Medicine

Bile acid diarrhea (BAD) is a multifaceted intestinal disorder involving intricate molecular mechanisms, including farnesoid X receptor (FXR), fibroblast growth factor receptor 4 (FGFR4), and Takeda G protein-coupled receptor 5 (TGR5). Current diagnostic methods encompass bile acid sequestrants (BAS), 48-h fecal bile acid tests, serum 7α-hydroxy-4-cholesten-3-one (C4), fibroblast growth factor 19 (FGF19) testing, and 75Selenium HomotauroCholic acid test (75SeHCAT). Treatment primarily involves BAS and FXR agonists. However, due to the limited sensitivity and specificity of current diagnostic methods, as well as suboptimal treatment efficacy and the presence of side effects, there is an urgent need to establish new diagnostic and treatment methods. While prior literature has summarized various diagnostic and treatment methods and the pathogenesis of BAD, no previous work has linked the two. This review offers a molecular perspective on the clinical diagnosis and treatment of BAD, with a focus on FXR, FGFR4, and TGR5, emphasizing the potential for identifying additional molecular mechanisms as treatment targets and bridging the gap between diagnostic and treatment methods and molecular mechanisms for a novel approach to the clinical management of BAD.

Prospective comparison of diagnostic tests for bile acid diarrhoea

BACKGROUND

Bile acid diarrhoea is often missed because gold standard nuclear medicine tauroselcholic [75-Se] acid (SeHCAT) testing has limited availability. Empirical treatment effect has unknown diagnostic performance, whereas plasma 7α-hydroxy-4-cholesten-3-one (C4) is inexpensive but lacks sensitivity.

AIMS

To determine diagnostic characteristics of empirical treatment and explore improvements in diagnostics with potential better availability than SeHCAT.

METHODS

This diagnostic accuracy study was part of a randomised, placebo-controlled trial of colesevelam. Consecutive patients with chronic diarrhoea attending SeHCAT had blood and stool sampled. Key thresholds were C4 > 46 ng/mL and SeHCAT retention ≤10%. A questionnaire recorded patient-reported empirical treatment effect. We analysed receiver operating characteristics and explored machine learning applied logistic regression and decision tree modelling with internal validation.

RESULTS

Ninety-six (38%) of 251 patients had SeHCAT retention ≤10%. The effect of empirical treatment assessed with test results for bile acid studies blinded had 63% (95% confidence interval 44%-79%) sensitivity and 65% (47%-80%) specificity; C4 > 46 ng/mL had 47% (37%-57%) and 92% (87%-96%), respectively. A decision tree combining C4 ≥ 31 ng/mL with ≥1.1 daily watery stools (Bristol type 6 and 7) had 70% (51%-85%) sensitivity and 95% (83%-99%) specificity. The logistic regression model, including C4, the sum of measured stool bile acids and daily watery stools, had 77% (58%-90%) sensitivity and 93% (80%-98%) specificity.

CONCLUSIONS

Diagnosis of bile acid diarrhoea using empirical treatment was inadequate. Exploration suggested considerable improvements in the sensitivity of C4-based testing, offering potential widely available diagnostics. Further validation is warranted.

CLINICALTRIALS

gov: NCT03876717.

Diagnosis and treatment of post-cholecystectomy diarrhoea

The incidence of cholecystitis is relatively high in developed countries and may usually be attributed to gallstones, the treatment for which involves complete surgical removal of the gallbladder (cholecystectomy). Bile acids produced following cholecystectomy continue to flow into the duodenum but are poorly absorbed by the colon. Excessive bile acids in the colon stimulate mucosal secretion of water and electrolytes leading, in severe cases, to diarrhoea. Bile acid diarrhoea (BAD) is difficult to diagnose, requiring a comprehensive medical history and physical examination in combination with laboratory evaluation. The current work reviews the diagnosis and treatment of BAD following cholecystectomy.

Persistent and new-onset symptoms after cholecystectomy in patients with uncomplicated symptomatic cholecystolithiasis: A post hoc analysis of 2 prospective clinical trials

BACKGROUND

Laparoscopic cholecystectomy is the gold standard for treating biliary colic in patients with gallstones, but post-cholecystectomy abdominal pain is commonly reported. This study investigates which symptoms are likely to persist and which may develop after a cholecystectomy.

METHODS

Patients from 2 previous prospective trials who underwent laparoscopic cholecystectomy for symptomatic cholecystolithiasis were included. Patients completed questionnaires on pain and gastrointestinal symptoms before surgery and at 6 months follow-up. The prevalence of persistent and new-onset abdominal symptoms was evaluated.

RESULTS

A total of 820 patients received cholecystectomy and were included, 75.4% female (n = 616/820) mean age 49.4 years (standard deviation 13.7). At baseline, 74.1% (n = 608/820) of patients met all criteria for biliary colic. Cholecystectomy successfully resolved biliary colic in 94.8% (n = 327/345) of patients, but 36.5% (n = 299/820) of patients reported persistent abdominal pain after 6 months of follow-up. The prevalence of most abdominal symptoms reduced significantly. Symptoms such as flatulence (17.8%, n = 146/820) or restricted eating (14.5%, n = 119/820) persisted most often. New-onset symptoms were frequent bowel movements (9.6%, n = 79/820), bowel urgency (8.5%, n = 70/820), and new-onset diarrhea (8.4%, 69/820).

CONCLUSION

Postcholecystectomy symptoms are mainly flatulence, frequent bowel movements, and restricted eating. Newly reported symptoms are mainly frequent bowel movements, bowel urgency, and diarrhea. The present findings give clinical guidance in informing, managing, and treating patients with symptoms after cholecystectomy.

Misinterpreting Diarrhea-Predominant Irritable Bowel Syndrome and Functional Diarrhea: Pathophysiological Highlights

Irritable bowel syndrome with predominant diarrhea (IBS-D) and functional diarrhea (FD) are disorders of gut-brain interaction characterized by recurring symptoms which have a serious impact on the patient's quality of life. Their pathophysiology is far from being completely understood. In IBS-D growing evidence suggests that bile acid malabsorption (BAM) could be present in up to 30% of patients. Microscopic colitis (MC) is a well-known cause of watery diarrhea and some patients, at first, can be diagnosed as IBS-D or FD. Both BAM and MC are often responsible for the lack of response to conventional treatments in patients labelled as "refractory". Moreover, because BAM and MC are not mutually exclusive, and can be found in the same patient, they should always be considered in the diagnostic workout when a specific treatment for BAM or MC is unsatisfactory. In the present review the possible shared pathogenetic mechanisms between BAM and MC are discussed highlighting how MC can induce a secondary BAM. Moreover, a brief overview of the current literature regarding the prevalence of their association is provided.

Efficacy and safety of colesevelam for the treatment of bile acid diarrhoea: a double-blind, randomised, placebo-controlled, phase 4 clinical trial

BACKGROUND

Bile acid diarrhoea is a common but overlooked cause of chronic watery diarrhoea. Plasma 7α-hydroxy-4-cholesten-3-one (C4) is an alternative to the gold standard tauroselcholic [⁷⁵Se] acid (SeHCAT) test. Low-certainty evidence supports sequestrant treatment, including colesevelam. We aimed to determine the efficacy and safety of colesevelam in bile acid diarrhoea.

METHODS

In this randomised, double-blind, placebo-controlled, investigator-initiated phase 4 trial of the sequestrant colesevelam in bile acid diarrhoea (SINBAD), we enrolled consecutive patients aged 18-79 years without inflammatory bowel disease attending SeHCAT testing for suspected bile acid diarrhoea at four Danish secondary care centres. Participants were randomly allocated 1:1 to receive 12 days of treatment with colesevelam (overencapsulated tablets of 625 mg) or placebo, with the starting dose of two capsules twice daily and titrated to effect during the first 5 days of treatment. A pharmacist independent of the clinical investigators generated a randomisation list on the web page randomization.com using block randomisation (randomisation was not stratified). C4 and SeHCAT diagnostic results were blinded during treatment. We treated all patients with diarrhoea, with a daily mean of 3·0 or more bowel movements or 1·0 or more watery bowel movements (Bristol stool scale type 6 and 7). Remission was defined as the absence of both these criteria during treatment days 6-12. The primary outcome was the intention-to-treat remission rate in bile acid diarrhoea diagnosed by C4 concentration greater than 46 ng/mL. A secondary outcome was the intention-to-treat remission rate in bile acid diarrhoea diagnosed by SeHCAT retention of 10% or less. This trial is registered with ClinicalTrials.gov, NCT03876717.

FINDINGS

Between Oct 25, 2018, and July 1, 2021, 168 patients were randomly assigned to receive colesevelam (n=84) or placebo (n=84). 41 patients had C4 concentration greater than 46 ng/mL (22 assigned to the colesevelam group and 19 to the placebo group). For the C4-defined primary outcome, 14 (64%) of 22 participants receiving colesevelam versus three (16%) of 19 participants receiving placebo achieved remission (adjusted odds ratio 9·1, 95% CI 1·9-62·8; p=0·011). For the SeHCAT-defined secondary outcome, 75 of the 168 participants had retention of less than 10% (37 assigned to the colesevelam group and 38 assigned to the placebo group); 22 (59%) of 37 participants receiving colesevelam achieved remission versus five (13%) of 38 participants receiving placebo (adjusted odds ratio 11·1, 95% CI 3·4-45·6; p=0·00020). There were no serious adverse events. Common adverse events were transient. For patients receiving colesevelam within the primary outcome population, five had abdominal pain, nine had bloating, and four had nausea. For patients receiving placebo, four had abdominal pain, four had bloating, and one had nausea. No participants with bile acid diarrhoea withdrew due to adverse events.

INTERPRETATION

Colesevelam was superior to placebo at inducing remission of bile acid diarrhoea diagnosed with C4 concentration greater than 46 ng/mL. Secondary outcome data suggest similar efficacy treating SeHCAT-defined bile acid diarrhoea. Colesevelam was safe during the treatment.

FUNDING

Fabrikant Vilhelm Pedersen og hustrus mindelegat; recommended by the Novo Nordisk Foundation.

Usefulness of colestimide for diarrhea in postoperative Crohn's disease

Background and Aim

Crohn's disease (CD) often causes intractable diarrhea after intestinal resection. Anion exchange resins have been reported to be effective in patients with bile acid diarrhea after distal ileectomy; furthermore, bile acid metabolism has been implicated in the pathogenesis of CD. Therefore, we aimed to examine the effectiveness of colestimide in the management of postoperative CD, and to compare its impact between patients with and those without ileocecal resection.

Methods

Postoperative CD patients prescribed colestimide for diarrhea between April 2017 and December 2020 were retrospectively evaluated for changes in the total Crohn's disease activity index (CDAI), each CDAI component including diarrhea frequency/week, albumin, and C‐reactive protein (CRP) was evaluated before and after the administration of colestimide. Furthermore, comprehensive patient and physician assessments were reviewed from medical records during the first outpatient visit as a global clinical judgment after the initiation of colestimide therapy.

Results

A total of 24 patients were included, of whom 17 had a previous history of ileocecal resection. Significant improvement was noted in CDAI and diarrhea frequency only in the ileocecal resection group (CDAI: 114.5 ± 52.7 and 95.4 ± 34.8, P < 0.05; diarrhea frequency/week 23.8 ± 14.1 and 15.4 ± 11.2, P < 0.05, respectively). There was no significant improvement in other CDAI components, albumin level, or CRP level in either group. In the global clinical judgment, 13 and 4 patients in the ileocecal and non‐ileocecal resection groups, respectively, were judged as “effective,” with an overall efficacy rate of 70.8%.

Conclusion

Colestimide is effective for diarrhea in patients with postoperative CD, especially after ileocecal resection.

Advances in the Comprehensive Management of Postoperative Crohn's Disease

Patients with postoperative Crohn's disease are difficult to manage because of their risk of experiencing a more severe course, multiple symptom confounders, and poor sensitivity of symptomatic remission to rule out intestinal inflammation. In this group, data are lacking on biologic therapeutic efficacy, and recommendations are lacking for those with multiple medication failures. Novel noninvasive testing can simultaneously exclude alternate causes of symptoms (serum C4, fecal fat, small intestinal bowel overgrowth breath testing) and assess intestinal inflammation (fecal calprotectin, endoscopic healing index). In addition, endoscopy-based disease activity assessment and management are required. Endoscopy should be performed within 6 months of surgery, and aggressive disease activity monitoring can be considered with colonoscopy every 1-2 years subsequently to ensure late recurrence is detected. Patients with multiple resections should be screened for short bowel syndrome. Predictive biomarkers are needed to guide medication selection in this high-risk population. Postoperative prophylactic biologic therapy is prudent for patients with preoperative biologic failure. However, there are no high-quality data to guide which agent should be selected. Selecting biologics with an alternative mechanism of action in those who had failed a biologic with adequate drug concentrations and selection of different agents in those with previous intolerance are reasonable. Significantly more study is required to assess the efficacy of therapies in this setting.

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.

Pathophysiology and Clinical Management of Bile Acid Diarrhea

Bile acid malabsorption (BAM) represents a common cause of chronic diarrhea whose prevalence is under-investigated. We reviewed the evidence available regarding the pathophysiology and clinical management of bile acid diarrhea (BAD). BAD results from dysregulation of the enterohepatic recirculation of bile acids. It has been estimated that 25–33% of patients with functional diarrhea and irritable bowel syndrome with diarrhea have BAM. Currently, the selenium homotaurocholic acid test is the gold standard for BAD diagnosis and severity assessment. However, it is an expensive method and not widely available. The validation of the utility in the clinical practice of several other serum markers, such as 7α-hydroxy-4-cholesten-3-one (C4) and the fibroblast growth factor 19 (FGF19) is ongoing. The first-line treatment of patients with BAD is bile acid sequestrants. Patients that are refractory to first-line therapy should undergo further diagnostics to confirm the diagnosis and to treat the underlying cause of BAD. An early and correct diagnosis of BAD would improve patient’s quality of life, avoiding additional diagnostic tests that burden health care systems. Considering the limited availability and tolerability of specific medications for BAD treatment, future research is awaited to identify other therapeutic approaches, such as gut microbiota modulating therapies.

Dietary nutrients mediate crosstalk between bile acids and gut microbes in animal host metabolism

Bile acids (BAs) are synthesized by liver, then gut microbes embellish primary BAs into secondary BAs with diverse and biological functions. Over the past few decades, amounts of evidences demonstrated the importance of gut microbes in BA metabolism. There is also significant evidence that BAs are regarded as cell signals in gut-liver, gut-brain, and gut-testis axis. Moreover, the interaction between BAs and gut microbes plays a key role not only in the absorption and metabolism of nutrients, but the regulation of immune function. Herein, we collected the major information of the BA metabolism-related bacteria, nutrients, and cell signals, focused on the possible molecular mechanisms by "Microbes-Bile acids" crosstalk, highlighted the gut-liver, gut-brain, and gut-testis axis, and discussed the possibility and application of the regulation of BA metabolism by nutrients.

Bile Acid Diarrhea in Adults and Adolescents

BACKGROUND

Bile acids are central to enterohepatic signaling pathways activated through natural receptors, farnesoid X receptor [FXR mediates synthesis of fibroblast growth factor-19 (FGF-19)], and G protein-coupled bile acid receptor 1 (GPBAR1, also known as TGR5). Although bile acid diarrhea (BAD) is more commonly encountered in ileal resection or disease, there is evidence documenting "idiopathic" BAD in about 20% of adolescents and 30% of adults presenting with chronic, non-bloody diarrhea often attributed to irritable bowel syndrome. Mechanism(s) leading to increased hepatic synthesis and colonic bile acid levels in "idiopathic" BAD include reduced synthesis of FGF-19 by the ileal mucosa, or genetic variation in hepatocyte proteins klotho β and FGF receptor 4 (FGFR4) that mediate negative feedback of bile acid synthesis.

PURPOSE

The objective of this review is to summarize the diagnosis of BAD in adults and adolescents. In addition to ⁷⁵ SeHCAT retention for diagnosis of BAD, studies have validated fasting serum 7αC4 and FGF-19, respectively, by-product and inhibitor of hepatic bile acid synthesis, as well as fecal bile acid measurements. These assays are widely available through reference laboratories, and they are being simplified (eg, measurement of primary fecal bile acids in a random stool sample). BAD has also been identified as a co-factor contributing to persistent diarrhea in other diseases in remission including inflammatory bowel disease, microscopic colitis, celiac disease, and neuroendocrine tumors. In summary, advances in diagnosis of BAD provide opportunities for generalists and pediatric and adult gastroenterologists to provide targeted treatment for BAD presenting as chronic non-bloody diarrhea.

Downregulation of Serum and Distal Ileum Fibroblast Growth Factor19 in Bile Acid Diarrhoea Patients

BACKGROUND

Bile acid diarrhoea or BAD is a common but little recognised cause of chronic diarrhoea. Few of these patients in China have been diagnosed due to a lack of diagnostic options.

AIMS

To clarify the diagnostic value of serum fibroblast growth factor19 (FGF19) in BAD patients.

METHODS

We reported on 60 chronic diarrhoea patients and 80 healthy volunteers (HV). Based on the 90th percentile levels of serum 7a-hydroxy-4-cholesten-3-one (C4) of HV, these patients were divided into BAD group (C4 ≥ 90th) and non-bile acid diarrhoea group (NBAD, C4 < 90th). Serum FGF19 in the two clinical groups and HV group were compared, as was distal ileum FGF19 in clinical groups. The diagnostic value of serum FGF19 for BAD was evaluated.

RESULTS

The 90th percentile of serum C4 in HV group was 65.87 ng/ml. Serum FGF19 concentrations in BAD group (Median 69.28 pg/ml; n = 23) were significantly lower than those in HV (Median 122.18 pg/ml; n = 80) and NBAD (Median 129.57 pg/ml; n = 29) groups. FGF19 mRNA of the distal ileum in BAD group, was lower than that in NBAD group, P = 0.002. The rate of FGF19 protein low expression of distal ileum in BAD and NBAD group were 78.3% and 48.3%, P = 0.027. Using an ROC curve, statistical analysis yielded a threshold FGF19 concentration of 117.3 pg/ml (AUC, 0.906; 91.3% sensitivity, 79.3% specificity) for a clinical diagnosis of BAD.

CONCLUSIONS

Serum and distal ileum expression of FGF19 significantly decreased in BAD patients. The suggested clinical ranges for serum FGF19 < 117.3 pg/ml has high sensitivity and specificity for BAD patients with a normal structural and histological ileum.

A case of COVID-19 diarrhea relieved by bile acid sequestrant administration

Patients with coronavirus disease 2019 exhibit various gastrointestinal symptoms. Although diarrhea is reported in many cases, the pathophysiology of diarrhea has not been fully clarified. Herein, we report a case of coronavirus disease 2019 with diarrhea that was successfully relieved by the administration of a bile acid sequestrant. The patient was a 59-year-old man whose pneumonia was treated by the administration of glucocorticoids and mechanical ventilation. However, beginning on the 30th hospital day, he developed severe watery diarrhea (up to 10 times a day). Colonoscopy detected ulcers in the terminal ileum and ascending colon. The oral administration of a bile acid sequestrant, colestimide, improved his diarrhea quickly. Ileal inflammation is reported to suppress expression of the gut epithelial apical sodium-dependent bile acid transporter. It decreases bile acid absorption at the distal ileum and increases colonic delivery of bile acids, resulting in bile acid diarrhea. In summary, the clinical course of the case presented in this report suggests that bile acid diarrhea is a possible mechanism of watery diarrhea observed in patients with coronavirus disease 2019.

Making a Confident Diagnosis of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is among the most common diagnoses made by medical providers and its symptoms are common causes for health care consultation. IBS is characterized by abdominal pain associated with abnormal stool consistency and/or frequency and is widely considered a diagnosis of exclusion, despite abundant evidence contradicting such an approach. A positive diagnosis is achieved through application of symptom-based clinical criteria, careful history and physical examination, evaluation for alarm sign/symptoms, and judicious use of diagnostic testing. This article reviews the symptom-based criteria for IBS and utility of diagnostic tests commonly included in the evaluation of IBS symptoms.

SLC10A2 deficiency-induced congenital chronic bile acid diarrhea and stunting

Background

Diarrhea is a common occurrence in children below the age of 5 years. In chronic cases, it induces malnutrition that severely stunts growth. Bile acid diarrhea (BAD), caused by malabsorption of bile acid (BA), is a rare form of chronic diarrhea seldom observed in pediatric patients. Here, we present a clinical report on a novel case of chronic BAD, with severe stunting in an infant, induced by a homozygous mutation of SLC10A2.

Methods

We performed DNA extraction, whole‐exome sequencing analysis, and mutation analysis of SLC10A2 to obtain genetic data on the patient. We subsequently analyzed the patient's clinical and genetic data.

Results

The patient's clinical manifestations were chronic diarrhea with increased BAs in the feces and extreme stunting, which was diagnosed as BAD. A homozygous mutation of SLC10A2 at the c.313T>C (rs201206937) site was detected.

Conclusion

Our report reveals the youngest case illustrating the characteristics of BAD induced by genetic variant at 313T>C, and the second case entailing a clear association between a SLC10A2 genetic mutation and the onset of BAD. Our findings expand the mutant spectrum of the SLC10A2 gene and contribute to the refinement of the genotype–phenotype mapping of severe stunting induced by pediatric BAD. Moreover, they highlight the value of molecular genetic screening for diagnosing BAD in young patients.

What Are the Pearls and Pitfalls of the Dietary Management for Chronic Diarrhoea?

Chronic diarrhoea affects up to 14% of adults, it impacts on quality of life and its cause can be variable. Patients with chronic diarrhoea are presented with a plethora of dietary recommendations, often sought from the internet or provided by those who are untrained or inexperienced. In this review, we summarise the possible causes of chronic diarrhoea that can be managed by diet, the symptom improvement and quality of life benefits but also the potential risks of such dietary treatments. Clinicians need to consider both the benefits and risks of dietary treatments before making dietary recommendations to manage chronic diarrhoea. The pivotal role that dietitians have in ensuring optimal symptom improvement without jeopardising nutritional and overall health is discussed.

Prevalence and clinical features of bile acid diarrhea in patients with chronic diarrhea

OBJECTIVE

Bile acid diarrhea is a form of chronic diarrhea caused by excessive bile reaching the colon. Conditions involving the terminal ileum and cholecystectomy are predisposing factors but an idiopathic form of bile acid diarrhea has also been described. In this study we aimed to evaluate the prevalence of bile acid diarrhea in patients consecutively evaluated for chronic diarrhea in an Outpatient Gastroenterology Clinic.

METHODS

Medical records of all patients admitted for chronic diarrhea (>4 weeks) between June 2018 and April 2019 were retrospectively reviewed. Bile acid diarrhea was suspected in patients with ileal disease, cholecystectomy or post-prandial diarrhea. Patients' age at diagnosis, sex, presenting symptoms, results of main test and examinations, final diagnoses and date of last follow-up visit were also collected. Exclusion of chronic diarrhea of other causes and a 6-month clinical improvement with cholestyramine treatment confirmed the diagnosis of bile acid diarrhea.

RESULTS

In total, 139 patients aged 46 ± 20 years (76 women and 63 men) were included. Diarrhea due to an organic cause was diagnosed in 16 patients. A clinical response to cholestyramine persisting for more than 6 months led to a diagnosis of bile acid diarrhea in 39 (aged 52 ± 19 years) out of the remaining 123 patients with functional forms of diarrhea. Therefore, the prevalence of bile acid diarrhea was 28.1% (95% confidence interval 19.9%-38.4%) in patients with chronic diarrhea.

CONCLUSIONS

Bile acid diarrhea is a very common, yet under-recognized cause of chronic functional diarrhea. A therapeutic trial of cholestyramine is a valid diagnostic strategy.

Biochemical Diagnosis of Bile Acid Diarrhea: Prospective Comparison With the 75Seleno-Taurohomocholic Acid Test

INTRODUCTION

The diagnosis of bile acid diarrhea is often missed because the availability of the seleno-taurohomocholic acid (SeHCAT) test is limited. We aimed to compare the biomarkers 7α-hydroxy-4-cholesten-3-one (C4) and fibroblast growth factor 19 (FGF19) with the SeHCAT test.

METHODS

Patients with chronic diarrhea without intestinal resection referred for SeHCAT were prospectively recruited for this diagnostic accuracy study. Blood was sampled at fasting and after a stimulation meal with chenodeoxycholic acid. SeHCAT retention ≤10% defined bile acid diarrhea and >10% defined miscellaneous diarrhea. Receiver operating characteristics (ROC) were analyzed with SeHCAT as the gold standard. www.clinicaltrials.gov (NCT03059537).

RESULTS

Patients with bile acid diarrhea (n = 26) had mean C4 of 30 ng/mL (95% confidence interval: 19-46) vs 8 (7-11; P < 0.001) in the miscellaneous diarrhea group (n = 45). Area under the ROC curve (ROCAUC) for C4 was 0.83 (0.72-0.93). C4 < 15 ng/mL had 85% (74%-96%) negative predictive value; C4 > 48 ng/mL had 82% (59%-100%) positive predictive value. Twenty patients had C4 values 15-48 ng/mL, of whom 11/20 had SeHCAT ≤10%. Median fasting FGF19 was 72 pg/mL (interquartile range: 53-146) vs 119 (84-240) (P = 0.004); ROCAUC was 0.71 (0.58-0.83). Stimulated FGF19 responses did not differ (P = 0.54).

DISCUSSION

We identified C4 thresholds with clinically useful predictive values for the diagnosis of and screening for bile acid diarrhea in patients with chronic watery diarrhea. Further validation of the cutoff values with the placebo-controlled effect of sequestrant therapy is warranted (see Visual Abstract, Supplementary Digital Content 2, http://links.lww.com/AJG/B603).

Making the Diagnosis of Bile Acid Diarrhea

Bile acid diarrhea is a frequent, treatable cause of functional diarrhea but is difficult to diagnose when the nuclear medicine seleno-taurohomocholic acid test is unavailable. An alternative approach is testing blood for the bile acid precursor, 7α-OH-4-cholesten-3-one, which is raised with increased bile acid synthesis. A recent article has defined measurements that have high negative and positive predictive values, further exploring how they can be improved by incorporating measures such as age, stool number, fibroblast growth factor 19, or plasma sulfated bile acids. Other articles have looked at the percentage of fecal primary bile acids. Together, they promise better use of diagnostic biomarkers for this condition.

Functional Bowel Disease

Functional bowel disorders refer to disorders of gut-brain interaction that affect the intestinal tract. Irritable bowel syndrome (IBS) is the most common functional bowel disorder and affects individuals regardless of age and gender. It can result in impaired quality of life and significant health care utilization and is therefore important to recognize and manage. The diagnosis of IBS is based on clinical symptoms. IBS is categorized based on predominant bowel habit (constipation, diarrhea, mixed, or unclassified), and the treatment of IBS is individually tailored based on subtype and symptom severity.

The Role of Bile Acids in Chronic Diarrhea

Bile acids (BAs) are the central signals in enterohepatic communication, and they also integrate microbiota-derived signals into enterohepatic signaling. The tissue distribution and signaling pathways activated by BAs through natural receptors, farsenoid X receptor and G protein-coupled BA receptor 1 (GPBAR1, also known as Takeda G-coupled receptor 5), have led to a greater understanding of the mechanisms and potential therapeutic agents. BA diarrhea is most commonly encountered in ileal resection or disease, in idiopathic disorders (with presentation similar to functional diarrhea or irritable bowel syndrome with diarrhea), and in association with malabsorption such as chronic pancreatitis or celiac disease. Diagnosis of BA diarrhea is based on Se-homocholic acid taurine retention, 48-hour fecal BA excretion, or serum 7αC4; the latter being a marker of hepatic BA synthesis. BA diarrhea tends to be associated with higher body mass index, increased stool weight and stool fat, and acceleration of colonic transit. Biochemical markers of increased BA synthesis or excretion are available through reference laboratories. Current treatment of BA diarrhea is based on BA sequestrants, and, in the future, it is anticipated that farsenoid X receptor agonists may also be effective. The optimal conditions for an empiric trial with BA sequestrants as a diagnostic test are still unclear. However, such therapeutic trials are widely used in clinical practice. Some national guidelines recommend definitive diagnosis of BA diarrhea over empirical trial.

Ten Reasons to Think About Bile Acids in Managing Inflammatory Bowel Disease

There are ten good reasons why it is important to think about abnormalities in bile acid control in inflammatory bowel disease. Before reviewing these reasons, it is relevant to review essential elements in the enterohepatic circulation, synthesis and actions of bile acids.

High prevalence of primary bile acid diarrhoea in patients with functional diarrhoea and irritable bowel syndrome-diarrhoea, based on Rome III and Rome IV criteria

BACKGROUND

A high prevalence of primary bile acid diarrhoea (BAD) has been reported for Rome III defined irritable bowel syndrome (IBS)-diarrhoea and functional diarrhoea. We determined whether this still applies under the contemporaneous Rome IV criteria, given that the latter characterises IBS-diarrhoea as having more frequent abdominal pain compared with previous iterations, whilst no longer recognising abdominal discomfort.

METHODS

Patients referred for a 75SeHCAT test completed a baseline questionnaire comprising, i) demographic data, ii) risk factors for BAD (inflammatory bowel disease, bowel resection, cholecystectomy, microscopic colitis, celiac disease, abdominal-pelvic radiotherapy), iii) the Rome III and IV bowel disorder questionnaire, and iv) mood and somatisation scores. A diagnosis of BAD constituted a 75SeHCAT of ≤15%, with moderate to severe disease being defined as ≤10% and ≤5%, respectively.

FINDINGS

Of 300 patients with complete dataset, 184 had no risk factors for BAD and fulfilled criteria for either IBS-diarrhoea or functional diarrhoea. The prevalence of primary BAD was 38% (n = 70/184), with almost half having moderate (n = 16) to severe (n = 17) disease. Using the Rome III criteria, the prevalence of primary BAD was 36% in IBS-diarrhoea (n = 63/173) and 64% (n = 7/11) in functional diarrhoea; p = 0.11. Using the Rome IV criteria, the prevalence of primary BAD was 38% (n = 53/139) in IBS-diarrhoea and 38% (n = 17/45) in functional diarrhoea; p = 0.97. Patients with primary BAD experienced more frequent loose stools (p = 0.01) and had a higher body mass index (p<0.0001) compared to those without BAD, but otherwise no significant differences were seen in age, gender, mood, somatisation, or abdominal pain. The presence of primary BAD in patients classified as overweight or obese was approximately 40% and 60%, respectively.

INTERPRETATION

Over a third of patients with Rome IV IBS-diarrhoea or functional diarrhoea have primary BAD, similar to Rome III. We therefore recommend that, in secondary care settings, generic testing for primary BAD should be considered in patients presenting with chronic diarrhoea of presumed functional origin regardless of concomitant abdominal pain. Centres that lack tests for primary BAD, and who empirically treat instead, may consider targeting patients who are overweight or obese.

Bile Acid Diarrhea and NAFLD: Shared Pathways for Distinct Phenotypes

Irritable bowel syndrome with diarrhea (IBS-D) and NAFLD are both common conditions that may be influenced by shared pathways of altered bile acid (BA) signaling and homeostatic regulation. Pathophysiological links between IBS-D and altered BA metabolism include altered signaling through the ileal enterokine and fibroblast growth factor 19 (FGF19) as well as increased circulating levels of 7α-hydroxy-4-cholesten-3-one, a metabolic intermediate that denotes increased hepatic BA production from cholesterol. Defective production or release of FGF19 is associated with increased BA production and BA diarrhea in some IBS-D patients. FGF19 functions as a negative regulator of hepatic cholesterol 7α-hydroxylase; therefore, reduced serum FGF19 effectively de-represses hepatic BA production in a subset of IBS-D patients, causing BA diarrhea. In addition, FGF19 modulates hepatic metabolic homeostatic response signaling by means of the fibroblast growth factor receptor 4/klotho beta receptor to activate cascades involved in hepatic lipogenesis, fatty acid oxidation, and insulin sensitivity. Emerging evidence of low circulating FGF19 levels in subsets of patients with pediatric and adult NAFLD demonstrates altered enterohepatic BA homeostasis in NAFLD. Conclusion: Here we outline how understanding of shared pathways of aberrant BA homeostatic signaling may guide targeted therapies in some patients with IBS-D and subsets of patients with NAFLD.