Seminars in gastrointestinal disease最新文献

The role of the brain-gut axis has traditionally been investigated in relation to intestinal motility, secretion, and vascularity. More recently, the concept of brain-gut dialogue has extended to the relationship between the nervous system and mucosal immune function. There is compelling evidence for a reciprocal or bi-directional communication between the immune system and the neuroendocrine system. This is mediated, in part, by shared ligands (chemical messengers) and receptors that are common to the immune and nervous systems. Although the concept of psychoneuroimmunology and neuroimmune cross-talk has been studied primarily in the context of the systemic immune system, it is likely to have special significance in the gut. The mucosal immune system is anatomically, functionally, and operationally distinct from the systemic immune system and is subject to independent regulatory signals. Furthermore, the intestinal mucosal immune system operates in a local milieu that depends on a dense innervation for its integrity, with juxtaposition of neuroendocrine cells and mucosal immune cells. An overview of evidence for the biologic plausibility of a brain-gut-immune axis is presented and its potential relevance to mucosal inflammatory disorders is discussed.

At present, the medical management of inflammatory bowel diseases (IBD) including Crohn's disease and ulcerative colitis, are focused on topical, locally active antiinflammatories and systemic immunosuppressives, which are thought to exert their targeted effects in the gastrointestinal mucosa. There is a paucity of controlled trials assessing the impact of mind, central nervous system (CNS), and neuromodulation on the overly active immune response in the intestinal mucosa. Patients and their physicians have long been aware of a strong association between attitude, stress, and flares of their IBD. Although reports to date remain mostly anecdotal, the degree to which mind-body influences and stress impact levels of local inflammation deserves closer attention with the aim of identifying contributing mechanisms, which may highlight new therapeutic interventions, as well as assist in identifying particular subsets of patients that may respond to novel forms of adjunctive treatments for IBD, including hypnosis, meditation, neuropeptide receptor modulation, and cortisol-releasing factor (CRF) modulation.

Psychoneuroimmunology is the scientific field that investigates linkages between the brain, behavior, and the immune system and the implications of these linkages for physical health and disease. Recent evidence suggests that both naturalistic and laboratory stressors can alter enumerative and functional aspects of the human immune system. Chronic stress may increase vulnerability to infectious disease; however, the role of stress in the course of inflammatory bowel disease remains unclear. Because there are large individual differences in psychological response to stress, it is important to consider the role of cognitive and affective responses to stress. Depression has been associated with functional immune decrements and immune overactivation. Cognitive states such as perceived control, views of the self, and views of the future have been associated with immune parameters and health in some studies. Very few controlled clinical trials have been conducted to determine if psychosocial interventions can impact the immune system and the progression of medical conditions. There is suggestive evidence for the health benefits of relaxation training, cognitive-behavioral stress management, and support groups; but, there is little research on many other psychosocial interventions in widespread use for medical conditions. An evidence-based discussion of this research literature with interested patients may help them make informed decisions regarding adjunctive treatments.

Surgery is becoming an increasingly common method for treatment of morbid obesity in the United States. This text includes the presentation of a typical morbidly obese man with a number of obesity related comorbidities who was treated with a modification of Roux-en-Y gastric bypass. Subsequently, the gastrointestinal operations currently in use as treatment for morbid obesity are discussed. Preoperative and postoperative care for this patient population is discussed briefly. The results of the various procedures are also discussed in terms of both complications and improvement of medical comorbidities.

The prevalence of eating disorders, such as anorexia nervosa, is increasing in young adults, particularly young adult women. Sometimes, gastrointestinal complaints in patients with anorexia nervosa may lead to an erroneous diagnosis of gastrointestinal disease and unnecessary diagnostic studies and therapies. In contrast, patients with gastrointestinal disease may experience anorexia because of abdominal pain and other gastrointestinal symptoms induced by eating. In these patients, anorexia minimizes symptoms and can obscure the underlying gastrointestinal disease by "resting" the bowel. Therefore, a careful history and physical examination and laboratory tests are needed to make the correct diagnosis and begin appropriate treatment.

A 36-year-old women with severe acute pancreatitis induced by familial hyperlipidemia is presented. Ranson's score, APACHE-II score, assessment of organ function, and a computed tomography scan are used to diagnose the severity of pancreatitis. Withholding oral alimentation, parenteral analgesia, fluid resuscitation, and antibiotics all serve important roles in management of this disease. Protein-calorie malnutrition can easily develop as a result of no oral intake and hypercatabolism. Tube feeding into the jejunum using a partially hydrolyzed formula has been reported in modest to severe pancreatitis. If tube feeding is not tolerated or a feeding tube cannot be properly positioned, parenteral nutrition may be necessary to maintain bowel rest. Parenteral nutrition administered to patients with pancreatitis is associated with catheter-related infection, hyperglycemia, and hypertriglyceridemia. These complications can be managed through careful design of parenteral solutions and close monitoring.

Anorexia is a common problem in HIV infection and occurs via several mechanisms, including local pathology in the oral cavity or esophagus, central nervous system disease affecting eating mechanics or the perception of hunger, or secondary anorexia due to systemic infections, malabsorption, or medications, or to nonmedical factors, such as psychosocial problems, poverty, and isolation. The etiologic diagnosis of disorders of food intake is facilitated by using a diagnostic algorithm. The consideration of nutritional management centers around the body's nutritional reserves in addition to caloric intake. The specific management of a patient with poor food intake is based on the precise cause of the problem, and may include food-based and oral supplement therapies, appetite stimulants, or nonvolitional feeding via the enteral or parenteral route. Anabolic agents, cytokine inhibitors, and other therapies, such as resistance exercise, are adjunctive therapies, and do not replace adequate caloric intake.

Obesity is a heterogeneous condition. Some individuals suffer severe, life-threatening medical complications as a result of their obesity, whereas others appear to remain healthy for their entire lives despite substantially greater-than-normal amounts of body fat. A personal or family history of adverse health consequences of obesity and an upper-body fat distribution suggests that the patient will have greater health risks from obesity, and these patients stand to benefit more from successful treatment. Therefore, one can justify more aggressive approaches in helping them to make permanent changes in eating and exercise behavior, which are the cornerstones of obesity management. Supplementing these interventions with behavior therapy is necessary for patients unable to make lifestyle changes by themselves. Pharmacotherapy is appropriate for patients with medically complicated obesity in whom other approaches have not succeeded.

Bulimia nervosa often has an obscure presentation that requires a high level of suspicion by physicians. Awareness of subtle signs and knowledge of important questions to pursue are critical to a physician's ability to diagnose this disorder. Since bulimia nervosa may have several comorbid psychiatric disorders, such as depression, substance abuse, and personality disorders, it is important to refer patients for further evaluation and treatment. The treatment of bulimia nervosa is comprehensive and individualized and may include cognitive-behavioral therapy, group therapy, family therapy, individual psychotherapy, pharmacotherapy, or hospitalization. The comorbid disorders must also be addressed with appropriate treatment such as a drug or alcohol rehabilitation program for substance abusers. Although the prognosis can be variable, the majority of bulimic patients have a serious chronic illness with remissions and exacerbations.

Despite a declining incidence, infections remain a significant complication in liver transplant recipients. The spectrum of infections in transplant recipients, however, appears to be evolving. Infections caused by gram-positive bacteria (e.g., enterococci and staphylococci) have now surpassed in frequency those caused by gram-negative bacteria. There has been a decline in the incidence of Pneumocystis carinii and more recently cytomegalovirus infection in transplant recipients, largely as a result of effective prophylaxis. Opportunistic fungal infections (e.g., aspergillosis) remain problematic. New or previously unrecognized pathogens (e.g., human herpesvirus-6) may also be a significant cause of morbidity. Evaluation of infections in transplant recipients therefore requires understanding of not only classic opportunistic infections typically encountered in these patients, but also emerging trends in epidemiology, prophylaxis, and management.