Seminars in gastrointestinal disease最新文献

Bariatric surgery has undergone significant change in the past several decades. There are now several attractive surgical options for the management of clinically severe obesity (body mass index > 40 kg/m2). Gastric restrictive procedures predominate and have been performed with acceptable complication rates. Long-term weight loss is frequently > 50% excess weight with amelioration of obesity-related illnesses. Laparoscopic approaches are increasingly popular. Patient selection and appropriate follow-up remain challenging aspects of patient care. In summary, bariatric surgery is a reliable option for the surgical management of clinically severe obese patients.

Management strategies in the nutritional support of the patient with acute pancreatitis have changed dramatically over the past 10 years. Prospective randomized trials show that maintaining gut integrity is equally as important as placing the pancreas at rest while inflammation within the gland resolves. In comparison to total parenteral nutrition and gut disuse, enteral feeding attenuates disease severity, reduces oxidative stress, and improves patient outcome. Nasojejunal feeds infused at or below the Ligament of Treitz should be provided to those patients with severe pancreatitis, as identified by a number of standardized scoring systems such as Ranson Criteria, APACHE II, Glasgow, and Imrie scores. Total parenteral nutrition should be reserved only for the patient with severe pancreatitis, initiated 4 to 5 days after peak inflammation in whom intolerance to enteral feeding has been shown and/or enteral access cannot be obtained. Vigilant monitoring is required to assure safe and effective delivery of enteral nutrients.

Malnutrition is a common problem in patients with acute and chronic liver disease, and it is near universal in patients undergoing liver transplantation. The cause of malnutrition in liver disease is multifactorial. This article reviews the prevalence of malnutrition, its pathophysiology, modalities of assessing nutritional status, and general guidelines for nutritional support in this patient population.

Obesity is the most prevalent and serious nutritional disease among western countries and is rapidly replacing undernutrition as the most common form of malnutrition in the world. Approximately 300,000 deaths a year are currently associated with overweight and obesity, second only to cigarette smoking as a leading cause of preventable death in the United States. Obesity effects 9 organ systems and is a risk factor for gastroesophageal reflux disease, nonalcoholic fatty liver disease, cholelithiasis, and colon cancer. Evidence-based guidelines on the identification, evaluation, and treatment of overweight and obesity have recently been developed by the National Institutes of Health to help practitioners effectively manage their patients. The body mass index is used to classify weight status and risk of disease. Treatment for obesity includes lifestyle management, consisting of diet therapy, physical activity, and behavioral modification, and may include pharmacotherapy or surgery based on level of risk. Currently only 2 medications, sibutramine and orlistat, are approved for long-term use. An initial weight loss of 10% of body weight achieved over 6 months is a recommended target. This article reviews the evaluation and management of the adult obese patient.

Evidence emerging from many different types of experimental designs continues to support the concept that dietary habits, and nutritional status, play important roles in determining the risk of developing colorectal cancer. Overall, a diet habitually high in fresh fruits and vegetables, modest in calories and alcohol, and low in red meat and animal fat is cancer protective. This field of investigation is nevertheless very confusing, particularly because longstanding hypotheses, such as the presumed protective effects of fruits, vegetables, and fiber, have recently been challenged by well-designed prospective trials. The search for individual components in the diet that convey protection continues: calcium, folate, and selenium are the leading candidates in this regard. There is also growing interest in other plant-based compounds, so-called phytochemicals, although our understanding of their effects is quite rudimentary at present. However, regardless of the constituent components of the diet, evidence continues to accrue that ingesting a sensible amount of calories and maintaining a desirable weight also play important roles in prevention of this cancer. Although the inconsistencies in this field make it tempting to minimize its import, there is little question that diet has a major impact on colorectal cancer risk; diligent attention to the rigorous conduct of studies and their interpretation will likely clarify these relationships over the next decade, much to the benefit of public health.

Short-bowel syndrome refers to malabsorption, diarrhea, and weight loss following an extensive resection of small bowel. A main consequence is malabsorption of macro- and micronutrients. Nutritional outcome after intestinal resection depends on the extent and location of resection, presence of ileocecal valve and a colon, functional status of the residual intestine, and adaptation. Intraluminal nutrients and trophic factors are critical for intestinal adaptation. The dietary management is focused on the enhancement of intestinal adaptation and optimal caloric intake. Patients with short-bowel syndrome require an individualized diet, and some may require total parenteral nutrition indefinitely. Growth hormone, glutamine, and GLP-2 are reviewed with emphasis on their current use in clinical practice. The nutritional aspect of short-bowel syndrome is complex, with the ultimate goal of weaning the patients from parenteral nutrition. Intestinal transplant is a treatment option for select patients.

Owing to its high incidence and anatomical accessibility, colorectal cancer has become the most extensively studied human neoplasm with respect to molecular pathogenesis. Many of the genomic alterations that occur when a normal colonic epithelial cell gradually is transformed into a malignant cell have been well characterized. An understanding of the molecular basis of colorectal cancer will lead to better cancer control through novel and scientifically based cancer risk assessment, diagnostics, prognostics, and therapeutics. It is imperative that clinicians possess a basic understanding of the molecular pathogenesis of colorectal cancer so that they are poised to embrace new, molecularly based, preventive and treatment measures. This task is formidable given the rapidly expanding body of scientific knowledge on the genomics of colorectal cancer.

A large body of clinical evidence supports the belief that over 95% of colorectal cancers arise in benign adenomatous polyps that develop and grow very slowly over many years. Interruption of the adenoma-carcinoma sequence by resecting adenomatous polyps is a powerful method of secondary prevention of colorectal cancer. Colonoscopy is the procedure of choice for the diagnosis and resection of colorectal polyps. Patients who have had colonoscopic resection of adenomas, and in some cases their close relatives, are at increased risk for developing metachronous polyps and cancer and may benefit from follow-up colonoscopic surveillance. This surveillance should be individually tailored to the perceived risk of each case depending on the features of the adenomas removed and other patient factors such as family history. Widespread adoption of current postpolypectomy guideline recommendations is protective and conserves medical resources.

Cost-effective use of colonic imaging studies can be achieved through an understanding of the prevalence, incidence, growth, and miss rates of colon adenomas. High adenoma prevalence rates are associated with increasing age, male gender, and a family history of colorectal cancer or multiple first-degree relatives with colorectal neoplasia or neoplasia diagnosed at a young age. The incidence rate of advanced adenomas is higher in patients with multiple adenomas and is likely also associated with a family history of colorectal cancer, increased age, and large adenoma size at the index examination. Direct observational data on growth rates suggests that adenomas <1 cm in size have a fairly stable size over a 3-year interval. Although colonoscopy is the most sensitive colonic imaging study, substantial miss rates for small adenomas are inherent to the procedure. Advancements in endoscopic technology should lead to reduced miss rates, allowing expansion of intervals between examinations while reducing negative outcomes of fatal interval cancers.