Adil E. Bharucha

ACG practice guidelines: Esophageal reflux testing

Investigations and technical advances have enhanced our understanding and management of gastroesophageal reflux disease. The recognition of the prevalence and importance of patients with endoscopy-negative reflux disease as well as those refractory to proton pump inhibitor therapy have led to an increasing need for objective tests of esophageal reflux. Guidelines for esophageal reflux testing are developed under the auspices of the American College of Gastroenterology and its Practice Parameters Committee and approved by the Board of Trustees. Issues regarding the utilization of conventional, catheter-based pH monitoring are discussed. Improvements in the interpretation of esophageal pH recordings through the use of symptom-reflux association analyses as well as limitations gleaned from recent studies are reviewed. The clinical utility of pH recordings in the proximal esophagus and stomach is examined. Newly introduced techniques of duodenogastroesophageal reflux, wireless pH capsule monitoring and esophageal impedance testing are assessed and put into the context of traditional methodology. Finally, recommendations on the clinical applications of esophageal reflux testing are presented.

American Gastroenterological Association Technical Review on Constipation

Constipation is a very common symptom. Prompted by several advances since the last technical review 15 years ago,1 this update will identify a rational, efficacious, and ideally cost-effective approach to patients with constipation. Toward those objectives, the epidemiology, clinical assessment, diagnostic testing, and management of constipation will be discussed, primarily from the perspective of a practicing gastroenterologist. Constipation in children and secondary constipation (eg, due to spinal cord injury) in adults will not be specifically addressed. This review was prepared by updating the previous technical review with material sourced from recent reviews on chronic constipation,2–4 supplemented by selected and focused literature searches of peer-reviewed, published studies. Although recommendations are graded based on US Preventive Services Task Force (USPSTF) ratings, formal cost-effectiveness analyses have not been performed. Comparisons of diagnostic approaches, with precise estimates of specificity and sensitivities, also have not been published. Indeed, in some instances, individual diagnostic techniques have not even been standardized.

Adrenergic modulation of human colonic motor and sensory function

The effects of pharmacological modulation of adrenergic receptors on colonic motor and sensory function are unclear. We studied 40 healthy volunteers in a single-blind design; 12 received saline, and the remaining 28 received either clonidine, yohimbine, phenylephrine, or ritodrine. A barostat-manometric assembly in the left colon recorded drug effects on fasting and postprandial motor function, compliance, and sensation in response to standardized phasic balloon distensions delivered in random order. Clonidine reduced and yohimbine increased fasting, but not postprandial tone, by 63.2 ± 22.3% and 24.8 ± 8.8% (SE), respectively. Clonidine tended to reduce fasting phasic activity in the descending and sigmoid colon. A power exponential model provided the best fit to the compliance curve. Clonidine significantly increased colonic compliance. Clonidine reduced and yohimbine increased colonic perception of pain but not gas sensation during distension. Phenylephrine and ritodrine did not influence colonic motor or sensory function in the present studies. Thus α2-receptors modulate fasting colonic tone and compliance and alter perception of pain but not gas during mechanical stimulation of the colon.

Relationship between symptoms and disordered continence mechanisms in women with idiopathic faecal incontinence

Background and aims: Anal sphincter weakness and rectal sensory disturbances contribute to faecal incontinence (FI). Our aims were to investigate the relationship between symptoms, risk factors, and disordered anorectal and pelvic floor functions in FI. Methods: In 52 women with “idiopathic” FI and 21 age matched asymptomatic women, we assessed symptoms by standardised questionnaire, anal pressures by manometry, anal sphincter appearance by endoanal ultrasound and magnetic resonance imaging (MRI), pelvic floor motion by dynamic MRI, and rectal compliance and sensation by a barostat. Results: The prevalence of anal sphincter injury (by imaging), reduced anal resting pressure (35% of FI), and reduced squeeze pressures (73% of FI) was higher in FI compared with controls. Puborectalis atrophy (by MRI) was associated (p<0.05) with FI and with impaired anorectal motion during pelvic floor contraction. Volume and pressure thresholds for the desire to defecate were lower, indicating rectal hypersensitivity, in FI. The rectal volume at maximum tolerated pressure (that is, rectal capacity) was reduced in 25% of FI; this volume was associated with the symptom of urge FI (p<0.01) and rectal hypersensitivity (p = 0.02). A combination of predictors (age, body mass index, symptoms, obstetric history, and anal sphincter appearance) explained a substantial proportion of the interindividual variation in anal squeeze pressure (45%) and rectal capacity (35%). Conclusions: Idiopathic FI in women is a multifactorial disorder resulting from one or more of the following: a disordered pelvic barrier (anal sphincters and puborectalis), or rectal capacity or sensation.

American Gastroenterological Association Medical Position Statement on Constipation

This document presents the official recommendations of the American Gastroenterological Association (AGA) on onstipation. It was drafted by the AGA Institute Medical Poition Panel, reviewed by the Clinical Practice and Quality Mangement Committee, and approved by the AGA Institute Govrning Board. This medical position statement is published in onjunction with a technical review1 on the same subject, and nterested readers are encouraged to refer to this publication for n-depth considerations of topics covered by these questions. he technical review was begun before the AGA’s decision to dopt the GRADE system. However, a GRADE methodologist orked with the authors and panel to rank the quality of the vidence and strength of recommendations. The medical position statement presents information by ddressing clinically related questions and summarizing key oints from the technical review. When specific recommendaions about medical interventions or management strategies for atients with constipation are stated, the “strength of recomendation” and the “quality of evidence” are provided. The trength of recommendation is either judged as “weak” or strong” and quality of evidence is ranked as high, moderate, ow, or very low in accordance with GRADE criteria. Recomendations are highlighted by appearing within a text box. A trong recommendation implies that, based on available evience, the benefits outweigh risks and there is less variability in atient’s values and preferences. A weak recommendation imlies that benefits, risks, and the burden of intervention are ore closely balanced, or appreciable uncertainty exists in reards to patient’s values and preferences. Applying this aproach, high-quality evidence does not always result in strong ecommendations and, conversely, strong recommendations ay emerge from lower-quality evidence. Symptoms of constipation are extremely common; the prevlence is approximately 16% in adults overall and 33% in adults lder than 60 years. Many people seek medical care for constiation, but fortunately most do not have a life-threatening or isabling disorder and the primary need is for control of sympoms, although rare, life-threatening, or treatable conditions ust be excluded. If therapeutic trials of laxatives fail, specialzed testing should be considered. We suggest the following ractice guidelines for the symptom of constipation; our ratioale for these guidelines is supported by the accompanying echnical review. Constipation is a symptom that can rarely be associated with ife-threatening diseases. Current recommendations will relate o (1) rational and, where possible, more judicious diagnostic pproaches and (2) more rational and efficacious therapies that ill improve symptoms, both of which should have beneficial scal and logistic impacts on the health care system. Although he overall classification of chronic constipation into 3 categoies (ie, normal transit, isolated slow transit, and defecatory isorders) and several recommendations in this version are imilar to the prior version, there are 3 substantive changes. irst, these guidelines recommend assessment of colonic transit t a later stage, that is, only for patients who do not have a efecatory disorder or patients with a defecatory disorder that as not responded to pelvic floor retraining. Second, the evience supporting these recommendations has been evaluated sing the GRADE system, in which the strength of recommenation is rated as strong or weak and the quality of evidence is ated as high, moderate, low, or very low. Third, therapeutic ecommendations have been updated to include newer agents nd delete certain older agents.

Magnetic resonance imaging of anatomic and dynamic defects of the pelvic floor in defecatory disorders.

OBJECTIVE:Endoanal ultrasound identifies anal sphincter anatomy, and evacuation proctography visualizes pelvic floor motion during simulated defecation. These complementary techniques can evaluate obstructed defecation and fecal incontinence. Our aim was to develop a single, nonionizing, minimally invasive modality to image global pelvic floor anatomy and motion.METHODS:We studied six patients with fecal incontinence and seven patients with obstructed defecation. The anal sphincters were imaged with an endoanal magnetic resonance imaging (MRI) coil and endoanal ultrasound (five patients). MR fluoroscopy acquired images every 1.4–2 s, using a modified real-time, T2-weighted, single-shot, fast-spin echo sequence, recording motion as patients squeezed pelvic floor muscles and expelled ultrasound gel; no contrast was added to other pelvic organs. Six patients also had scintigraphic defecography.RESULTS:Endoanal ultrasound and MRI were comparable for imaging defects of the internal and external sphincters. Only MRI revealed puborectalis and/or external sphincter atrophy; four of these patients had fecal incontinence. MR fluoroscopy recorded pelvic floor contraction during squeeze and recorded relaxation during simulated defecation. Corresponding comparisons for angle change and perineal descent during defecation were not significant; only MRI, but not scintigraphy, identified excessive perineal descent in two patients.CONCLUSIONS:Pelvic MRI is a promising single, comprehensive, nonradioactive modality to measure structural and functional pelvic floor disturbances in defecatory disorders. This method may provide insights into mechanisms of normal and disordered pelvic floor function in health and disease.

American Neurogastroenterology and Motility Society consensus statement on intraluminal measurement of gastrointestinal and colonic motility in clinical practice

Abstract  Tests of gastric, small intestinal and colonic motor function provide relevant physiological information and are useful for diagnosing and guiding the management of dysmotilities. Intraluminal pressure measurements may include concurrent measurements of transit or intraluminal pH. A consensus statement was developed and based on reports in the literature, experience of the authors, and discussions conducted under the auspices of the American Neurogastroenterology and Motility Society in 2008. The article reviews the indications, methods, performance characteristics, and clinical utility of intraluminal measurements of pressure activity and tone in the stomach, small bowel and colon in humans. Gastric and small bowel motor function can be measured by intraluminal manometry, which may identify patterns suggestive of myopathy, neuropathy, or obstruction. Manometry may be most helpful when it is normal. Combined wireless pressure and pH capsules provide information on the amplitude of contractions as they traverse the stomach and small intestine. In the colon, manometry assesses colonic phasic pressure activity while a barostat assesses tone, compliance, and phasic pressure activity. The utility of colonic pressure measurements by a single sensor in wireless pressure/pH capsules is not established. In children with intractable constipation, colonic phasic pressure measurements can identify patterns suggestive of neuropathy and predict success of antegrade enemas via cecostomy. In adults, these assessments may be used to document severe motor dysfunction (colonic inertia) prior to colectomy. Thus, intraluminal pressure measurements may contribute to the management of patients with disorders of gastrointestinal and colonic motility.

Pelvic floor: anatomy and function

Abstract  The pelvic floor is a dome‐shaped striated muscular sheet that encloses the bladder, uterus, and rectum, and, together with the anal sphincters, has an important role in regulating storage and evacuation of urine and stool. This article reviews the anatomy, nerve supply, pharmacology, and functions of the anal sphincters and the pelvic floor. The internal and external anal sphincters are primarily responsible for maintaining faecal continence at rest and when continence is threatened, respectively. Defecation is a somato‐visceral reflex regulated by dual nerve supply (i.e. somatic and autonomic) to the anorectum. The net effects of sympathetic and cholinergic stimulation are to increase and reduce anal resting pressure, respectively. Faecal incontinence and functional defecatory disorders may result from structural changes and/or functional disturbances in the mechanisms of faecal continence and defecation.

Epidemiology, mechanisms, and management of diabetic gastroparesis.

Recent evidence of the significant impact of gastroparesis on morbidity and mortality mandates optimized management of this condition. Gastroparesis affects nutritional state, and in diabetics it has deleterious effects on glycemic control and secondary effects on organs that increase mortality. First-line treatments include restoration of nutrition and medications (prokinetic and antiemetic). We review the epidemiology, pathophysiology, impact, natural history, time trends, and treatment of gastroparesis, focusing on diabetic gastroparesis. We discuss pros and cons of current treatment options, including metoclopramide. Second-line therapeutic approaches include surgery, venting gastrostomy or jejunostomy, and gastric electrical stimulation; most of these were developed based on results from open-label trials. New therapeutic strategies for gastroparesis include drugs that target the underlying defects, prokinetic agents such as 5-hydroxytryptamine agonists that do not appear to have cardiac or vascular effects, ghrelin agonists, approaches to pace the stomach, and stem cell therapies.

Insights into the Pathophysiology and Mechanisms of Constipation, Irritable Bowel Syndrome, and Diverticulosis in Older People

OBJECTIVES: To review the epidemiology, pathophysiology and mechanisms of irritable bowel syndrome (IBS), constipation, and diverticulosis, for the purpose of addressing these three common conditions in older adults (>65 years of age).