Hyperglycemia inhibits mechanoreceptor-mediated gastrocolonic responses and colonic peristaltic reflexes in healthy humans

Risk factors for inadequate bowel preparation before colonoscopy: A meta-analysis

OBJECTIVE

This meta-analysis aimed to comprehensively explore the risk factors for inadequate bowel preparation (IBP).

METHODS

We searched the Embase, PubMed, Web of Science, and The Cochrane Library databases up to August 24, 2023, to identify observational studies and randomized controlled trials (RCTs) that examined risk factors for IBP. A random effects model was used to pool the adjusted odds ratios and 95% confidence intervals.

RESULTS

A total of 125 studies (91 observational studies, 34 RCTs) were included. Meta-analyses of observational studies revealed that three preparation-related factors, namely, characteristics of last stool (solid or brown liquid), incomplete preparation intake, and incorrect diet restriction, were strong predictors of IBP. The other factors were moderately correlated with IBP incidence, including demographic variables (age, body mass index, male sex, Medicaid insurance, and current smoking), comorbidities (diabetes, liver cirrhosis, psychiatric disease, Parkinson's disease, previous IBP, poor mobility, inpatient, and Bristol stool form 1/2), medications (tricyclic antidepressants, opioids, antidepressants, narcotics, antipsychotics, and calcium channel blockers), and preparation-related factors (preparation-to-colonoscopy interval not within 3 to 5/6 h, nonsplit preparation, and preparation instructions not followed). No colonoscopy indications were found to be related to IBP. Meta-analyses of RCTs showed that education, constipation, stroke/dementia, and discomfort during preparation were also moderately associated with IBP. Most of the other findings were consistent with the pooled results of observational studies. However, primarily due to imprecision and inconsistency, the certainty of evidence for most factors was very low to moderate.

CONCLUSIONS

We summarized five categories of risk factors for IBP. Compared to demographic variables, comorbidities, medications, and colonoscopy indications, preparation-related elements were more strongly associated with IBP. These findings may help clinicians identify high-risk individuals and provide guidance for IBP prevention.

Childhood Obesity: An Updated Review

BACKGROUND

Childhood obesity is an important and serious public health problem worldwide.

OBJECTIVE

This article aims to familiarize physicians with the evaluation, management, and prevention of childhood.

METHODS

A PubMed search was conducted in May, 2021, in Clinical Queries using the key terms "obesity" OR "obese". The search included clinical trials, randomized controlled trials, case-control studies, cohort studies, meta-analyses, observational studies, clinical guidelines, case reports, case series, and reviews. The search was restricted to English literature and children. The information retrieved from the above search was used in the compilation of the present article.

RESULTS

Most obese children have exogenous obesity characterized by a growth rate for height above the 50th percentile, normal intelligence, normal genitalia, and lack of historical or physical evidence of an endocrine abnormality or a congenital syndrome. Obese children are at risk for dyslipidemia, hypertension, diabetes mellitus, non-alcoholic fatty liver disease, obstructive sleep apnea, psychosocial disturbances, impaired quality of life, and shorter life expectancy. The multitude of serious comorbidities necessitates effective treatment modalities. Dietary modification, therapeutic exercise, and behavioral modification are the fundamentals of treatment. Pharmacotherapy and/or bariatric surgery should be considered for obese individuals who do not respond to the above measures and suffer from a serious comorbid condition.

CONCLUSION

Childhood obesity, once established, is often refractory to treatment. Most treatment programs lead to a brief period of weight loss, followed by rapid re-accumulation of the lost weight after the termination of therapy. As such, preventive activity is the key to solving the problem of childhood obesity. Childhood obesity can be prevented by promoting a healthy diet, regular physical activity, and lifestyle modification. Parents should be encouraged to get involved in school and community programs that improve their children's nutritional status and physical activity.

Constipation in DM are associated with both poor glycemic control and diabetic complications: Current status and future directions

Constipation is a major complications of diabetes mellitus. With the accelerating prevalence of diabetes worldwide and an aging population, there is considerable research interest regarding the altered function and structure of the gastrointestinal tract in diabetic patients. Despite current advances in hyperglycemic treatment strategies, the specific pathogenesis of diabetic constipation remains unknown. Patients with constipation, may be reluctant to eat regularly, which may worsen glycemic control and thus worsen symptoms associated with underlying diabetic bowel disease. This paper presents a review of the complex relationship between diabetes and constipation, exploring the morphological alterations and biomechanical remodeling associated with intestinal motility dysfunction, as well as alterations in intestinal neurons, cellular signaling pathways, and oxidative stress. Further studies focusing on new targets that may play a role in the pathogenesis of diabetic constipation may, provide new ideas for the development of novel therapies to treat or even prevent diabetic constipation.

Gastrocolic Reflex Is Delayed and Diminished in Adults with Type 1 Diabetes

BACKGROUND

Constipation is a prevalent gastrointestinal complication in diabetes. The pathophysiology may include neural dysfunction and impaired gastrocolic reflex; however, investigation of the latter has been limited in diabetes. Using the wireless motility capsule, we investigated whether the gastrocolic reflex was impaired in adults with type 1 diabetes compared to healthy.

METHODS

One hundred and four adults with type 1 diabetes underwent investigation with the wireless motility capsule and recorded sleep cycle, eating habits, and bowel movements in a diary. Colonic motility index, contraction amplitudes, time-to-peak, peak motility, and colonic transit time were investigated directly in response to a meal. Diagnosis of peripheral (nerve conduction) and autonomic (orthostatic hypotension) polyneuropathy was verified.

RESULTS

In comparison with health, people with diabetes had at the time of ingestion decreased motility index and contraction amplitudes (p < 0.001), prolonged time-to-peak (p = 0.01), and borderline decreased peak motility (p = 0.06), which taken together indicate impaired coordination of the gastrocolic reflex. These features were most prominent in those with concomitant peripheral or autonomic neuropathy. Additionally, they were associated with prolonged colonic transit time (p > 0.01).

CONCLUSIONS

In type 1 diabetes, the gastrocolic reflex was delayed and diminished and further associated with the presence of neuropathy and constipation. These results suggest that impaired reflex is part of the underlying pathogenesis in the development of constipation.

Constipation prevalence in diabetic patients

Objective the aim of this study was to identify the prevalence of constipation in diabetic patients treated at the endocrinology outpatient clinic at Hospital Universitário Professor Alberto Antunes and PAM Salgadinho, from April to August 2013.

Methods a descriptive and cross-sectional study, carried out through a questionnaire using the Rome III criteria in 372 patients treated at the outpatient endocrinology clinic.

Results of 372 patients evaluated, the frequency of constipation found was 31.2% among diabetic patients. Females predominated in the sample (72.8%) as well as for the frequency of constipation (80.2%). The incidence of type II diabetes was 97.3% and it was observed that 80.2% of the sample was older than 50 years. One hundred and twelve patients with inadequate glycemic control (HgA1c ≥ 7) had an association with constipation.

Conclusion there was an increased frequency of constipation in patients with diabetes mellitus according to the Rome III criteria, in relation to the general population. The inadequate glycemic control in patients with diabetes mellitus increases the frequency of constipation and it is necessary to perform studies that allow the confirmation of this association to demonstrate this hypothesis.

1907-2020: more than one century of colonic mass movements in humans

Motility of the large bowel may be grossly subdivided in two types of contractile activity: low-amplitude single or cyclic propagated waves and high-amplitude propagated activity. The latter is mainly apt to shift relatively large amounts of colonic contents, and it is related to defecation. The main component of this propagated activity is represented by the radiologically identified mass movements that have a manometric equivalent known as high-amplitude propagated contractions (HAPC). The present article reviews origins and characterization of HAPC in the time course of colonic motility investigations, and correlates it with technological advancements in recent years, putting into perspective the future possible options to better detect and investigate these important physiological events.

The Altered Signaling on EFS-Induced Colon Contractility in Diabetic Rats

Diabetes mellitus affects the colonic motility developing gastrointestinal symptoms, such as constipation. The aim of the study was to examine the role of intracellular signaling pathways contributing to colonic dysmotility in diabetes mellitus. To generate diabetes mellitus, the rats were injected by a single high dose of streptozotocin (65 mg/kg) intraperitoneally. The proximal colons from both normal and diabetic rats were contracted by applying an electrical field stimulation with pulse voltage of 40 V in amplitude and pulse duration of 1 ms at frequencies of 1, 2, 4, and 6 Hz. The muscle strips from both normal rats and rats with diabetes mellitus were pretreated with different antagonists and inhibitors. Rats with diabetes mellitus had lower motility than the control group. There were significant differences in the percentage of inhibition of contraction between normal rats and rats with diabetes mellitus after the incubation of tetrodotoxin (neuronal blocker), atropine (muscarinic receptor antagonist), prazosin (α₁ adrenergic receptor antagonist), DPCPX (adenosine A1 receptor antagonist), verapamil (L-type Ca²⁺ channel blocker), U73122 (PLC inhibitor), ML-9 (MLCK inhibitor), udenafil (PDE₅ inhibitor), and methylene blue (guanylate cyclase inhibitor). The protein expression of p-MLC and PDE₅ were decreased in the diabetic group compared to the normal group. These results showed that the reduced colonic contractility resulted from the impaired neuronal conduction and decreased muscarinic receptor sensitivity, which resulted in decreased phosphorylation of MLC via MLCK, and cGMP activity through PDE₅.

Diabetic Gastroparesis

This review covers the epidemiology, pathophysiology, clinical features, diagnosis, and management of diabetic gastroparesis, and more broadly diabetic gastroenteropathy, which encompasses all the gastrointestinal manifestations of diabetes mellitus. Up to 50% of patients with type 1 and type 2 DM and suboptimal glycemic control have delayed gastric emptying (GE), which can be documented with scintigraphy, 13C breath tests, or a wireless motility capsule; the remainder have normal or rapid GE. Many patients with delayed GE are asymptomatic; others have dyspepsia (i.e., mild to moderate indigestion, with or without a mild delay in GE) or gastroparesis, which is a syndrome characterized by moderate to severe upper gastrointestinal symptoms and delayed GE that suggest, but are not accompanied by, gastric outlet obstruction. Gastroparesis can markedly impair quality of life, and up to 50% of patients have significant anxiety and/or depression. Often the distinction between dyspepsia and gastroparesis is based on clinical judgement rather than established criteria. Hyperglycemia, autonomic neuropathy, and enteric neuromuscular inflammation and injury are implicated in the pathogenesis of delayed GE. Alternatively, there are limited data to suggest that delayed GE may affect glycemic control. The management of diabetic gastroparesis is guided by the severity of symptoms, the magnitude of delayed GE, and the nutritional status. Initial options include dietary modifications, supplemental oral nutrition, and antiemetic and prokinetic medications. Patients with more severe symptoms may require a venting gastrostomy or jejunostomy and/or gastric electrical stimulation. Promising newer therapeutic approaches include ghrelin receptor agonists and selective 5-hydroxytryptamine receptor agonists.

Which Patient-Related Factors Determine Optimal Bowel Preparation?

PURPOSE OF REVIEW

Adequate bowel cleansing before colonoscopy is a simple concept but the high rate of inadequate or incomplete bowel cleanliness and its consequences have been the subject of many studies, guidelines, and meta-analysis. The complexity resides in all the factors surrounding preparation intake such as type and regimen of bowel preparation, diets, compliance, and also patient-related factors that all influence quality of the bowel preparation. The purpose of this review is to focus specifically on patient-related factors and their challenges. Patients with lower GI bleeding are excluded from this review.

RECENT FINDINGS

Patient factors that may be associated with a poor bowel preparation were searched for in the literature. With regard to patient's characteristics, higher age, male gender, and socio-economic status (lower income, Medicaid, and lower education) were all associated with higher rates of inadequate bowel preparation. Comorbidities such as inflammatory bowel disease (IBD), in-patients, body mass index (BMI), cirrhosis, constipation, and neurological condition as well as some pharmacotherapy were also associated with inadequate bowel preparation. Studies identifying predictive patient factors as well as those studying these patients in particular showed variability in the strength of the patient factor associations. Patients taking tricyclic antidepressant, narcotics, and those with neurological conditions were identified to have a stronger association with worse bowel cleanliness. Those can be implemented with the current recommendations of split-dosing. Identifying individual factors that can impact the quality of bowel cleanliness can be challenging. Some have been well-studied in the literature such as age, in-patient status, or constipation and others such as male gender or higher BMI have required more studies to clearly conclude on any possible association. In many studies, simple recommendations like walking 30 min during the preparation, and additional instructions or support have also been added to instructions to improve motility and compliance.

Efficacy and tolerability of various bowel preparations in diabetic patients: a randomized controlled trial

Background and study aims  Diabetes mellitus (DM) is an independent risk factor for poor bowel preparation prior to colonoscopy. Bisacodyl is a stimulant laxative that may mitigate colonic dysmotility associated with diabetes. We hypothesized that adding bisacodyl to split-dose bowel preparation (SDBP) would improve the quality of bowel preparation among patients with diabetes. Patients and methods  Adult outpatients aged 18 to 80 years undergoing colonoscopy were recruited. One hundred and eighty-six patients with diabetes were randomly assigned to 1 of 3 treatment arms: 1) conventional 4 L of polyethylene glycol electrolyte lavage solution (PEG-ELS; conventional bowel preparation [CBP]); 2) split-dose of 4 L PEG-ELS (split-dose bowel preparation [SDBP]); or 3) split-dose of 4 L PEG-ELS preceded by 10 mg of oral bisacodyl 10 (SDBP-B). The primary outcome measure was bowel cleansing as indicated by Boston Bowel Preparation Scale (BBPS) score. Endoscopists were blinded to the preparation used. Secondary outcome measures were safety and patient tolerability. Results  Of the 212 patients randomized, only 186 received assigned bowel preparation. There were no differences among the three study groups with regard to age, indication, duration of DM, insulin use, narcotic use, or presence of end-organ diabetic complications. There was a trend toward better bowel preparation quality among those receiving SDBP and SDBP-B compared to those receiving CBP, but the trend was not statistically significant  ≥ 6 BBPS; 67 % vs. 83 % vs. 75 %, P  = 0.1). In terms of safety and tolerability, there were no differences among the three groups. Conclusion  Adding bisacodyl to SDBP does not improve the quality of bowel preparation in patients with DM. Further efforts are needed to optimize colonoscopy bowel preparation in this population.

Implication of neurohormonal-coupled mechanisms of gastric emptying and pancreatic secretory function in diabetic gastroparesis

Recently, diabetic gastroparesis (DGP) has received much attention as its prevalence is increasing in a dramatic fashion and management of patients with DGP represents a challenge in the clinical practice due to the limited therapeutic options. DGP highlights an interrelationship between the gastric emptying and pancreatic secretory function that regulate a wide range of digestive and metabolic functions, respectively. It well documented that both gastric emptying and pancreatic secretion are under delicate control by multiple neurohormonal mechanisms including extrinsic parasympathetic pathways and gastrointestinal (GI) hormones. Interestingly, the latter released in response to various determinants that related to the rate and quality of gastric emptying. Others and we have provided strong evidence that the central autonomic nuclei send a dual output (excitatory and inhibitory) to the stomach and the pancreas in response to a variety of hormonal signals from the abdominal viscera. Most of these hormones released upon gastric emptying to provide feedback, and control this process and simultaneously regulate pancreatic secretion and postprandial glycemia. These findings emphasize an important link between gastric emptying and pancreatic secretion and its role in maintaining homeostatic processes within the GI tract. The present review deals with the neurohormonal-coupled mechanisms of gastric emptying and pancreatic secretory function that implicated in DGP and this provides new insights in our understanding of the pathophysiology of DGP. This also enhances the process of identifying potential therapeutic targets to treat DGP and limit the complications of current management practices.

Predictors of inadequate bowel preparation for colonoscopy: a systematic review and meta-analysis

The aim of this study was to investigate factors contributing to poor bowel preparation in patients undergoing colonoscopy procedures. We used a reproducible search strategy to identify studies, searching 10 medical databases, including PubMed, Ovid, Medline, and Cochrane Library Database for reports published between 2000 and 2016. Fully published studies, evaluating risk factors for inadequate bowel preparation, were included. Two reviewers independently scored the identified studies for methodology and abstracted pertinent data. Pooling was conducted with both fixed-effects and random-effects models; results were presented from the random effects model when heterogeneity was significant. Odds ratios (OR) estimates with 95% confidence interval were calculated. Heterogeneity was assessed by I statistics. Twenty-four studies with a total of 49 868 patients met the inclusion criteria. Age (OR: -1.20), male sex (OR: 0.85), inpatient status (OR: 0.57), diabetes mellitus (OR: 0.58), hypertension (OR: 0.58), cirrhosis (OR: 0.49), narcotic use (OR: 0.59), constipation (OR: 0.61), stroke (OR; 0.51), and tricyclic antidepressant (TCA) use (0.51), were associated with inadequate bowel preparation. In our sensitivity analysis comparing Western and Asian countries, we found that diabetes, cirrhosis, male sex, history of stroke and TCA use were stronger risk factors for inadequate bowel preparation in Western countries than in Asian countries. We also found that history of stroke, TCA use, and race were risk factors for inadequate bowel preparation in patients receiving conventional bowel preparation compared with those receiving split-dose bowel preparation. Multiple risk factors affect the quality of bowel preparation and specific risk factors can be intervened upon, in different populations, to optimize preparation.

Gastric Emptying Time, Esophageal pH-Impedance Parameters, Quality of Life, and Gastrointestinal Comorbidity in Obese Children and Adolescents

OBJECTIVES

To provide further evidence regarding the relationship between obesity and gastroesophageal reflux disease (GERD) in children, through the use of 13C-octanoic acid breath test for gastric emptying time (GET) assessment and esophageal multichannel intraluminal impedance pH-testing (MII-pH).

STUDY DESIGN

Obese children aged 4-17 years completed a questionnaire investigating reflux symptoms, the presence of functional gastrointestinal disorders, and quality of life. A subgroup of obese patients with and without GERD symptoms were asked to undergo 13C-octanoic acid breath test. Symptomatic patients were also required to undergo MII-pH. Age- and sex- matched asymptomatic nonobese children were enrolled as a comparison group.

RESULTS

Of 113 enrolled patients, 44 (38.9%) reported reflux symptoms; 22 of the 44 underwent MII-pH. Their mean reflux index was 14.6%, and their mean number of daily reflux episodes was 51.8. The mean T½ GET of symptomatic was 107.6 minutes vs 116.5 minutes in asymptomatic obese children. Healthy nonobese children had a mean T½ GET of 100.1 minutes. The mean GET of symptomatic obese patients having >70 daily reflux events was 121.8 vs 87.6 minutes of patients with <70 daily reflux events (P <.05). Both symptomatic and asymptomatic obese patients had a worse quality of life than nonobese (P = 0.003 and P = 0.0002, respectively); a narrow waist circumference was directly related to GET (P = 0.01).

CONCLUSIONS

A high percentage of obese children and adolescents experience GERD symptoms. GET was directly related to the narrow waist circumference of obese children with GERD and was significantly delayed in obese children with increased reflux events. Both symptomatic and asymptomatic obese patients had a worse quality of life compared with nonobese healthy patients.

Diabetes-induced mechanophysiological changes in the small intestine and colon

The disorders of gastrointestinal (GI) tract including intestine and colon are common in the patients with diabetes mellitus (DM). DM induced intestinal and colonic structural and biomechanical remodeling in animals and humans. The remodeling is closely related to motor-sensory abnormalities of the intestine and colon which are associated with the symptoms frequently encountered in patients with DM such as diarrhea and constipation. In this review, firstly we review DM-induced histomorphological and biomechanical remodeling of intestine and colon. Secondly we review motor-sensory dysfunction and how they relate to intestinal and colonic abnormalities. Finally the clinical consequences of DM-induced changes in the intestine and colon including diarrhea, constipation, gut microbiota change and colon cancer are discussed. The final goal is to increase the understanding of DM-induced changes in the gut and the subsequent clinical consequences in order to provide the clinicians with a better understanding of the GI disorders in diabetic patients and facilitates treatments tailored to these patients.

Impact of Resected Colon Site on Quality of Bowel Preparation in Patients Who Underwent Prior Colorectal Resection

BACKGROUND AND AIM

Various factors are known to be associated with quality of bowel preparation (QBP), but have rarely been investigated in patients with prior colorectal resection. The aim of this study was to investigate variables associated with bowel preparation in patients with prior colorectal resection.

MATERIALS AND METHODS

A total of 247 patients with prior colorectal resection and undergone surveillance colonoscopy were consecutively chosen. One clinician performed endoscopy for all patients. QBP was rated using Aronchick grade and was categorized as either satisfactory (Aronchick grades, 1 to 3) or unsatisfactory (Aronchick grades, 4 and 5). Factors associated with QBP were analyzed.

RESULTS

Unsatisfactory bowel preparation was detected in 49 patients (19.8%). There was no difference in QBP on the basis of sex, age, body mass index, hypertension history, diabetes mellitus history, smoking habits, time after surgery, resected colon length, or bowel preparation method. Operation method was marginally associated with QBP (P=0.056). When we dichotomized patients into right-side colon preservation or not, the right colon preservation group showed a significant association with poor QBP on univariate (22.3% vs. 7.5%, P=0.028) and multivariate analysis (odds ratio, 3.6; 95% confidence interval, 1.0-12.3; P=0.038).

CONCLUSION

Patients with a preserved right colon were associated with poor bowel preparations compared with patients who underwent right-side colon resection. When preparing patients with history of colorectal resection for colonoscopy, these differences should be considered for better bowel preparation.

Tangshen Formula Attenuates Colonic Structure Remodeling in Type 2 Diabetic Rats

Aim. This study investigated the effect and mechanism of the Chinese herbal medicine Tangshen Formula (TSF) on GI structure remodeling in the rat model of diabetes. Methods. Type 2 diabetic rats were used. Wet weight per unit length, layer thicknesses, levels of collagens I and III, nuclear factor kappa B (NF-κB), interferon-γ (IFN-γ), interleukin-6 (IL-6), transforming growth factor-β1 (TGF-β1), and Smad2/3 expression in the rat colon were measured. Results. Compared with the control group animals, wet weight and layer thicknesses of the colon increased, and expressions of collagens I and III, NF-κB, IFN-γ, IL-6, TGF-β1, and Smad2/3 increased significantly in the diabetic animals. TSF inhibited increase in colonic wet weight and layer thicknesses, downregulated expressions of collagens I and III in the mucosal layer, and downregulated expressions of NF-κB, IFN-γ, IL-6, TGF-β1, and Smad2/3 in the colon wall. Furthermore, level of expression of NF-κB was associated with those of TGF-β1 and Smad2/3. Expression of TGF-β1 was associated with the most histomorphometric parameters including colonic weight, mucosal and muscle thicknesses, and levels of collagens I and III in mucosal layer. Conclusion. TSF appears to attenuate colonic structure remodeling in type 2 diabetic rats through inhibiting the overactivated pathway of NF-κB, thus reducing expressions of TGF-β1.

Diabetics on Narcotics Are Less Likely to Achieve Excellent Bowel Preparation Than Are Patients with Either Condition

BACKGROUND

Diabetes and chronic narcotic use negatively affect the quality of bowel preparation before colonoscopy.

AIM

To investigate whether narcotic use and diabetes have an additive negative impact on bowel preparation.

PATIENTS AND METHODS

We performed a retrospective study of 2841 patients (mean age 61 ± 10.2; 94% male) who received outpatient colonoscopies at our Veterans Affairs Medical Center between June 2012 and December 2014. We collected information related to demographics, body mass index, indications, and medical/surgical history (diabetes mellitus, stroke, cirrhosis, dementia, constipation, hypothyroidism, and use of narcotics or antidepressants/anxiolytics for more than three months). Patients were classified into four groups: (1) diabetics on narcotics, (2) diabetics only, (3) on narcotics only, and (4) neither diabetic nor using narcotics. Quality of the bowel preparation was scored using the Boston Bowel Preparation Scale (BBPS) and categorized as either excellent (BBPS ≥7, with no individual segment scoring <2) or not excellent (BBPS <7). Multivariate logistic regression analysis was performed to identify the combined impact of narcotic use and diabetes on bowel preparation.

RESULTS

Bowel preparation quality was excellent in 49%. Thirty-eight percent of patients with diabetes who were using narcotics (adjusted OR 0.6, CI [0.4, 0.8]) achieved excellent bowel preparation compared with 44% (adjusted OR 0.7, CI [0.6, 0.9]) of patients on narcotics only, 48% (adjusted OR 0.8, CI [0.7, 0.9]) of diabetics only, and 54% of patients with neither condition.

CONCLUSION

Concomitant narcotic use and diabetes have a compounding effect on the quality of bowel preparation prior to colonoscopy.

Inadequate Bowel Cleansing Efficacy of Split-dose Polyethylene Glycol for Colonoscopy in Type 2 Diabetic Patients: A Prospective and Blinded Study

BACKGROUND/AIMS

Split-dose polyethylene glycol (PEG) is considered a standard bowel preparation regimen for colonoscopy in the general population. However, it is not clear whether the regimen is optimal for colonoscopy in diabetic patients. The aim of this study was to compare the efficacy and tolerability of split-dose PEG for diabetic versus nondiabetic patients.

METHODS

This is a single-center, prospective, investigator-blinded study. A total of 55 consecutive nondiabetic and 50 diabetic patients ingested 2 L PEG solution on the day before the procedure and then 2 L of the solution on the day of colonoscopy. The quality of bowel preparation was graded using the Ottawa scale.

RESULTS

There was a significant difference in bowel preparation quality, with a worse preparation except for mid colon in diabetic group (total score: 7.06±1.69 vs. 5.54±1.97, P<0.001; right colon: 2.28±0.57 vs. 1.81±0.72, P<0.001; mid colon: 1.70±0.54 vs. 1.56±0.66, P=0.253; rectosigmoid colon: 1.70±0.76 vs. 1.14±0.62, P<0.001; fluid volume: 1.38±0.53 vs. 1.01±0.59, P=0.001). About 70% of nondiabetic patients had an adequate preparation compared with only 40% of diabetic patients (P=0.003). Diabetic group had longer cecal intubation time (6.4±3.6 vs. 4.5±2.4, P=0.002) and total procedure time (22.1±7.6 vs. 18.1±8.5, P=0.015). Compliance and adverse events were not significantly different. In diabetic group, inadequate bowel preparation had a significant association with higher fasting plasma glucose (136.9±21.8 vs. 121.8±19.4 mg/dL, P=0.016).

CONCLUSIONS

Diabetic patients had a worse preparation quality and longer cecal intubation and total procedure time compared with nondiabetic patients. These data suggest that split-dose PEG preparation regimen is not sufficient for optimal bowel preparation in diabetic patients undergoing colonoscopy.

Influence of gastric emptying on the control of postprandial glycemia: physiology and therapeutic implications

The maintenance of glucose homeostasis is complex and involves, besides the secretion and action of insulin and glucagon, a hormonal and neural mechanism, regulating the rate of gastric emptying. This mechanism depends on extrinsic and intrinsic factors. Glucagon-like peptide-1 secretion regulates the speed of gastric emptying, contributing to the control of postprandial glycemia. The pharmacodynamic characteristics of various agents of this class can explain the effects more relevant in fasting or postprandial glucose, and can thus guide the individualized treatment, according to the clinical and pathophysiological features of each patient.

Food: the forgotten factor in the irritable bowel syndrome

After years of inattention, there is a growing body of evidence to suggest that dietary constituents at least exacerbate symptoms and perhaps contribute to the pathogenesis of the irritable bowel syndrome (IBS). Although patients with IBS self-report food allergies more often than the general population, the evidence suggests that true food allergies are relatively uncommon. Less clearly defined food intolerances may be an important contributor to symptoms in IBS patients. This article reviews the literature supporting a causal link between food and the symptoms of IBS as well as the evidence supporting dietary interventions as a means of managing IBS symptoms.

Efficacy and safety of sodium phosphate for colon cleansing in type 2 diabetes mellitus

OBJECTIVES

The need for colonoscopy is common among diabetic patients. However, there are no standards per se for bowel preparation in patients with type 2 diabetes. In this study, we evaluated the efficacy, safety, and tolerability of sodium phosphate (NaP), and the quality of bowel cleansing in relation to glycemic control and late complications.

METHODS

A total of 50 consecutive type 2 diabetic patients and 50 non-diabetic patients underwent bowel preparation by NaP. Fasting blood glucose, sodium (Na), potassium (K), calcium (Ca), phosphorus (P), magnesium, and creatinine levels were measured on the procedure day. Patients were given a tolerability questionnaire regarding symptoms.

RESULTS

With regard to bowel preparation quality, optimal bowel cleansing was achieved in 35 (70%) diabetic and 47 (94%) non-diabetic patients (P = 0.002). Abdominal pain or discomfort during and an hour after the procedure was similar in both groups (P >0.05). The changes in Na, K, Ca, P and creatinine levels after NaP use did not reach statistical significance between the groups (P >0.05). In the diabetic patients, there was a significant correlation between the quality of bowel cleansing and mean age, duration of diabetes mellitus, level of hemoglobin A1c (HbA1c), fasting blood glucose level, and diabetic late complications (P <0.05).

CONCLUSION

These data suggest that NaP is safe and tolerable in diabetic patients, but the quality of bowel cleansing is worse than in non-diabetic patients. These observations support the concept that the quality of bowel cleansing in those with type 2 diabetes is closely related to the duration and regulation of the disease and the presence of late complications.

Colonic elongation inhibits pellet propulsion and migrating motor complexes in the murine large bowel

The colonic migrating motor complex (CMMC) is a rhythmically occurring neurally mediated motor pattern. Although the CMMC spontaneously propagates along an empty colon it is responsible for faecal pellet propulsion in the murine large bowel. Unlike the peristaltic reflex, the CMMC is an 'all or none' event that appears to be dependent upon Dogiel Type II/AH neurons for its regenerative slow propagation down the colon. A reduction in the amplitude of CMMCs or an elongated colon have both been thought to underlie slow transit constipation, although whether these phenomena are related has not been considered. In this study we examined the mechanisms by which colonic elongation might affect the CMMC using video imaging of the colon, tension and electrophysiological recordings from the muscle and Ca(2+) imaging of myenteric neurons. As faecal pellets were expelled from the murine colon, it shortened by up to 29%. Elongation of the colon resulted in a linear reduction in the velocity of a faecal pellet and the amplitude of spontaneous CMMCs. Elongation of the oral end of a colonic segment reduced the amplitude of CMMCs, whereas elongation of the anal end of the colon evoked a premature CMMC, and caused the majority of CMMCs to propagate in an anal to oral direction. Dogiel Type II/AH sensory neurons and most other myenteric neurons responded to oral elongation with reduced amplitude and frequency of spontaneous Ca(2+) transients, whereas anal elongation increased their amplitude and frequency in most neurons. The inhibitory effects of colonic elongation were reduced by blocking nitric oxide (NO) production with l-NA (100 mum) and soluble guanylate cyclase with 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 mum); whereas, l-arginine (1-2 mm) enhanced the inhibitory effects of colonic elongation. In conclusion, polarized neural reflexes can be triggered by longitudinal stretch. The dominant effect of elongation is to reduce CMMCs primarily by inhibiting Dogiel Type II/AH neurons, thus facilitating colonic accommodation and slow transit.

Electroacupuncture improves impaired gastric motility and slow waves induced by rectal distension in dogs

Rectal distension (RD) is known to induce upper gastrointestinal (GI) symptoms. The aim of this study was to investigate the effects and underlying mechanisms of RD on gastric slow waves (GSW) and motor activity and furthermore to investigate the effects and mechanisms of electroacupuncture (EA) on GSW and motor activity. Eight female hound dogs chronically implanted with gastric serosal electrodes and a gastric fistula were studied in six separate sessions. Antral motility, GSW, heart rate variability, and rectal pressure were evaluated for the above purposes. 1) RD at a volume of 120 ml suppressed antral motility significantly. Guanethidine blocked the inhibitory effect of RD. EA at ST36 was able to restore the suppressed antral contractions induced by RD (16.6+/-1.7 vs. 8.0+/-1.4, P<0.001). Naloxone partially blocked the effect of EA on antral contractions. 2) RD reduced the percentage of normal GSW from 98.8+/-0.8% at baseline to 76.1+/-8.6% (P<0.05) that was increased to 91.8+/-3.0% with EA. The effects of EA on the GSW were nullified by the presence of naloxone. 3) EA did not show any significant effect on rectal pressure, suggesting that the ameliorating effects of EA on RD-induced impaired gastric motility were not due to a decrease in rectal pressure. 4) EA increased the vagal activity suppressed by RD. In conclusion, RD inhibits postprandial gastric motility and impairs GSW in dogs, and the inhibitory effects are mediated via the adrenergic pathways. EA at ST36 is able to restore the RD-induced impaired GSW and motor activities, possibly by enhancing vagal activity, and is partially mediated via the opioid pathway. EA may have therapeutic potential for functional gastrointestinal disorders.

Gastrointestinal motility in acute illness

Critical illness affects gastrointestinal motility - not only as a primary problem, which brings the patient to the intensive care unit (ICU), but also as a complication consecutive to the ICU stay. Motility disturbances may result from impaired function of gastrointestinal muscle, pacemaker cell function and nerve activity. The most important neural control system is the enteric nervous system that contains the largest collection of neurons (10(8) cells) outside the central nervous system. Through its organization it can operate independently of the brain and generate motility patterns according to need: a postprandial motility pattern starting after food intake, and an interdigestive motility pattern starting several hours after a meal. Undisturbed intestinal motility depends critically on a balanced interaction between inhibition and excitation, and a disturbance in this balance leads to severe derangements of intestinal motility. These motility disturbances differ in clinical appearance and location but can affect all parts of the gastrointestinal tract. This review focuses on select motility disturbances such as gastroparesis, postoperative ileus, and Ogilvie's syndrome. Generally effective methods to treat these conditions are given. Finally, we focus on special management options to prevent such motility disturbances or to reduce their severity.

Glycemic effect of administration of epinephrine-containing local anaesthesia in patients undergoing dental extraction, a comparison between healthy and diabetic patients

OBJECTIVES

To compare the effect of administration of epinephrine (in the dental local anesthetic solution) on blood glucose concentration in healthy and diabetic dental patients after extraction. To determine if there is any correlation between blood glucose level changes and the number of carpules injected, number of teeth extracted and the gender of the patient.

MATERIALS AND METHOD

An open study of 60 patients (30 healthy and 30 diabetics) visiting the Oral Surgery clinic of Ajman University of Science and Technology. A drop of blood was taken from the tip of the patient's finger and placed on a glucometer strip to determine the pre-operative blood glucose level. Dental local anaesthesia (1.8 ml carpule each) containing 1:80,000 epinephrine was injected either through infiltration or block. Extraction was carried out atraumatically and 10 minutes post-extraction the glucose measurement was taken.

RESULTS

The difference in the blood glucose levels pre- and post operatively were not significantly different (p > 0.05) when a comparison was made between the healthy and diabetic groups. Comparison of glucose changes in diabetics who had taken their hypoglycaemic medication and those who had not, showed a significant difference (p < 0.05). Statistical analysis showed no correlation between the blood glucose level changes and the number of carpules used, number of teeth extracted and gender.

CONCLUSION

Dental local anaesthetic solution containing epinephrine is safe to use in all healthy and diabetic patients (irrespective of their gender), excepting those diabetics who have not taken their pre-operative hypoglycaemic medication. There is no relation between the post-extraction glucose changes and the number of carpules used, number of teeth extracted or gender.

Advances in mechanisms of postsurgical gastroparesis syndrome and its diagnosis and treatment

Postsurgical gastroparesis syndrome (PGS) is a complex disorder characterized by post-prandial nausea and vomiting, and gastric atony in the absence of mechanical gastric outlet obstruction, and is often caused by operation at the upper abdomen, especially by gastric or pancreatic resection, and sometimes also by operation at the lower abdomen, such as gynecological or obstetrical procedures. PGS occurs easily with oral intake of food or change in the form of food after operation. These symptoms can be disabling and often fail to be alleviated by drug therapy, and gastric reoperations usually prove unsuccessful. The cause of PGS has not been identified, nor has its mechanism quite been clarified. PGS after gastrectomy has been reported in many previous studies, with an incidence of approximately 0.4-5.0%. PGS is also a frequent complication of pylorus-preserving pancreatoduodenectomy (PPPD), and the complication occurs in the early postoperative period in 20-50% of patients. PGS caused by pancreatic cancer cryoablation (PCC) has been reported about in 50-70% of patients. Therefore, PGS has a complex etiology and might be caused by multiple factors and mechanisms. The frequency of this complication varies directly with the type and number of gastric operations performed. The loss of gastric parasympathetic control resulting from vagotomy contributes to PGS via several mechanisms. It has been reported that the interstitial cells of Cajal (ICC) may play a role in the pathogenesis of PGS. Recent studies in animal models of diabetes suggest specific molecular changes in the enteric nervous system may result in delayed gastric emptying. The absence of the duodenum, and hence gastric phase III, may be a cause of gastric stasis. It was thought that PGS after PPPD might be attributable, at least in part, to delayed recovery of gastric phase III, due to lowered concentrations of plasma motilin after resection of the duodenum. The damage to ICC might play a role in the pathogenesis of PGS after PCC, for which multiple factors are possibly responsible, including ischemic and neural injury to the antropyloric muscle and the duodenum after freezing of the pancreatoduodenal regions or reduction of circulating levels of motilin. As the treatment of gastroparesis is far from ideal, non-conventional approaches and non-standard medications might be of use. Multiple treatments are better than single treatment. This article reviews almost all the papers related to PGS from various journals published in English and Chinese in recent years in order to facilitate a better understanding of PGS.

Modulation of intestinal gas dynamics in healthy human volunteers by the 5-HT receptor agonist tegaserod

OBJECTIVES

Bloating in irritable bowel syndrome (IBS) may result from impaired intestinal gas transit and is reduced by the 5-HT4 agonist tegaserod. Abnormal serotonergic function underlies many IBS symptoms, but the role of 5-HT4 pathways in regulating gas dynamics under healthy conditions is unexplored. We hypothesized that 5-HT4 activation by tegaserod stimulates gas transit in healthy individuals.

METHODS

Sixteen normal volunteers underwent jejunal perfusion of gas mixtures (88% N2, 5.5% O2, 6.5% CO2) at 11.2 mL/min x 3 h under control conditions and 3 h after oral tegaserod 6 mg on separate days. Gas collected from an intrarectal catheter was quantified using a barostat.

RESULTS

Under control conditions, gas evacuation after a lag period (1,959 +/- 428 s) was predominantly pulsatile with expulsion of 1,984 +/- 90 mL. A mean of 29 +/- 2 boluses with volumes of 72 +/- 5 mL were expelled. In 10 subjects with physiologic degrees of gas retention in control studies (248 +/- 73 mL), tegaserod increased expulsion from 1,768 +/- 73 to 1,973 +/- 37 mL and decreased retention to 43 +/- 37 mL (p < 0.05). Total volumes expelled as boluses were greater after tegaserod (1,708 +/- 73 vs 1,846 +/- 59 mL, p < 0.05) from increased bolus numbers in four subjects and increased bolus volumes in seven. Nonpulsatile continuous flow tended to increase with tegaserod (43 +/- 7 vs 126 +/- 43 mL, p= 0.10). Tegaserod did not increase evacuation in individuals without physiologic gas retention.

CONCLUSIONS

The 5-HT4 agonist tegaserod promotes evacuation of jejunally perfused gas mixtures in healthy humans. These findings provide the foundation for future investigations into use of 5-HT4 agonists in conditions of pathologic gas retention.

Low-dose lactulose produces a tonic contraction in the human colon

Lactulose (10-20 g day(-1)) is used to treat constipation. At this therapeutic dose, its effects on colonic motility remain unknown. Twenty-two healthy subjects swallowed a probe with an infusion catheter, six perfused catheters and a balloon connected to a barostat. Colonic phasic and tonic motor activity was recorded in fasting state. In group 1, four volunteers ingested 15 g lactulose and motility was recorded for 5 h after entry of lactulose into the caecum; in group 2, motility was recorded during (3 h) and 2 h after intracolonic infusion of isoosmotic and isovolumetric solutions containing sodium chloride alone (n = 9) or with 15 g lactulose (n = 9). In a last group of volunteers, isotopic colonic transit after ingestion of lactulose (10 g,n = 9) was assessed and compared with a control group (n = 17). Ingestion or intracolonic infusion of 15 g lactulose significantly decreased barostat bag volume (maximal decrease: 45 +/- 12% and 35 +/- 9% of basal value respectively). Phasic contractions remained unchanged. Tonic and phasic motility was unchanged by the isotonic and isovolumetric infusion of saline. Ingestion of lactulose significantly accelerated isotopic colonic transit time compared with the control group. We conclude that in healthy humans, 10-15 g ingestion or intracaecal infusion of lactulose produces a prolonged tonic contraction that may be involved in the laxative effect of lactulose.

Attenuation of the colorectal tonic reflex in female patients with irritable bowel syndrome

Alterations in normal intestinointestinal reflexes may be important contributors to the pathophysiology of irritable bowel syndrome (IBS). Our aims were to compare the rectal tonic responses to colonic distension in female IBS patients with predominant constipation (IBS-C) and with predominant diarrhea (IBS-D) to those in healthy females, both fasting and postprandially. Using a dual barostat assembly, 2-min colonic phasic distensions were performed during fasting and postprandially. Rectal tone was recorded before, during, and after the phasic distension. Colonic compliance and colonic sensitivity in response to the distension were also evaluated fasting and postprandially. Eight IBS-C patients, 8 IBS-D patients, and 8 age- and sex-matched healthy subjects (group N) participated. The fasting increments in rectal tone in response to colonic distension in both IBS-C (rectal balloon volume change -4.6 +/- 6.1 ml) and IBS-D (-7.9 +/- 4.9 ml) were significantly reduced compared with group N (-34 +/- 9.7 ml, P = 0.01). Similar findings were observed postprandially (P = 0.02). When adjusted for the colonic compliance of individual subjects, the degree of attenuation in the rectal tonic response in IBS compared with group N was maintained (fasting P = 0.007; postprandial P = 0.03). When adjusted for colonic sensitivity there was a trend for the attenuation in the rectal tonic response in IBS patients compared with group N to be maintained (fasting P = 0.07, postprandial P = 0.08). IBS patients display a definite attenuation of the normal increase in rectal tone in response to colonic distension (colorectal reflex), fasting and postprandially. Alterations in colonic compliance and sensitivity in IBS are not likely to contribute to such attenuation.

Intussusception as a gastrointestinal complication of diabetes: case report and literature review

This is the first reported case of intussusception in a patient with type 1 diabetes mellitus complicated by gastroparesis and autonomic neuropathy. Literature on the reported cases of intussusception in patients with diabetes, its aetiopathology and possible association with gastroparesis has been systematically reviewed following a Medline database search (1951 to June 2003) Intussusception should be considered in the differential diagnosis of gastrointestinal symptoms in diabetic patients presenting with hyperglycaemia.

Increased prevalence of constipation and fecal soiling in a population of obese children

To determine the prevalence of constipation and fecal soiling in obese children, we asked standardized questions during the initial visit to the obesity clinic. In 80 obese children, 23% met the criteria for constipation, and 15% reported fecal soiling. Constipation and soiling are more prevalent in obese children.

Effect of hyperglycemia on triggering of transient lower esophageal sphincter relaxations

Acute changes in blood glucose concentration have major effects on gastrointestinal motor function. Patients with diabetes mellitus have an increased prevalence of gastroesophageal reflux. Transient lower esophageal sphincter (LES) relaxation (TLESR) is the most common sphincter mechanism underlying reflux. The aim of this study was to investigate the effect of acute hyperglycemia on triggering TLESRs evoked by gastric distension in healthy volunteers. TLESRs were stimulated by pressure-controlled and volume-controlled (500 ml) gastric distension using an electronic barostat and performed on separate days. On each day, esophageal manometry was performed in the sitting position during gastric distension for 1 h under euglycemia (5 mM), and either marked hyperglycemia (15 mM) or physiological hyperglycemia (8 mM) in randomized order was maintained by a glucose clamp. Marked hyperglycemia doubled the rate of TLESRs in response to both pressure-controlled [5 (3-10.5, median or interquartile range) to 10 (9.5-14.5) per hour, P < 0.02] and volume-controlled [4 (2.5-7.5) to 10.5 (7-12.5) per hour, P < 0.02] gastric distension but had no effect on basal LES pressure. Physiological hyperglycemia had no effect on the triggering of TLESRs or basal LES pressure. In healthy human subjects, marked hyperglycemia increases the rate of TLESRs. Increase in the rate of TLESRs is independent of proximal gastric wall tension. Mechanisms underlying the effect remain to be determined. Hyperglycemia may be an important factor contributing to the increased esophageal acid exposure in patients with diabetes mellitus.

Effects of acute hyperglycaemia on anorectal motor and sensory function in diabetes mellitus

AIMS

To determine the effects of acute hyperglycaemia on anorectal motor and sensory function in patients with diabetes mellitus.

METHODS

In eight patients with Type 1, and 10 patients with Type 2 diabetes anorectal motility and sensation were evaluated on separate days while the blood glucose concentration was stabilized at either 5 mmol/l or 12 mmol/l using a glucose clamp technique. Eight healthy subjects were studied under euglycaemic conditions. Anorectal motor and sensory function was evaluated using a sleeve/sidehole catheter, incorporating a barostat bag.

RESULTS

In diabetic subjects hyperglycaemia was associated with reductions in maximal (P<0.05) and plateau (P<0.05) anal squeeze pressures and the rectal pressure/volume relationship (compliance) during barostat distension (P<0.01). Hyperglycaemia had no effect on the perception of rectal distension. Apart from a reduction in rectal compliance (P<0.01) and a trend (P=0.06) for an increased number of spontaneous anal sphincter relaxations, there were no differences between the patients studied during euglycaemia when compared with healthy subjects.

CONCLUSIONS

In patients with diabetes, acute hyperglycaemia inhibits external anal sphincter function and decreases rectal compliance, potentially increasing the risk of faecal incontinence.

Reflex control of intestinal gas dynamics and tolerance in humans

Intestinal transit of gas is normally adapted to the luminal gas load, but in some patients impaired transit may lead to gas retention and symptoms. We hypothesized that intestinal gas transit is regulated by reflex mechanisms released by segmental distension at various gut levels. In 24 healthy subjects, we measured gas evacuation and perception of jejunal gas infusion (12 ml/min) during simultaneous infusion of duodenal lipids mimicking the postprandial caloric load (Intralipid, 1 kcal/min). We evaluated the effects of proximal (duodenal) distension (n = 8), distal (rectal) distension (n = 8), and sham distension, as control (n = 8). Duodenal lipid infusion produced gas retention (366 +/- 106 ml) with low abdominal perception (1.5 +/- 0.8 score). Distension of either the duodenum or rectum during lipid infusion expedited gas transit and prevented retention (-120 +/- 164 and -124 +/- 162 ml retention, respectively; P < 0.05 vs. control). However, the tolerance to the intestinal gas load differed markedly, depending on the site of distension; perception remained low during rectal distension (2.6 +/- 0.7 score; not significant vs. control) but increased during duodenal distension (4.4 +/- 0.7 score; P < 0.05 vs. control). We conclude that focal gut distension, either at proximal or distal sites, accelerates gas transit, but the symptomatic response depends on the site of stimulation.

Autonomic neuropathy and gastrointestinal motility disorders in children and adolescents with type 1 diabetes mellitus

INTRODUCTION

There is little information on the gastrointestinal motility abnormalities and autonomic neuropathy of children with gastrointestinal symptoms and type 1 diabetes mellitus (T1DM).

METHODS

The authors studied 33 consecutive patients (mean age, 15.3 years; 13 males) with T1DM (median duration, 7.7 years) attending the outpatient clinic because of chronic dyspepsia (CD; n = 14), or chronic constipation (CC; n = 19), and 48 consecutive non-T1DM patients (mean age, 13.7 years; 18 males), who presented with similar symptoms (18 with CD; 30 with CC). Fasting serum motilin concentrations and cardiovascular autonomic function tests (CAFT) were assessed and compared with those of age- and gender-matched healthy control subjects. Gastric emptying half time (GE t1/2) of a solid meal and mouth-to-anus transit time (MATT) were measured in patients with CD and CC, respectively.

RESULTS

CAFT was comparable between patients with T1DM and healthy control subjects. GE t1/2 and MATT were not different between T1DM patients and non-T1DM patients with CD and CC, respectively. However, a marginally significant positive correlation was found in the patients with T1DM between GE t1/2 and blood glucose concentrations (R = 0.54; P = 0.08). In addition, serum motilin concentrations were significantly lower in patients with T1DM compared with healthy control subjects (P < 0.0005), and in patients with T1DM and higher serum glucose concentrations compared with those with lower serum glucose concentrations (P = 0.03).

CONCLUSION

Autonomic neuropathy is not an etiological factor of gastrointestinal symptoms in children and adolescents with diabetes. Mild or moderate hyperglycemia does not affect gastrointestinal motility.

Prevalence of delayed gastric emptying in diabetic patients and relationship to dyspeptic symptoms: a prospective study in unselected diabetic patients

OBJECTIVE

Data on the prevalence of abnormal gastric emptying in diabetic patients are still lacking. The relation between gastric emptying and dyspeptic symptoms assessed during gastric emptying measurement has not yet been investigated. The aim was to investigate the prevalence of delayed gastric emptying in a large cohort of unselected diabetic patients and to investigate the relation between gastric emptying and gastrointestinal sensations experienced in the 2 weeks before and during the test meal, prospectively.

RESEARCH DESIGN AND METHODS

Gastric emptying was evaluated in 186 patients (106 with type 1 diabetes, mean duration of diabetes 11.6 +/- 11.3 years) using 100 mg (13)C-enriched octanoic acid added to a solid meal.

RESULTS

Gastric emptying was significantly slower in the diabetic subjects than in the healthy volunteers (T(50): 99.5 +/- 35.4 vs. 76.8 +/- 21.4 min, P < 0.003; Ret(120 min): 30.6 +/- 17.2 vs. 20.4 +/- 9.7%, P < 0.006). Delayed gastric emptying was observed in 51 (28%) diabetic subjects. The sensations experienced in the 2 weeks before the test were weakly correlated with the sensation scored during the gastric emptying test. Sensations assessed during the gastric emptying test did predict gastric emptying to some extent (r = 0.46, P < 0.0001), whereas sensations experienced in the previous 2 weeks did not.

CONCLUSIONS

This prospective study shows that delayed gastric emptying can be observed in 28% of unselected patients with diabetes. Upper gastrointestinal sensations scored during the gastric emptying tests do predict the rate of gastric emptying to some extent and sensation experienced during daily life does not.

Current concepts in diabetic gastroparesis

Diabetic gastroparesis is a common and debilitating condition affecting millions of patients with diabetes mellitus worldwide. Although gastroparesis in diabetes has been known clinically for more than 50 years, treatment options remain very limited. Until recently, the scientific literature has offered few clues regarding the precise aetiology of gastric dysfunction in diabetes.Up to 50% of patients with diabetes may experience postprandial abdominal pain, nausea, vomiting and bloating secondary to gastric dysfunction. There is no clear association between length of disease and the onset of delayed gastric emptying. Gastroparesis affects both type 1 (insulin dependent) and type 2 (non- insulin dependent) forms of diabetes. Diagnosis requires identifying the proper symptom complex, while excluding other entities (peptic ulcer disease, rheumatological diseases, medication effects). The diagnosis of gastroparesis may be confirmed by demonstrating gastric emptying delay during a 4-hour scintigraphic study. Treatment options are limited and rely on dietary modifications, judicious use of available pharmacological agents, and occasionally surgical or endoscopic placement of gastrostomies or jejunostomies. Gastric pacing offers promise for patients with medically refractory gastroparesis but awaits further investigation. Current pharmacological agents for treating gastroparesis include metoclopramide, erythromycin, cisapride (only available via a company-sponsored programme) and domperidone (not US FDA approved). All of these drugs act as promotility agents that increase the number or the intensity of gastric contractions. These medications are not uniformly effective and all have adverse effects that limit their use. Cisapride has been removed from the open market as a result of over 200 reported cases of cardiac toxicity attributed to its use. Unfortunately, there is a paucity of clinical studies that clearly define the efficacy of these agents in diabetic gastroparesis and there are no studies that compare these drugs to each other. The molecular pathophysiology of diabetic gastroparesis is unknown, limiting the development of rational therapies. New studies, primarily in animals, point to a defect in the enteric nervous system as a major molecular cause of abnormal gastric motility in diabetes. This defect is characterised by a loss of nitric oxide signals from nerves to muscles in the gut resulting in delayed gastric emptying. Novel therapies designed to augment nitric oxide signalling are being studied.

Current concepts in diabetic gastroparesis

Diabetic gastroparesis is a common and debilitating condition affecting millions of patients with diabetes mellitus worldwide. Although gastroparesis in diabetes has been known clinically for more than 50 years, treatment options remain very limited. Until recently, the scientific literature has offered few clues regarding the precise aetiology of gastric dysfunction in diabetes.Up to 50% of patients with diabetes may experience postprandial abdominal pain, nausea, vomiting and bloating secondary to gastric dysfunction. There is no clear association between length of disease and the onset of delayed gastric emptying. Gastroparesis affects both type 1 (insulin dependent) and type 2 (non- insulin dependent) forms of diabetes. Diagnosis requires identifying the proper symptom complex, while excluding other entities (peptic ulcer disease, rheumatological diseases, medication effects). The diagnosis of gastroparesis may be confirmed by demonstrating gastric emptying delay during a 4-hour scintigraphic study. Treatment options are limited and rely on dietary modifications, judicious use of available pharmacological agents, and occasionally surgical or endoscopic placement of gastrostomies or jejunostomies. Gastric pacing offers promise for patients with medically refractory gastroparesis but awaits further investigation. Current pharmacological agents for treating gastroparesis include metoclopramide, erythromycin, cisapride (only available via a company-sponsored programme) and domperidone (not US FDA approved). All of these drugs act as promotility agents that increase the number or the intensity of gastric contractions. These medications are not uniformly effective and all have adverse effects that limit their use. Cisapride has been removed from the open market as a result of over 200 reported cases of cardiac toxicity attributed to its use. Unfortunately, there is a paucity of clinical studies that clearly define the efficacy of these agents in diabetic gastroparesis and there are no studies that compare these drugs to each other. The molecular pathophysiology of diabetic gastroparesis is unknown, limiting the development of rational therapies. New studies, primarily in animals, point to a defect in the enteric nervous system as a major molecular cause of abnormal gastric motility in diabetes. This defect is characterised by a loss of nitric oxide signals from nerves to muscles in the gut resulting in delayed gastric emptying. Novel therapies designed to augment nitric oxide signalling are being studied.

Manometric techniques for the evaluation of colonic motor activity: current status

Colonic motility disorders are common conditions. However, our understanding of normal, and, consequently, pathological motor function of the colon remains limited, mainly due to the relative inaccessibility of this organ for study. Investigation of colonic motility may encompass one or more of the four separate components (myoelectric activity, phasic and tonic contractile activity and movement of intraluminal content) using electrophysiological, manometric or transit studies. Although transit studies provide the best 'functional' appreciation of colonic motor activity, and are the only techniques used in contemporary clinical practice, manometric methods are becoming increasingly popular, as they allow a direct study of colonic contractile activity over prolonged periods. To date, the majority of studies have been limited to the pelvic colon by a retrograde (per rectal) approach; however, recent technological advances have facilitated 'pan-colonic' investigation. This review concentrates on manometry of the human colon proximal to the sigmoid, and includes evaluation of both phasic and tonic motor activity, by utilization of perfused-tube and solid-state manometric catheters, and also the electronic barostat. Methodological techniques, experimental protocols and the analysis and interpretation of recorded data are critically explored, and a contemporary classification of colonic contractile activities is presented.

Diagnosis and treatment of chronic gastroparesis and chronic intestinal pseudo-obstruction

Chronic gastroparesis and CIP are debilitating disorders that are difficult to treat with currently available therapies. Failure of proper migration and differentiation of enteric neurons or ICC can result from specific genetic mutations and lead to phenotypes of CIP with or without concomitant gastroparesis. Intestinal dysfunction in diabetes may reflect a depletion of NO production (and perhaps other neurotransmitters or modulators), which is manifest as a syndrome of gastroparesis, diarrhea, or constipation in individual patients. As the key molecular changes underlying these disorders are defined, clinicians will begin to understand their precise etiology and rational medical therapy may become possible. In the future, testable hypotheses regarding the etiology of other functional bowel disorders (e.g., functional dyspepsia, irritable bowel syndrome, and so forth) may be developed.

Neuropathology and pathogenesis of diabetic autonomic neuropathy

Autonomic neuropathy is a significant complication of diabetes resulting in increased patient morbidity and mortality. A number of studies, which have shown correspondence between neuropathologic findings in experimental animals and human subjects, have demonstrated that axonal and dendritic pathology in sympathetic ganglia in the absence of significant neuron loss represents a neuropathologic hallmark of diabetic autonomic neuropathy. A recurring theme in sympathetic ganglia, as well as in the pot-ganglionic autonomic innervation of various end organs, is the involvement of distal portions of axons and nerve terminals by degenerative or dystrophic changes. In both animals and humans, there is a surprising selectivity of the diabetic process for subpopulations of autonomic ganglia, nerve terminals within sympathetic ganglia and end organs, from end organ to end organ, and between vascular and other targets within individual end organs. Although the involvement or autonomic axons in somatic nerves may reflect an ischemic pathogenesis, the selectivity of the diabetic process confounds simple global explanations of diabetic autonomic neuropathy as the result of diminished blood flow with resultant tissue hypoxia. A single unifying pathogenetic hypothesis has not yet emerged from clinical and experimental animal studies, and it is likely that diabetic autonomic neuropathy will be shown to have multiple causative mechanisms, which will interact to result in the variety of presentations of autonomic injury in diabetes. Some of these mechanisms will be shared with aging changes in the autonomic nervous system. The role of various neurotrophic substances and the polyol pathway in the pathogenesis and treatment of diabetic neuropathy likely represents a two-edged sword with both salutary and exacerbating effects. The basic neurobiologic process underlying the diabetes-induced development of neuroaxonal dystrophy, synaptic dysplasia, defective axonal regeneration, and alterations in neurotrophic substance may be mechanistically related.

Impaired gastrocolonic response and peristaltic reflex in slow-transit constipation: role of 5-HT(3) pathways

Colonic motility is modulated by the 5-hydroxytryptamine (5-HT)(3)-dependent gastrocolonic response and 5-HT(3)-independent peristaltic reflex. We compared descending colon tone responses to antral distension, duodenal lipid perfusion, and colonic distension after double-blind placebo or granisetron in 13 healthy volunteers and nine slow-transit constipated patients. Antral distension (100-300 ml) and duodenal lipids (3 kcal/min) evoked increases in colon tone in volunteers, which were blunted in constipated patients (P < 0.05). Granisetron (10 microg/kg) reduced responses to antral distension and lipids in volunteers and to lipids in constipated patients (P < 0.05). The ascending contraction of the peristaltic reflex was blunted in constipated patients (P < 0.05), whereas descending responses were similar. Granisetron did not modify the peristaltic reflex. Colonic responses to bethanechol were similar in patients and volunteers. In conclusion, antral distension- and duodenal lipid-activated gastrocolonic responses and ascending contractions of the peristaltic reflex are impaired with slow-transit constipation with loss of both 5-HT(3)-dependent and -independent function. Thus abnormalities of neural reflex modulation of colonic motor function may play pathophysiological roles in slow-transit constipation.

Rectal and colonic distension elicit viscerovisceral reflexes in humans

Colonic transit is slowed in patients with disordered rectal evacuation, but the mechanism of this phenomenon is unclear. Our objective was to investigate rectocolonic inhibitory reflexes in humans to provide potential insight into patients with obstructed defecation. In 30 healthy subjects, a barostat-manometric assembly recorded colonic tone and phasic activity in the descending colon during rectal distension and recorded rectal tone during colonic distension. Phasic distensions were 8, 16, and 32 mmHg above balloon operating pressure, and staircase inflations were comprised of balloon inflation then deflation in 2-mmHg increments at 30-s intervals from 0 to 36 mmHg. Colonic balloon volumes increased to a similar extent during phasic rectal distensions 8, 16, and 32 mmHg above operating pressure, reflecting reduced colonic tone; balloon volumes also increased and phasic pressure activity decreased during staircase rectal distensions. In contrast, rectal balloon volume declined, reflecting increased tone during phasic and staircase colonic distensions. Thus rectal distension inhibited colonic motor activity, indicative of a viscerovisceral inhibitory reflex.

Intussusception in an adult patient with severe hyperglycaemia--a case report

AIMS

To report a case of adult intussusception associated with and possibly induced by acute hyperglycaemia.

METHODS

We present the first case report of adult intussusception with severe hyperglycaemia. Clinical and laboratory data together with radiological findings are presented with a brief review of the literature.

RESULTS

A 20-year-old man with no past medical history presented with abdominal pain for 2 days. The patient was severely hyperglycaemic with blood glucose of 72.7 mmol/l (normal 3.3-6.1 mmol/l), a pH of 7.2 and serum potassium of 6.5 mmol/l (normal 3.5-5.0 mmol/l). He had a computed tomography (CT) scan of the abdomen that revealed small bowel intussusception. Upon treatment of his hyperglycaemia, the patient's abdominal pain completely resolved. Follow up abdominal CT revealed complete resolution of the previously detected intussusception.

CONCLUSION

Clinicians should be aware of the potential for the occurrence of intussusception in severely hyperglycaemic patients. Correction of hyperglycaemia could lead to resolution of the intussusception without surgical intervention. Possible effects of hyperkalaemia and/or acidosis on gastrointestinal motility should also be considered.

Decreased efficacy of polyethylene glycol lavage solution (golytely) in the preparation of diabetic patients for outpatient colonoscopy: a prospective and blinded study

OBJECTIVES

The aim of the present study was to compare, in a prospective and blinded fashion, the efficacy of 6 L of polyethylene glycol-based lavage solution (Golytely) administered on an outpatient basis in diabetic versus nondiabetic patients.

METHODS

A total of 54 consecutive nondiabetic and 45 consecutive diabetic patients requiring outpatient colonoscopy underwent colonic cleansing by drinking 6 L of Golytely the evening before the procedure. The entire procedure, from rectum to cecum, was videotaped and coded for later review by the Chief of Endoscopy who was blinded to the identity and medical history of the patients. The primary outcome measure was the quality of the preparation score, numerically rated on a 14-point scale (0-13) based on the surface area of the mucosa that could be examined and the consistency of the residual stool.

RESULTS

There was a significant difference in the quality ratings for the bowel preparations, with an overall superior preparation in the nondiabetic group (2.4+/-1.6 vs 5.4+/-3.1, p < 0.001). A total of 97% of the nondiabetic patients had a preparation rated as good or better, compared with only 62% of the diabetic patients (p < 0.001). Preparations rated as poor or futile, necessitating repeat colonoscopy, occurred in no nondiabetic but in 9% of diabetic patients (p < 0.01). Within the diabetic group, there was no significant difference in bowel preparation scores between those patients aged >70 yr and those <70 yr, those requiring and those not requiring insulin, those with Hb A1c values >8% and those with values <8%, and those with and without peripheral neuropathy.

CONCLUSION

We conclude that diabetic patients (irrespective of insulin use, diabetic control, or diabetic neuropathy) have a significantly poorer response to a 6-L Golytely preparation than do nondiabetic patients.