Drug-induced diarrhea

Anti-adipogenic Effects of Sulforaphane-rich Ingredient with Broccoli Sprout and Mustard Seed in 3T3-L1 Preadipocytes

Glucoraphanin (GRA) is a precursor of sulforaphane (SFN), which can be synthesized by the enzyme myrosinase. In this study, we developed and validated HPLC analytical methods for the determination of GRA and SFN in mustard seed powder (MSP), broccoli sprout powder (BSP), and the MSP-BSP mixture powder (MBP), and evaluated their anti-adipogenic effects in 3T3-L1 adipocytes. We found that the analysis methods were suitable for the determination of GRA and SFN in MSP, BSP, and MBP. The content of GRA in BSP was 131.11 ± 1.84 µmol/g, and the content of SFN in MBP was 162.29 ± 1.24 µmol/g. In addition, BSP and MBP effectively decreased lipid accumulation content without any cytotoxicity. Both BSP and MBP significantly inhibited the expression of adipogenic proteins and increased the expression of proteins related to lipolysis and lipid metabolism. BSP and MBP inhibited the expression of adipocyte protein 2 (aP2), CCAAT/enhancer-binding protein-α (C/EBP-α), and peroxisome proliferator-activated receptor-γ (PPAR-γ) in 3T3-L1 adipocytes, and inhibited the expression of fatty acid synthase (FAS) through AMP-activated protein kinase (AMPK). Meanwhile, BSP and MBP also increased the expression of the lipolysis-related proteins, uncoupling protein-1 (UCP-1) and carnitine palmitoyltransferase-1 (CPT-1). Moreover, MBP exerted anti-adipogenic to a greater extent than BSP in 3T3-L1 preadipocytes.

A Review of Preclinical Tools to Validate Anti-Diarrheal Agents

BACKGROUND

Since their inception, preclinical experimental models have played an important role in investigating and characterizing disease pathogenesis. These in vivo, ex vivo, and in vitro preclinical tests also aid in identifying targets, evaluating potential therapeutic drugs, and validating treatment protocols.

INTRODUCTION

Diarrhea is a leading cause of mortality and morbidity, particularly among children in developing countries, and it represents a huge health-care challenge on a global scale. Due to its chronic manifestations, alternative anti-diarrheal medications must be tested and developed because of the undesirable side effects of currently existing anti-diarrheal drugs.

METHODS

Several online databases, including Science Direct, PubMed, Web of Science, Google Scholar and Scopus, were used in the literature search. The datasets were searched for entries of studies up to May, 2022.

RESULTS

The exhaustive literature study provides a large number of in vivo, in vitro and ex vivo models, which have been used for evaluating the mechanism of the anti-diarrheal effect of drugs in chemically-, pathogen-, disease-induced animal models of diarrhea. The advances and challenges of each model were also addressed in this review.

CONCLUSION

This review encompasses diverse strategies for screening drugs with anti-diarrheal effects and covers a wide range of pathophysiological and molecular mechanisms linked to diarrhea, with a particular emphasis on the challenges of evaluating and predictively validating these experimental models in preclinical studies. This could also help researchers find a new medicine to treat diabetes more effectively and with fewer adverse effects.

COVID-19 and diarrhea: putative mechanisms and management

BACKGROUND

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of the coronavirus disease 2019 (COVID-19), has recently posed a threat to global health by spreading at a high rate and taking millions of lives worldwide. Along with the respiratory symptoms, there are gastrointestinal manifestations and one of the most common gastrointestinal symptoms is diarrhea which is seen in a significant percentage of COVID-19 patients.

LITERATURE REVIEW

Several studies have shown the plausible correlation between overexpressed angiotensin converting enzyme 2 (ACE2) in enterocytes and SARS-CoV-2, as ACE2 is the only known receptor for the virus entry. Along with the dysregulated ACE2, there are other contributing factors such as gut microbiome dysbiosis, adverse effects of antiviral and antibiotics for treating infections and inflammatory response to SARS-CoV-2 which bring about increased permeability of gut cells and subsequent occurrence of diarrhea. Few studies found that the SARS-CoV-2 is capable of damaging liver cells too. No single effective treatment option is available.

LIMITATIONS

Confirmed pathophysiology is still unavailable. Studies regarding global population are also insufficient.

CONCLUSION

In this review, based on the previous works and literature, we summarized the putative molecular pathophysiology of COVID-19 associated diarrhea, concomitant complications and the standard practices of management of diarrhea and hepatic manifestations in international setups.

Nonsteroidal anti-inflammatory drug exposure and the risk of microscopic colitis

BACKGROUND

Medication consumption has been suggested as a risk factor for microscopic colitis (MC), but studies of varying design have yielded inconsistent results. Our aim was to evaluate the association between medications and MC.

METHODS

A hybrid cohort of prospectively identified patients undergoing colonoscopy with biopsies for suspicion of MC (N = 144) and patients with MC enrolled within three months of diagnosis into an MC registry (N = 59) were surveyed on medication use. Medication use was compared between patients with and without diagnosis of MC by chi-squared test and binomial logistic regression adjusted for known risk factors of MC: age and gender.

RESULTS

In total, 80 patients with MC (21 new, 59 registry) were enrolled. Patients with MC were more likely to be older (p = 0.03) and female (p = 0.01) compared to those without MC. Aspirin and other non-steroidal anti-inflammatory drugs were more commonly used among patients who developed MC (p < 0.01). After controlling for age and gender, these medications remained independent predictors of MC with odds ratio for any non-steroidal anti-inflammatory drug use of 3.04 (95% CI: 1.65-5.69). No association between MC and other previously implicated medications including proton pump inhibitors and selective serotonin reuptake inhibitors was found.

CONCLUSIONS

In this cohort of patients with chronic diarrhea, we found use of aspirin and non-steroidal anti-inflammatory drugs, but not other implicated medications to be associated with the development of MC. Whether these drugs trigger colonic inflammation in predisposed hosts or worsen diarrhea in undiagnosed patients is unclear. However, we feel that these findings are sufficient to discuss potential non-steroidal anti-inflammatory drug cessation in patients newly diagnosed with MC.

Diarrhea in Placebo Arms of Cancer Studies

BACKGROUND/AIM

Diarrhea is among the most common adverse events in early oncology clinical trials, and drug causality may be difficult to determine.

MATERIALS AND METHODS

This is a systematic literature review of placebo arms of randomized cancer trials.

RESULTS

Anemia was reported in 95 of 127 placebo monotherapy cohorts. Publications involving healthy volunteers and cancer prevention studies reported lower frequencies than those with cancer patients. The average reported frequency of diarrhea grade 1 or higher among studies in cancer patients was 15%. The maximal reported frequencies for grades 1, 2, 3, 4, 5 were 56, 24, 6, 2, and 0%, respectively.

CONCLUSION

When higher diarrhea frequencies than those are observed in treatment arms of clinical trials, then drug causality is likely.

Ginsenoside compound K- a potential drug for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory and autoimmune disease, if prescription of effective delayed, the articular disturbances may lead to disability. Ginsenoside compound K (GCK) is the main degradation product of oral ginsenosides in the human intestine. Numerous researches in vitro and in vivo have recorded the anti-arthritic effect of GCK, we discuss the mechanisms from the following three aspects, including anti-inflammatory, immune-regulatory, and bone-protective, respectively, in this review, and the anti-arthritic mechanism of GCK may be related to the effect on TNF-α-TNFR2, glucocorticoid receptor (GR) and β-arrestin1/2. We also describe the anti-anemia effect of GCK to open the possibility that GCK can be used as an effective disease-modifying anti-rheumatic drug (DMARD).

Effects of Ethanol Extracts from Grateloupia elliptica, a Red Seaweed, and Its Chlorophyll Derivative on 3T3-L1 Adipocytes: Suppression of Lipid Accumulation through Downregulation of Adipogenic Protein Expression

Grateloupia elliptica (G. elliptica) is a red seaweed with antioxidant, antidiabetic, anticancer, anti-inflammatory, and anticoagulant activities. However, the anti-obesity activity of G. elliptica has not been fully investigated. Therefore, the effect of G. elliptica ethanol extract on the suppression of intracellular lipid accumulation in 3T3-L1 cells by Oil Red O staining (ORO) was evaluated. Among the eight red seaweeds tested, G. elliptica 60% ethanol extract (GEE) exhibited the highest inhibition of lipid accumulation. GEE was the only extract to successfully suppress lipid accumulation among ethanol extracts from eight red seaweeds. In this study, we successfully isolated chlorophyll derivative (CD) from the ethyl acetate fraction (EA) of GEE by high-performance liquid chromatography and evaluated their inhibitory effect on intracellular lipid accumulation in 3T3-L1 adipocytes. CD significantly suppressed intracellular lipid accumulation. In addition, CD suppressed adipogenic protein expression such as sterol regulatory element-binding protein-1 (SREBP-1), peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer-binding protein-α (C/EBP-α), and fatty acid binding protein 4 (FABP4). Taken together, our results indicate that CD from GEE inhibits lipid accumulation by suppressing adipogenesis via the downregulation of adipogenic protein expressions in the differentiated adipocytes. Therefore, chlorophyll from G. elliptica has a beneficial effect on lipid metabolism and it could be utilized as a potential therapeutic agent for preventing obesity.

Common Diarrheal Illnesses in the Elderly

Diarrhea is a fairly common problem among the elderly that has a higher morbidity and mortality compared with the general population. There are multiple reasons for diarrhea in the elderly that can be stratified by different mechanisms: infectious, osmotic, secretory, inflammatory, and malabsorptive. Oral hydration and dietary management are the basic management principles for all forms of diarrhea but specific treatment should address the root cause of diarrhea in order to improve outcomes.

Safety of systemic treatments for Behçet's syndrome

INTRODUCTION

Treatment of Behçet's syndrome (BS) is aimed at controlling all symptoms of such a complex disorder, ensuring a good quality of life and preventing life-threatening complications. A better understanding of the pathogenic role of different chemokines has improved our knowledge of BS and elicited a more specific use of therapies currently available, minimizing the burden of potential side-effects related to treatment.

AREAS COVERED

This work aims to provide a detailed overview of the safety profile for current therapies available in the treatment of BS, focusing on the main side-effects, toxicity and contraindications.

EXPERT OPINION

The greatest experience in the management of BS has been achieved with the employment of monoclonal anti-tumor necrosis factor antibodies which have been advocated for BS refractory manifestations. Moreover, interleukin-1 inhibitors have proven to be effective as well as safe, despite escalation of their dosage, especially to manage the most severe and difficult-to-treat ocular manifestations. However, general treatment of BS patients remains awkward as protean clinical features may respond differently to the same treatment or even worsen. Therefore, patients' safety for therapies used in BS promotes the implementation of precision medicine, which could help targeting accurately the pathogenetic mechanisms concealed behind specific clinical phenotypes.

Human 3D Gastrointestinal Microtissue Barrier Function As a Predictor of Drug-Induced Diarrhea

Drug-induced gastrointestinal toxicities (GITs) rank among the most common clinical side effects. Preclinical efforts to reduce incidence are limited by inadequate predictivity of in vitro assays. Recent breakthroughs in in vitro culture methods support intestinal stem cell maintenance and continual differentiation into the epithelial cell types resident in the intestine. These diverse cells self-assemble into microtissues with in vivo-like architecture. Here, we evaluate human GI microtissues grown in transwell plates that allow apical and/or basolateral drug treatment and 96-well throughput. Evaluation of assay utility focused on predictivity for diarrhea because this adverse effect correlates with intestinal barrier dysfunction which can be measured in GI microtissues using transepithelial electrical resistance (TEER). A validation set of widely prescribed drugs was assembled and tested for effects on TEER. When the resulting TEER inhibition potencies were adjusted for clinical exposure, a threshold was identified that distinguished drugs that induced clinical diarrhea from those that lack this liability. Microtissue TEER assay predictivity was further challenged with a smaller set of drugs whose clinical development was limited by diarrhea that was unexpected based on 1-month animal studies. Microtissue TEER accurately predicted diarrhea for each of these drugs. The label-free nature of TEER enabled repeated quantitation with sufficient precision to develop a mathematical model describing the temporal dynamics of barrier damage and recovery. This human 3D GI microtissue is the first in vitro assay with validated predictivity for diarrhea-inducing drugs. It should provide a platform for lead optimization and offers potential for dose schedule exploration.

Do north-eastern German pharmacies recommend a necessary medical consultation for acute diarrhoea? Magnitude and determinants using a simulated patient approach

Background: In Germany, non-pharmacists (pharmacy technicians and pharmaceutical technical assistants) are permitted to advise on and sell medications in addition to pharmacists. The aim of this study was to determine if pharmacists and non-pharmacists referred patients to a medical consultation for a scenario in which consulting a doctor was mandatory ('appropriate outcome') and what the quality of questioning and - if a medication was dispensed - the quality of information provided were in this context. The study also aimed to determine which factors predicted a necessary referral to a doctor. Methods: A cross-sectional, covert simulated patient study was conducted in a random sample of community pharmacies stratified by location in the German state of Mecklenburg-Vorpommern. Each pharmacy was visited once by one of four trained investigators. They simulated a symptom-based request involving a grandmother with acute diarrhoea. A multivariate binary logistic regression analysis using potential variables from bivariate analysis was carried out to determine the predictors for a referral to a doctor. Results: All 199 planned visits were conducted. A necessary referral to a doctor was recommended in 59.8% (n=119) of all visits. The most commonly asked question was 'for whom is the medication?' (75.4%, n=150), while 'clarification by a doctor' was asked the least (17.6%, n=35). In 87.9% (n=175) of all visits a medication was dispensed. Multivariate analysis revealed that, unlike pharmacists, non-pharmacists have a 2.446 times higher likelihood of recommending a referral to a doctor (p = 0.044; 95% CI = 1.025-5.835). Conclusions: In almost half of the visits a necessary referral to a doctor was not recommended. Furthermore, the quality of questioning and the quality of information were below expectations. Moreover, involvement of non‑pharmacists was surprisingly identified as a relevant factor influencing the appropriate outcome.

Do north-eastern German pharmacies recommend a necessary medical consultation for acute diarrhoea? Magnitude and determinants using a simulated patient approach

Background: To determine if pharmacy staff in Germany referred patients to a medical consultation for a scenario in which consulting a doctor was mandatory ('appropriate outcome') and what the quality of questioning and - if a medication was dispensed - the quality of information provided were in this context. Moreover, to determine which factors predicted a necessary referral to a doctor. Methods: A cross-sectional covert simulated patient study was conducted in a random sample of community pharmacies stratified by location in the German state of Mecklenburg-Vorpommern. Each pharmacy was visited once by one of four trained investigators. They simulated a symptom-based request involving a grandmother with acute diarrhoea. A multivariate binary logistic regression analysis using potential variables from bivariate analysis was carried out to determine the predictors for a referral to a doctor. Results: All 199 planned visits were conducted. A necessary referral to a doctor was recommended in 59.8% (n=119) of all test purchases. Multivariate analysis revealed that a non-pharmacist as opposed to a pharmacist and two or more questions as opposed to no questions were significantly associated with a referral to a doctor. Conclusions: Regarding the necessary referral to a doctor, an enormous potential for improvement was revealed for community pharmacies in the German state of Mecklenburg-Vorpommern. The results should make both the Mecklenburg-Vorpommern pharmacy association and legislators aware of the need to significantly escalate their quality management efforts.

Cross-sectional study of the prevalence, causes and management of hospital-onset diarrhoea

BACKGROUND

The National Health Service in England advises hospitals collect data on hospital-onset diarrhoea (HOD). Contemporaneous data on HOD are lacking.

AIM

To investigate prevalence, aetiology and management of HOD on medical, surgical and elderly-care wards.

METHODS

A cross-sectional study in a volunteer sample of UK hospitals, which collected data on one winter and one summer day in 2016. Patients admitted ≥72 h were screened for HOD (definition: ≥2 episodes of Bristol Stool Type 5-7 the day before the study, with diarrhoea onset >48 h after admission). Data on HOD aetiology and management were collected prospectively.

FINDINGS

Data were collected on 141 wards in 32 hospitals (16 acute, 16 teaching). Point-prevalence of HOD was 4.5% (230/5142 patients; 95% confidence interval (CI) 3.9-5.0%). Teaching hospital HOD prevalence (5.9%, 95% CI 5.1-6.9%) was twice that of acute hospitals (2.8%, 95% CI 2.1-3.5%; odds ratio 2.2, 95% CI 1.7-3.0). At least one potential cause was identified in 222/230 patients (97%): 107 (47%) had a relevant underlying condition, 125 (54%) were taking antimicrobials, and 195 (85%) other medication known to cause diarrhoea. Nine of 75 tested patients were Clostridium difficile toxin positive (4%). Eighty (35%) patients had a documented medical assessment of diarrhoea. Documentation of HOD in medical notes correlated with testing for C. difficile (78% of those tested vs 38% not tested, P<0.001). One-hundred and forty-four (63%) patients were not isolated following diarrhoea onset.

CONCLUSION

HOD is a prevalent symptom affecting thousands of patients across the UK health system each day. Most patients had multiple potential causes of HOD, mainly iatrogenic, but only a third had medical assessment. Most were not tested for C. difficile and were not isolated.

Self-limiting diarrhea in an infant exposed to sertraline in breast milk

Sertraline is widely used to treat postpartum depression. Though studies found detectable levels of sertraline in infant blood, very few adverse effects are reported. Reporting hereby is a case of an infant who developed self-limiting diarrhea, probably due to exposure to sertraline in breast milk.

Single- and Multiple-Dose Trials to Determine the Pharmacokinetics, Safety, Tolerability, and Sex Effect of Oral Ginsenoside Compound K in Healthy Chinese Volunteers

Background and objectives: Ginsenoside compound K (CK) is a candidate drug for rheumatoid arthritis therapy. The objective of this study was to investigate the pharmacokinetic properties, safety and tolerability of CK.

Methods: In randomized, double-blind trials, 76 healthy Chinese subjects received 1 of 7 single oral doses (25, 50, 100, 200, 400, 600, 800 mg) of CK or placebo under fasting condition, and another 36 subjects received repeated oral doses (100, 200, or 400 mg) of CK or placebo for up to 9 days a week after a corresponding single dose, after breakfast. Both sexes were equally represented in the two trials. Pharmacokinetic parameters of CK and its metabolite 20(S)-protopanaxadiol (PPD) were calculated and statistically analyzed according to the plasma concentration data. Tolerability was evaluated by adverse events (AEs) and laboratory examinations.

Results: The range of time to maximum concentration (T_max) was 1.5–6.0 h, with a linear increase in the exposure of CK over the dose range of 100–400 mg. Steady state was reached after the 7th administration, and the accumulation index range was 2.60–2.78. Sex differences were characterized by a higher exposure in females than males with the single administration after breakfast. In addition, no severe AEs were observed.

Conclusion: CK was safe and well-tolerated over the treatment period. The sex- and food-related impacts on CK pharmacokinetics need further investigations to be validated. (Registration number: ChiCTR-TRC-14004824 and ChiCTR-IPR-15006107, http://www.chictr.org.cn/index.aspx).

Management of Common Side Effects of Apremilast

Apremilast is a relatively new therapy for the treatment of moderate to severe plaque psoriasis in adults. While this medication is considered safe with a very low risk of serious side effects, a few common (≥5% of patients) mild to moderate side effects have been reported, including diarrhea, nausea, headache, and nasopharyngitis. Not addressing these symptoms may lead to medication nonadherence and unnecessary discontinuation of therapy. These side effects are often easily managed with interventions available to the practicing dermatologist, and in only rare instances will these side effects require dose adjustment or discontinuation of therapy. The purpose of this article is to review common side effects of apremilast at its approved dose of 30 mg orally twice daily (BID) and to provide clear, simple recommendations for their management in dermatological practice.

Spectrum of Drug-induced Chronic Diarrhea

The evaluation of a patient with chronic diarrhea can be quite frustrating, as it is expensive and involves multiple diagnostic studies. Moreover, identification of a drug as a cause of chronic diarrhea is a challenge in patients taking multiple medications. The disease may either be associated with intestinal mucosal changes, mimicking diseases such as celiac disease, or purely functional, with no histopathologic change. Drug-induced diarrhea may or may not be associated with malabsorption of nutrients, and a clinical improvement may occur within days of discontinuation of the drug, or may take longer when associated with mucosal injury. Diarrhea in diabetics, often attributed to poor management and lack of control, may be due to oral hypoglycaemic agents. Chemotherapy can result in diffuse or segmental colitis, whereas olmesartan and a few other medications infrequently induce a disease that mimics celiac disease, but is not associated with gluten intolerance. In short, increased awareness of a drug, as a cause for diarrhea and a clear understanding of the clinical manifestations will help clinicians to solve this challenging problem. This article aims to review drug-induced diarrhea to (a) understand known pathophysiological mechanisms; (b) assess the risk associated with frequently prescribed medications, and discuss the pathogenesis; and

Lecithin-gold hybrid nanocarriers as efficient and pH selective vehicles for oral delivery of diacerein-In-vitro and in-vivo study

We report the synthesis and evaluation of lecithin-gold hybrid nanocarriers for the oral delivery of drugs with improved pharmacokinetics, Au-drug interactive bioactivity and controlled drug releasing behavior at physiological pH inside human body. For this purpose, diacerein, a hydrophobic anti-arthritic drug, was loaded in lecithin NPs (LD NPs), which were further coated by Au NPs either by in-situ production of Au NPs on LD NPs or by employing pre-synthesized Au NPs. All LDAu NPs were found to release drug selectively at the physiological pH of 7.4 and showed 2.5 times increase in the oral bioavailability of diacerein. Pharmacological efficacy was significantly improved i.e., greater than the additive effect of diacerein and Au NPs alone. LDAu NPs started suppressing inflammation at first phase, whereas LD NPs showed activity in the second phase of inflammation. These results indicate the interaction of Au NPs with prostaglandins and histaminic mediators of first phase of carrageenan induced inflammation. Acute toxicity study showed no hepatic damage but the renal toxicity parameters were close to the upper safety limits. Toxicity parameters were dependent on surface engineering of LDAu NPs. Apart from enhancing the oral bioavailability of hydrophobic drugs and improving their anti-inflammatory activity, these hybrid nanocarriers may have potential applications in gold-based photothermal therapy and the tracing of inflammation at atherosclerotic and arthritic site.

The yield of stool testing in hospital-onset diarrhea: Has evidence changed practice?

INTRODUCTION

Aside from examination for Clostridium difficile, the yield of stool testing in hospital-onset diarrhea is poor. Clinical practice guidelines discourage overzealous stool testing in patients with diarrhea that develops after the third hospital day. However, the adoption of this recommendation into clinical practice is limited. Furthermore, the effect of microbiology laboratory improvements on hospital-onset diarrhea testing is largely unknown.

METHODS

A retrospective cohort study was conducted in a university-affiliated community-hospital and included all adult inpatients who developed diarrhea after hospitalization.

RESULTS

132 adult patients (53% female) developed diarrhea after hospitalization in 2013. The cohort's mean age was 55.6 years. 46.2% of patients developed diarrhea in the first 3 days of hospitalization. Testing for parasites was negative in all examined 67 samples. Testing for C. difficile was positive in 13 cases (10.8%) out of 120 tested samples. Testing for other pathogens was positive in 1 sample (Campylobacter) out of 129 samples. Stool samples tested in the first 3 days of hospitalization were more likely to be positive (64.3 vs 35.7%, p = 0.1). Change in management was reported in 9 out of 14 patients (64.3%) with positive stool testing compared with 31 out of 118 patients (26.3%) with negative stool testing, p = 0.01.

CONCLUSION

Despite improvements in stool samples' testing, the yield continues to be low, especially in hospital-onset diarrhea past the third hospital day. Physicians' embracement of the '3-day rule' continues to be poor.

The pharmacologic treatment of short bowel syndrome: new tricks and novel agents

Short bowel syndrome (SBS) is a manifestation of massive resection of the intestines resulting in severe fluid, electrolyte, and vitamin/mineral deficiencies. Diet and parenteral nutrition play a large role in the management of SBS; however, pharmacologic options are becoming more readily available. These pharmacologic agents focus on reducing secretions and stimulating intestinal adaptation. The choice of medication is highly dependent on the patient's symptoms, remaining anatomy, and risk versus benefit profile for each agent. This article focuses on common and novel pharmacologic medications used in SBS, including expert advice on their indications and use.

Gastro 2013 APDW/WCOG Shanghai working party report: chronic diarrhea: definition, classification, diagnosis

Diarrhea is best defined as passage of loose stools often with more frequent bowel movements. For clinical purposes, the Bristol Stool Form Scale works well to distinguish stool form and to identify loose stools. Laboratory testing of stool consistency has lagged behind. Acute diarrhea is likely to be due to infection and to be self-limited. As diarrhea becomes chronic, it is less likely to be due to infection; duration of 1 month seems to work well as a cut-off for chronic diarrhea, but detailed scientific knowledge is missing about the utility of this definition. In addition to duration of diarrhea, classifications by presenting scenario, by pathophysiology, and by stool characteristics (e.g. watery, fatty, or inflammatory) may help the canny clinician refine the differential diagnosis of chronic diarrhea. In this regard, a careful history remains the essential part of the evaluation of a patient with diarrhea. Imaging the intestine with endoscopy and radiographic techniques is useful, and biopsy of the small intestine and colon for histological assessment provides key diagnostic information. Endomicroscopy and molecular pathology are only now being explored for the diagnosis of chronic diarrhea. Interest in the microbiome of the gut is increasing; aside from a handful of well-described infections because of pathogens, little is known about alterations in the microbiome in chronic diarrhea. Serological tests have well-defined roles in the diagnosis of celiac disease but have less clearly defined application in autoimmune enteropathies and inflammatory bowel disease. Measurement of peptide hormones is of value in the diagnosis and management of endocrine tumors causing diarrhea, but these are so rare that these tests are of little value in screening because there will be many more false-positives than true-positive results. Chemical analysis of stools is of use in classifying chronic diarrhea and may limit the differential diagnosis that must be considered, but interpretation of the results is still evolving. Breath tests for assessment of carbohydrate malabsorption, small bowel bacterial overgrowth, and intestinal transit are fraught with technical limitations that decrease sensitivity and specificity. Likewise, tests of bile acid malabsorption have had limited utility beyond empirical trials of bile acid sequestrants.

Histological spectrum of mycophenolate mofetil-related colitis: association with apoptosis

AIMS

The main purpose of this study was to define diagnostic histological characteristics of mycophenolate mofetil (MMF)-related colitis in association with crypt epithelial cell turnover.

METHODS AND RESULTS

The examined material included 43 colonic biopsies from renal transplant recipients with MMF administration and persistent diarrhoea. Thirty-three cases showed MMF-related colitis, while 10 showed no significant changes. The histological findings were scored and correlated with the apoptotic index (AI) and with the proliferation rate (PR) of the crypt epithelium examined by TUNEL assay and Ki-67 immunoexpression. Ten cases of Crohn disease and 10 of ulcerative colitis were used as comparative groups. Crypt distortion and loss as well as increased apoptosis constituted the main features, their degree and combination leading either to an inflammatory bowel disease (IBD)-like (82%) or to a graft-versus-host disease-like pattern (18%). A high AI was associated more frequently with moderate and severe crypt distortion, while the values were significantly higher compared with the control groups (P < 0.01). High PR was noted in 18 of 29 (62.1%) of the cases.

CONCLUSIONS

The diagnostic hallmark of MMF-related colitis is an IBD-like histological pattern in association with increased epithelial apoptosis, while apoptotic cell death seems to be a potential pathogenetic factor of mucosa injury.

Definitions, pathophysiology, and evaluation of chronic diarrhoea

Definitions for 'chronic diarrhoea' are arbitrary and are not evidence-based. The duration of illness that would differentiate acute from chronic diarrhoea is often taken as four weeks and serves best to exclude most infectious causes of diarrhoea which run their courses within that time interval. Patients tend to identify loose stool consistency rather than increased frequency of bowel movements when they say that they have diarrhoea. Some patients complaining of diarrhoea have frequent passage of formed stools and some have fecal incontinence. It is incumbent on the treating physician to inquire exactly what is meant by diarrhoea by a given patient. The pathophysiology of diarrhoea is complex, but generally comes down to explaining why there is excess water in stools. This can result from impaired absorption, excess secretion or retention of intraluminal fluid due to osmotic forces generated by poorly absorbed substances. The evaluation of diarrhoea is challenging. An algorithmic approach is feasible.

Nosocomial diarrhea: evaluation and treatment of causes other than Clostridium difficile

Diarrhea is common among hospitalized patients but the causes are distinct from those of diarrhea in the community. We review existing data about the epidemiology of nosocomial diarrhea and summarize recent progress in understanding the mechanisms of diarrhea. Clinicians should recognize that most cases of nosocomial diarrhea have a noninfectious etiology, including medications, underlying illness, and enteral feeding. Apart from Clostridium difficile, the frequency of infectious causes such as norovirus and toxigenic strains of Clostridium perfringens, Klebsiella oxytoca, Staphylococcus aureus, and Bacteroides fragilis remains largely undefined and test availability is limited. Here we provide a practical approach to the evaluation and management of nosocomial diarrhea when tests for C. difficile are negative.

Evaluating the patient with diarrhea: a case-based approach

The evaluation of the patient with diarrhea can be complex and the treatment challenging. In this article, the definition of diarrhea and the pathophysiologic mechanisms that lead to diarrhea are reviewed. A simplified 5-step approach to the patient with diarrhea is provided and applied in a case-oriented manner applicable to everyday clinical practice. On completion of this article, you should be able to (1) define diarrhea, (2) outline various pathophysiologic mechanisms of diarrhea, and (3) describe a simplified 5-step approach to facilitate the evaluation of diarrhea.

[Nosocomial diarrhea]

Hospital acquired or nosocomial diarrhea affects up to one third of hospitalized patients. It increases mortality rates as well as length and costs of the hospital stay. Drug side effects are the predominant cause of nosocomial diarrhea whilst clostridium difficile is the most common infectious agent, whose development is closely linked to antibiotic usage. The causal therapy of mild clostridium difficile infections is controversially discussed. Nevertheless, the use of Metronidazol for mild cases and of vancomycin for severe forms of the disease is recommended. Diarrhea outbreaks might be caused by viruses and less often by Salmonella and Listeria. Norovirus infections are of outstanding importance. Rehydration and isolation to prevent the spread of this highly contagious virus are the only reasonable options as we still lack a proper therapy.

Drug-induced acute liver failure and gastrointestinal complications

The objective of this article is to describe adverse drug events related to the liver and gastrointestinal tract in critically ill patients. PubMed and other resources were used to identify information related to drug-induced acute liver failure, gastrointestinal hypomotility, constipation, diarrhea, gastrointestinal bleeding, and pancreatitis in critically ill patients. This information was reviewed, and data regarding pathophysiology, common drug causes, and guidelines for prevention and management were collected and summarized. In cases in which data in critically ill patients were unavailable, data were extrapolated from other patient populations. Drug-induced acute liver failure can be caused by many drugs routinely used in the intensive care unit and may be associated with significant morbidity and mortality. Drug-related hypomotility and constipation and drug-related diarrhea are reported with many drugs, and these are common adverse drug events in critically ill patients that can substantially complicate the care of these patients. Drug-induced gastrointestinal bleeding and drug-induced pancreatitis occur less frequently, can range in disease severity, and can be associated with morbidity and mortality. Many drugs used in critically ill patients are associated with adverse drug events related to the liver and gastrointestinal tract. Critical care clinicians should be aware of common drug causes of drug-induced acute liver failure, gastrointestinal hypomotility, constipation, diarrhea, gastrointestinal bleeding, and pancreatitis, and should be familiar with the prevention and management of these diverse conditions.

Computational models for drug inhibition of the human apical sodium-dependent bile acid transporter

The human apical sodium-dependent bile acid transporter (ASBT; SLC10A2) is the primary mechanism for intestinal bile acid reabsorption. In the colon, secondary bile acids increase the risk of cancer. Therefore, drugs that inhibit ASBT have the potential to increase the risk of colon cancer. The objectives of this study were to identify FDA-approved drugs that inhibit ASBT and to derive computational models for ASBT inhibition. Inhibition was evaluated using ASBT-MDCK monolayers and taurocholate as the model substrate. Computational modeling employed a HipHop qualitative approach, a Hypogen quantitative approach, and a modified Laplacian Bayesian modeling method using 2D descriptors. Initially, 30 compounds were screened for ASBT inhibition. A qualitative pharmacophore was developed using the most potent 11 compounds and applied to search a drug database, yielding 58 hits. Additional compounds were tested, and their K(i) values were measured. A 3D-QSAR and a Bayesian model were developed using 38 molecules. The quantitative pharmacophore consisted of one hydrogen bond acceptor, three hydrophobic features, and five excluded volumes. Each model was further validated with two external test sets of 30 and 19 molecules. Validation analysis showed both models exhibited good predictability in determining whether a drug is a potent or nonpotent ASBT inhibitor. The Bayesian model correctly ranked the most active compounds. In summary, using a combined in vitro and computational approach, we found that many FDA-approved drugs from diverse classes, such as the dihydropyridine calcium channel blockers and HMG CoA-reductase inhibitors, are ASBT inhibitors.

Diarrhea and malabsorption in the elderly

Acute and chronic diarrheal disorders are common problems at all ages. It has been estimated that 5% to 7% of the population has an episode of acute diarrhea each year and that 3% to 5% have chronic diarrhea that lasts more than 4 weeks. It is likely that the prevalence of diarrhea is similar in older individuals. This article reviews the impact of diarrhea in the elderly, many of whom are less fit physiologically to withstand the effect of diarrhea on fluid balance and nutritional balance.

Pharmacologic consideration of commonly used gastrointestinal drugs in the elderly

Gastrointestinal (GI) manifestations in older adults can be caused or alleviated by drug therapy. GI medications, such as proton pump inhibitors and histamine-2 receptor antagonists, are among the most commonly used medications in long-term care facilities in the United States. This article reviews the alterations in pharmacokinetic disposition of medications that occur with aging and highlights the pharmacology of commonly used GI drugs. Selected GI conditions that are drug induced and preventable are identified, and recommendations for GI drugs to be avoided in older adults are provided.

Review article: Small intestinal bacterial overgrowth, bile acid malabsorption and gluten intolerance as possible causes of chronic watery diarrhoea

BACKGROUND

Chronic watery diarrhoea is one of the most common symptoms prompting GI evaluation. Recently, new diagnostic considerations have emerged as possible factors in chronic diarrhoea.

AIM

To review available data regarding diagnosis and treatment of chronic diarrhoea with an emphasis on bacterial overgrowth and bile acid malabsorption.

METHODS

A systematic search of the English language literature of chronic diarrhoea was performed focused on three possible aetiologies of diarrhoea: small intestinal bacterial overgrowth (SIBO), idiopathic bile salt malabsorption (IBAM), gluten responsive enteropathy.

RESULTS

Recent studies suggest that SIBO and bile acid malabsorption may have been underestimated as possible causes of chronic watery diarrhoea. Gluten intolerance with negative coeliac serology is a contentious possible cause of watery diarrhoea, but requires further research before acceptance as an entity.

CONCLUSION

In patients with otherwise unexplained chronic watery diarrhoea, small intestinal bacterial overgrowth and bile salt malabsorption should be considered and investigated.