Evaluation of chronic diarrhea and irritable bowel syndrome with diarrhea in adults in the era of precision medicine

Algorithms or biomarkers in patients with lower DGBI?

BACKGROUND

Several organizations have proposed guidelines or clinical decision tools for the management of patients with disorders of gut-brain interactions (DGBI) affecting the lower digestive tract including irritable bowel syndrome and chronic idiopathic constipation. Such algorithms are based on sequential therapeutic trials and modifying the treatment strategy based on efficacy and adverse events.

PURPOSE

The aims of this review are to evaluate the evidence for efficacy of second- and third-line pharmacotherapies and to assess the evidence for the alternative option to manage subgroups of patients with symptoms suggestive of lower DGBI based on diagnostic tests or documented dysfunctions. The preeminent tests to identify such subgroups that present with symptoms that overlap with lower DGBI are detailed: digital rectal examination as well as anorectal manometry and balloon expulsion for evacuation disorders, detailed measurements of colonic transit, and diagnosis of bile acid diarrhea or carbohydrate malabsorption based on biochemical measurements. The review also addresses the cost implications of screening to exclude alternative diagnoses and the costs of therapy associated with the therapeutic options following an algorithmic approach to treatment from the perspective of society, insurer, or patient. Finally, the costs of the diagnostic tests to identify actionable biomarkers and the evidence of efficacy of individualized therapy based on formal diagnosis or documentation of abnormal functions are detailed in the review.

Getting the BS out of Irritable Bowel Syndrome with Diarrhea (IBS-D): Let's Make a Diagnosis

PURPOSE OF REVIEW

Irritable bowel syndrome with diarrhea (IBS-D) is diagnosed when chronic symptoms of abdominal pain accompany loose stools, and alarm features, such as fever, anemia, rectal bleeding, and weight loss are absent. This combination of symptoms makes structural disorders, such as inflammatory bowel disease or cancer, unlikely, but does not exclude other conditions that cause these symptoms. The question is whether making a "positive diagnosis" of IBS-D based on symptoms alone and instituting therapy based on that diagnosis still makes sense.

RECENT FINDINGS

Clinical observations suggest that at least two-thirds of cases of IBS-D can be explained by three mechanisms: a) food intolerances (~ 30-40%), b) bile acid diarrhea (~ 20-30%), and c) disturbed microbial flora (~ 15-20%). Other conditions that are less frequent but can cause IBS symptoms or be confused with IBS include: celiac disease, microscopic colitis, mastocytosis/mast cell activation, and drug side-effects. Many cases of IBS-D have a discoverable, underlying cause that can direct therapy more efficiently.

Co-occurrence of fecal incontinence with constipation or irritable bowel syndrome indicates the need for personalized treatment

BACKGROUND

This study aimed to compare the prevalence and symptoms of fecal incontinence (FI) in relation to irritable bowel syndrome (IBS-associated FI), constipation (constipation-associated FI), and isolation (isolated FI).

METHODS

Data were analyzed from 3145 respondents without organic comorbidities known to influence defecation function from the general Chinese population who filled in the online Groningen Defecation and Fecal Continence questionnaire. FI, IBS, and constipation were evaluated with the Rome IV criteria.

KEY RESULTS

The prevalence of FI was 10.5% (n = 329) in the non-comorbidity group. After multivariable logistic regression analysis, IBS (odds ratio [OR]: 12.55, 95% confidence interval [CI]: 9.06-17.36) and constipation (OR: 4.38, 95% CI: 3.27-5.85) were the most significant factors contributing to FI. Based on this finding, 106/329 (32.2%) had IBS-associated FI, 119/329 (36.2%) had constipation-associated FI, and 104/329 (31.6%) had isolated FI. Among the 329 FI respondents, there was a high prevalence of IBS and constipation-related symptoms, including abdominal pain (81.5%) and abdominal bloating (77.8%) for IBS and straining during defecation (75.4%), incomplete defecation (72.3%), defecation blockage (63.2%), anal pain during defecation (59.3%), and hard stools (24%) for constipation. The patients with IBS-associated FI asked for specialists' help less frequently than those with isolated FI. Interestingly, among the patients with constipation-associated FI, 56.3% used anti-diarrhea medicine.

CONCLUSIONS AND INFERENCES

The prevalence of IBS-associated FI, constipation-associated FI, and isolated FI is comparably high. It is important to diagnose and target the cause of FI to provide personalized and cause-targeting care instead of treating only the FI 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.

Opioids in the Treatment of Chronic Idiopathic Diarrhea in Humans—A Systematic Review and Treatment Guideline

In patients with chronic idiopathic diarrhea resistant to standard treatment, opioids are often used as rescue therapy. This systematic review investigated opioid effects on gut function in chronic diarrhea. PubMed and Embase were searched regarding effects of opioid agonists on the gastrointestinal tract in humans with chronic or experimentally induced diarrhea. A total of 1472 relevant articles were identified and, after thorough evaluation, 11 clinical trials were included. Generally, studies reported a reduction in stool frequency and an increase in transit time during treatment with the opioid receptor agonists loperamide, asimadoline, casokefamide, and codeine compared with placebo. Loperamide and diphenoxylate significantly improved stool consistency compared with placebo, whereas asimadoline showed no such effects. Compared with placebo, loperamide treatment caused less abdominal pain and urgency. Asimadoline showed no significant subjective improvements, but fedotozine was superior to placebo in reducing abdominal pain and bloating in selected patients. Only two relevant studies were published within the last 20 years, and standardized endpoint measures are lacking. Most trials included few participants, and further evidence is needed from larger, prospective studies. Likewise, consensus is needed to standardize endpoints for stool frequency, transit time, and consistency to conduct future meta-analyses on opioids in management of chronic idiopathic diarrhea.

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.

Obesity is associated with colitis in women but not necessarily causal relationship

The relationship between obesity and female risk of microscopic colitis remains to be discussed.

Bile acid-gut microbiota crosstalk in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction with an increasing prevalence, and its precise aetiology remains unclear. Gut microbiota dysbiosis has been found to be associated with IBS pathogenesis. In addition, a high incidence of bile acid diarrhoea and disturbed bile acid metabolism has been observed in IBS patients. The abundant microorganisms inhabited in human gut have essential functions in bile acid biotransformation, and can immensely affect the size and constitution of bile acid pool. Meanwhile, the alterations of bile acid profile can inversely interfere with the gut microbiota. This review discussed the role of intricate correlations between bile acids and gut microbiota in IBS pathogenesis and delineated the possible molecular mechanisms, mainly the signalling induced by farnesoid X receptor and transmembrane G protein-coupled receptor 5. Besides, some biomarkers for identifying bile acid diarrhoea in IBS population were listed, assisting the diagnosis and classification of IBS. Moreover, it also assessed some therapeutic strategies for IBS that regulate the bile acid-gut microbiota axis, such as dietary modulation, probiotics/prebiotics, faecal microbiota transplantation, and antibiotics. Collectively, this article illustrated the relationship between bile acids and gut microbiota in IBS pathophysiology and might offer some novel therapeutic options for IBS.

Abnormal findings on abdominopelvic cross-sectional imaging in patients with microscopic colitis: a retrospective, multicenter study

OBJECTIVES

Patients with microscopic colitis may have subtle macroscopic findings on colonoscopy such as erythema, edema, or altered vascular pattern; however, radiographic abnormalities on cross-sectional imaging have not been investigated. We aimed at identifying the abdominopelvic radiographic abnormalities in patients with microscopic colitis, as well as possible correlation with endoscopic findings and the need for extended duration of treatment.

MATERIALS AND METHODS

This was a retrospective study of patients with biopsy-proven microscopic colitis at two tertiary centers between 1 January 2010 and 30 April 2020. Patients underwent computed tomography scan or magnetic resonance imaging within 30 days of a diagnostic flexible sigmoidoscopy or colonoscopy. Patients with colon ischemia and other causes of colitis were excluded. Radiographic abnormalities from imaging reports included bowel wall thickening, mucosal hyperenhancement and mesenteric fat stranding. Univariate and multivariable logistic regression models were used to identify predictors of radiographic abnormalities.

RESULTS

498 patients with microscopic colitis underwent abdominopelvic cross-sectional imaging within 30 days of flexible sigmoidoscopy/colonoscopy. Lymphocytic colitis was diagnosed in 54.6% of patients, and collagenous colitis in 45.4%. Endoscopic and radiographic abnormalities were identified in 16.1% and 12.4% of patients, respectively. Radiographic abnormalities were associated with the need for budesonide therapy (p = .029) and budesonide therapy long-term (p = .0028). Budesonide therapy long-term (p = .047) was associated with radiographic abnormalities in multivariate analysis.

CONCLUSIONS

Radiographic abnormalities may be present on abdominopelvic cross-sectional imaging in a minority of patients with biopsy-proven microscopic colitis, suggesting cross-sectional imaging has low clinical value in the evaluation and treatment of this disease.

Is the Medium Still the Message? Culture-Independent Diagnosis of Gastrointestinal Infections

Infectious diarrhea is caused by a variety of pathogens, including viruses, bacteria, and parasitic organisms. Though the causative agent of diarrhea has historically been evaluated via stool cultures, recently, culture-independent diagnostic tests (CIDT) have been developed and utilized with increasing frequency. Current practice guidelines recommend their use as adjuncts to stool cultures for diagnosing acute and chronic diarrhea. The three principal CIDT are microscopy, enzyme-based immunoassays (EIAs), and molecular based polymerase chain reaction (PCR). This review explores the common causes of infectious diarrhea, the basics of stool culture, the diagnostic utility of these three culture-independent modalities, and the strengths and weaknesses of all currently available clinical techniques. It also outlines considerations for specific populations including returning travelers and those with inflammatory bowel disease.

Prevalence and risk factor for chronic diarrhea in participants of a Japanese medical checkup

BACKGROUND AND AIM

Although chronic diarrhea is a major digestive disorder, it has not been well studied. The aims of this study were to investigate the prevalence and risk factors of chronic diarrhea in the Japanese population and to assess the relationship between stool type and frequency and symptoms related to chronic diarrhea.

METHOD

A total of 13 668 adults who underwent a medical checkup at MedCity21 were enrolled, and 9540 who met the inclusion criteria participated in the study. Participants with chronic diarrhea were defined as those who typically had a Bristol Stool Form Scale of type 6 or 7.

RESULTS

The prevalence of chronic diarrhea was 3.0%. The risk factors for chronic diarrhea were younger age (odds ratio [OR] 0.984, 95% confidence interval [CI] 0.972-0.996), male sex (OR = 2.270, CI = 1.730-2.960), alcohol intake on ≥5 days per week (OR = 2.390, CI = 1.860-3.060), not getting adequate sleep (OR = 0.712, CI = 0.559-0.907), skipping breakfast ≥3 times a week (OR = 1.490, CI = 1.120-1.980), and absence of diabetes mellitus (OR = 0.384, CI = 0.179-0.824). Only 23.5% of the participants in the diarrhea group had ≥3 bowel movements per day. Chronic diarrhea was significantly associated with heartburn, nausea, stomach ache, abdominal bloating and distension, and feeling of stress.

CONCLUSIONS

Our study shows that chronic diarrhea is common in Japan with a prevalence of 3.0%; unique risk factors related to gender, age, and irregular lifestyle were identified. An understanding of bowel habit in the healthy population is helpful for the assessment of change in bowel habit associated with gastrointestinal disorders.

Lactobacillus plantarum CCFM1143 Alleviates Chronic Diarrhea via Inflammation Regulation and Gut Microbiota Modulation: A Double-Blind, Randomized, Placebo-Controlled Study

Irritable bowel syndrome with diarrhea and functional diarrhea are both functional bowel disorders that cause chronic diarrhea. Chronic diarrhea is closely related to daily life and the psychological condition of diarrhea in patients, and probiotics can play a significant role in alleviating chronic diarrhea in some research. Lactobaccilus plantarum CCFM1143 can relieve diarrhea in mice caused by enterotoxigenic Escherichia coli (ETEC); however, its clinical effects remain unclear. This study aimed to assess the effects of CCFM1143 as a therapy for chronic diarrhea patients. Fifty-five patients with chronic diarrhea were randomly assigned into the probiotic group (n = 28) and the placebo group (n = 27), receiving the routine regimen with or without probiotics for 4 weeks, respectively. CCFM1143 can mitigate the apparent clinical symptoms and improve the health status and quality of life of patients. In addition, it could inhibit the increase in interleukin 6 (IL-6) and the decrease in motilin; modulate the short-chain fatty acids, especially acetic and propionic acids; and regulate the gut microbiota, particularly reducing the abundance of Bacteroides and Eggerthella and enriching the abundance of Akkermansia, Anaerostipes, and Terrisporobacter. In addition, treatment with probiotics showed clinical effectiveness in managing chronic diarrhea when compared with the placebo group. The findings could help to develop and further the application of probiotics for chronic diarrhea.

Cost Analysis of Diagnostic Endoscopic Procedures for Chronic Diarrhoea

Chronic diarrhoea is a common condition that affects up to 5% of the population which heavily affects the quality of life for the patient. The British Society of Gastroenterology guidelines recommend that for those who suffer with chronic diarrhoea, a colonoscopy with a biopsy is recommended to exclude microscopic colitis. This retrospective audit included 147 patients who received endoscopic procedures in 2019 at Walsall Manor Hospital for chronic diarrhoea. The results show that a total of £56,797 was incurred through endoscopic and histological investigation with four patients (2.6%) diagnosed with microscopic colitis. Given the lack of diagnostic yield, there is room for advancement in the current guidelines for managing persistent diarrhoea.

Development of a Score to Predict Positive Colonic Histology in Chronic Diarrhea Assessed in Open-access Colonoscopy

GOALS

To evaluate the diagnostic yield of colonoscopy and esophagogastroduodenoscopy with biopsies and to identify predictors of positive colonic histology in patients with chronic diarrhea.

BACKGROUND

Colonoscopy with biopsies is performed in chronic diarrhea with negative initial work-up.

STUDY

We reviewed electronic medical records of 1022 consecutive patients with chronic diarrhea referred for a first colonoscopy (including 25% open-access referrals). Predictors of positive colonic histology were investigated using logistic regression.

RESULTS

Four hundred thirteen patients with macroscopically normal colon were divided into derivation (n=275) and validation (n=138) cohorts. All patients underwent colonoscopy; 369 had ileoscopy (biopsies in 43%), and 289 underwent esophagogastroduodenoscopy (duodenal biopsies in 93%). In patients with endoscopically normal colon, histology was positive in 13.3%: 10.6% microscopic colitis; 1.5% other colitides. Among 358 patients with negative histology, the recorded diagnoses were: 48% unexplained, 25% irritable bowel syndrome, 5.6% small intestinal bacterial overgrowth, and 4.7% bile acid diarrhea. The rates of diagnoses based on positive histologies were 4% for ileal and 5% for duodenal biopsies. Older age [odds ratio (OR)=1.05] was a positive predictor, whereas body mass index (OR=0.93) and duration of diarrhea (OR=0.98) were negative predictors of positive histology. A clinical diagnostic scoring system could correctly predict 41% to 54% of patients with normal colonic histology, with a false-negative rate of 0.8% to 2.6% and a negative predictive value of 95% to 98%.

CONCLUSIONS

Positive colonic biopsies were detected in <15% of patients with chronic diarrhea with normal colonoscopy; a clinical score correctly predicts likelihood of normal histology in about half the patients.

Approach to the adult patient with chronic diarrhea: A literature review

Chronic diarrhea is defined by symptoms lasting longer than 4 weeks. It is a common problem that affects up to 5% of the adult population. Different pathophysiologic mechanisms involve numerous causes, including drug side effects, postoperative anatomic and physiologic alterations, intestinal and colonic wall abnormalities, inflammatory or malabsorption causes, pancreatobiliary diseases, and functional or gut-brain axis disorders associated with dysbiosis or gastrointestinal motility alterations. Due to such a broad differential diagnosis, it is important to categorize chronic diarrhea into five main groups: drug side effect, postoperative, postinfectious, malabsorptive, inflammatory, and functional. The present review is a narrative analysis of the diagnostic approach, emphasizing key aspects of the clinical history, the utility of biomarkers (in breath, stool, urine, and serology) and malabsorption and motility tests, the role of radiologic and endoscopic studies, and the most common histologic findings. A diagnostic algorithm aimed at determining etiology and personalizing therapy is also proposed.

Approach to the adult patient with chronic diarrhea: a literature review

Chronic diarrhea is defined by symptoms lasting longer than 4 weeks. It is a common problem that affects up to 5% of the adult population. Different pathophysiologic mechanisms involve numerous causes, including drug side effects, postoperative anatomic and physiologic alterations, intestinal and colonic wall abnormalities, inflammatory or malabsorption causes, pancreatobiliary diseases, and functional or gut-brain axis disorders associated with dysbiosis or gastrointestinal motility alterations. Due to such a broad differential diagnosis, it is important to categorize chronic diarrhea into five main groups: drug side effect, postoperative, postinfectious, malabsorptive, inflammatory, and functional. The present review is a narrative analysis of the diagnostic approach, emphasizing key aspects of the clinical history, the utility of biomarkers (in breath, stool, urine, and serology) and malabsorption and motility tests, the role of radiologic and endoscopic studies, and the most common histologic findings. A diagnostic algorithm aimed at determining etiology and personalizing therapy is also proposed.

The Role of Purported Mucoprotectants in Dealing with Irritable Bowel Syndrome, Functional Diarrhea, and Other Chronic Diarrheal Disorders in Adults

Chronic diarrhea is a frequent presenting symptom, both in primary care medicine and in specialized gastroenterology units. It is estimated that more than 5% of the global population suffers from chronic diarrhea. and that about 40% of these subjects are older than 60 years. The clinician is frequently faced with the need to decide which is the best therapeutic approach for these patients. While the origin of chronic diarrhea is diverse, impairment of intestinal barrier function, dysbiosis. and mucosal micro-inflammation are being increasingly recognized as underlying phenomena characterizing a variety of chronic diarrheal diseases. In addition to current pharmacological therapies, there is growing interest in alternative products such as mucoprotectants, which form a mucoadhesive film over the epithelium to reduce and protect against the development of altered intestinal permeability, dysbiosis, and mucosal micro-inflammation. This manuscript focuses on chronic diarrhea in adults, and we will review recent evidence on the ability of these natural compounds to improve symptoms associated with chronic diarrhea and to exert protective effects for the intestinal barrier.

Food intolerance/malabsorption may occur in rare diseases

Sugars including lactose and fructose, or proteins (gluten), or biogenic amines (histamine), and combinations thereof may cause food intolerance/malabsorption. However, in usually asymptomatic patients with rare diseases, who present with functional, non-specific, non-allergic gastrointestinal (GI) complaints the etiologic factors of food intolerance/malabsorption need to be evaluated. We summarize patients with rare diseases, such as primary epiploic appendagitis, beta-thalassemias minor, Gullo syndrome and anomaly of the inferior vena cava, who presented functional, non-specific, non-allergic GI complaints. As conclusion, these GI symptoms in patients with otherwise asymptomatic, rare diseases were due to fructose malabsorption, histamine-, lactose intolerance and Helicobacter pylori (H.p.) infection. A registered and experienced dietician was employed to design an individually-tailored diet which ensured effective treatments and H.p. infection was accordingly eradicated.

Undiagnosed microscopic colitis: a hidden cause of chronic diarrhoea and a frequently missed treatment opportunity

Microscopic colitis (MC) is a treatable cause of chronic, non-bloody, watery diarrhoea, but physicians (particularly in primary care) are less familiar with MC than with other causes of chronic diarrhoea. The colon in patients with MC is usually macroscopically normal. MC can only be diagnosed by histological examination of colonic biopsies (subepithelial collagen band >10 µm (collagenous colitis) or >20 intraepithelial lymphocytes per 100 epithelial cells (lymphocytic colitis), both with lamina propria inflammation). The UK National Health Service exerts downward pressure to minimise colonoscopy referrals. Furthermore, biopsies are often not taken according to guidelines. These factors work against MC diagnosis. In this review, we note the high incidence of MC (comparable to ulcerative colitis and Crohn's disease) and its symptomatic overlap with irritable bowel syndrome. We also highlight problems with the recommendation by National Health Service/National Institute for Health and Care Excellence guidelines for inflammatory bowel diseases that colonoscopy referrals should be based on a faecal calprotectin level of ≥100 µg/g. Faecal calprotectin is <100 µg/g in over half of individuals with active MC, building into the system a propensity to misdiagnose MC as irritable bowel syndrome. This raises important questions-how many patients with MC have already been misdiagnosed, and how do we address this silent burden? Clarity is needed around pathways for MC management; MC is poorly acknowledged by the UK healthcare system and it is unlikely that best practices are being followed adequately. There is an opportunity to identify and treat patients with MC more effectively.

Lactulose Breath Testing as a Predictor of Response to Rifaximin in Patients With Irritable Bowel Syndrome With Diarrhea

OBJECTIVES

The nonsystemic antibiotic rifaximin is indicated for irritable bowel syndrome with diarrhea (IBS-D) in adults; however, determinants of response remain unclear. The utility of lactulose breath testing (LBT) in predicting response to rifaximin was examined.

METHODS

Adults with IBS-D received open-label rifaximin 550 mg 3 times daily for 2 weeks, followed by a 4-week posttreatment assessment period. Thirteen centers prospectively participated in this substudy. LBT was conducted before (day 1) and after (day 14) therapy (breath samples obtained every 15 minutes; up to 240 minutes). Patient response (decrease from baseline of ≥30% in abdominal pain and ≥50% decrease in frequency of mushy/watery stool), symptom improvement, and the relationship of clinical outcomes to LBT results were assessed.

RESULTS

A total of 93 patients were included; 62 (66.7%) had positive baseline LBT results. Overall, 48.4% (45/93) of patients responded to rifaximin; of these, 59.7% (37/62) had a positive baseline LBT vs 25.8% (8/31) with a negative LBT (P = 0.002; odds ratio 4.3, 95% confidence interval, 1.5-12.7). Patients with a positive baseline LBT result experienced significantly greater improvement from baseline in 6 of 7 individual IBS symptoms. LBT results after rifaximin therapy did not correlate with clinical response in the 86 patients with evaluable breath tests (P = 0.21); however, patients whose LBT results normalized after rifaximin had the highest response rate of 76.5% (13/17).

DISCUSSION

A positive baseline LBT result predicted a higher likelihood of response to rifaximin in IBS-D, suggesting a gut microbiome modulatory mechanism of action for rifaximin.

Idiopathic chronic diarrhea associated with dysbiosis in a captive cynomolgus macaque (Macaca fascicularis)

Chronic inflammatory enteric diseases occur commonly in humans and animals, especially in captive bred macaques. However, information about the etiology of idiopathic chronic inflammatory diarrhea in cynomolgus monkeys is limited. In this paper, we reported the unusual case of idiopathic chronic diarrhea in a captive cynomolgus monkey based on microbial, imaging, and microbiome examinations.

Chronic Diarrhea Evaluation in the Elderly: IBS or Something Else?

PURPOSE OF REVIEW

Chronic diarrhea is a common problem in all age groups but is a particularly challenging diagnostic problem in the elderly, since many different conditions need to be considered. The purpose of this review is to discuss the evaluation of chronic diarrhea in older individuals. It highlights those conditions that seem to occur with increased frequency in the elderly, discusses the diagnostic tests that are of greatest value in sorting out these problems, and presents an approach to evaluation that is both practical and affordable.

RECENT FINDINGS

There appears to be little value in distinguishing irritable bowel syndrome with diarrhea (IBS-D) from functional diarrhea in most patients, including older individuals. Both conditions need a thoughtful analysis of potential causes that may lead to more focused treatment. Older individuals may be more at risk of having certain structural disorders, and these need to be considered when constructing a differential diagnosis. In addition, elderly patients may have atypical presentations of specific disorders that require an increased index of suspicion. Diagnostic tests generally seem to perform well in older patients but have not been validated in this cohort of patients. Although the pretest probabilities of certain diseases are different in the elderly, the conventional algorithm for assessment of chronic diarrhea should lead to a diagnosis in most cases. Better studies are needed to adequately quantitate the likelihood of different diagnoses and the operating characteristics of diagnostic tests in older patients with chronic diarrhea. Lacking that information, physicians can still do a good job of making a diagnosis in these patients by adopting a stepwise approach.

Tripling the Bioavailability of Rosuvastatin Calcium Through Development and Optimization of an In-Situ Forming Nanovesicular System

In situ forming nanovesicular systems (IFNs) were prepared and optimized to improve Rosuvastatin calcium (RC) oral bioavailability through increasing its solubility and dissolution rate. The IFN was composed of Tween^® 80 (T80), cetyl alcohol (CA), in addition to mannitol or Aerosil 200. A single simple step was adopted for preparation, then the prepared formulations were investigated by analyzing their particle size (PS), polydispersity index (PDI), Zeta potential (ZP), entrapment efficiency (EE), and flowability properties. D-optimal design was applied to choose the optimized formulations. The maximum desirability values were 0.754 and 0.478 for the optimized formulations containing 0.05 g CA, 0.18 g T80, and 0.5 g mannitol (OFM) or Aerosil (OFA), respectively. In vitro drug release from the optimized formulations showed a significantly faster dissolution rate when compared to the market product. In vivo performance of the optimized formulations in rabbits was investigated after filling them into enteric-coated capsules. Ultimately, OFA formulation achieved a 3 times increase in RC oral bioavailability in comparison with the market product, supporting the hypothesis of considering IFNs as promising nanocarriers able to boost the bioavailability of BCS class II drugs.