The Gastroenterologist最新文献

Esophageal disorders in children can result in significant morbidity. The most common esophageal disorder seen in children is gastroesophageal reflux. Other common disorders affecting the esophagus include peptic esophageal strictures, esophageal atresia with or without tracheoesophageal fistula, caustic and foreign body ingestions, achalasia, and cricopharyngeal achalasia. We discuss what is currently known about these common pediatric esophageal disorders with regard to pathophysiology, clinical presentation, and diagnostic and treatment strategies.

Hepatorenal syndrome is a progressive oliguric renal failure complicating the course of advanced cirrhosis and ascites. Significant hemodynamic changes occur in these patients consisting of marked systemic arterial vasodilatation and renal vasoconstriction. Traditionally, the systemic arterial vasodilatation with the consequent underfilling of the effective arterial blood volume has been held responsible for the pathogenesis of the renal vasoconstriction. Recent data showing a dissociation between the extent of arterial underfilling and the development of renal dysfunction in these patients have lead to the proposal of a hepatorenal interaction directly causing the renal vasoconstriction, with arterial underfilling secondarily contributing further to the renal vasoconstriction. Diagnosis of hepatorenal syndrome remains one of exclusion. Treatment is largely ineffective except for liver transplantation, which unfortunately is not available to all patients because of their short survival. Prognosis is very poor once it has developed. Therefore, physicians should be alert to avoid precipitating factors in these patients. Recent development of new therapies such as the use of a transjugular intrahepatic portosystemic shunt or systemic vasoconstrictors appear promising, but their efficacy should be evaluated in prospective randomized controlled trials.

Although the formula for weight control is a simple matter, namely ensure that calories consumed equals calories expended, its implementation is a source of great frustration for an estimated 85 million Americans. This results in an estimated 40 billion dollars spent each year in health and related treatment costs. This review outlines the epidemiology, health consequences, and treatment of obesity with an emphasis on newer developments in our understanding of the etiology of obesity and its treatment.

Neuromuscular conditioning using biofeedback techniques is a useful method of treatment for patients with refractory defecation disorders such as fecal incontinence or constipation with obstructive defecation. This article provides current perspectives regarding the principles and techniques of performing biofeedback therapy. In patients with incontinence, the goals are to improve the strength of the anal sphincter, improve sensory perception, and improve coordination between the rectum and anal sphincter. In patients with obstructive defecation, the goals are to relax the anal sphincter, improve rectoanal coordination, and improve sensory perception. Neuromuscular conditioning is an instrument-based learning technique. Over the years, several devices and methods have become available for performing this training, but no single method is either superior or universally popular. The three modalities that are commonly used for neuromuscular conditioning are visual, verbal, and audio feedback. Ideally, the training program should be customized for each patient based on the underlying dysfunction(s). After biofeedback therapy, symptomatic improvement has been reported in 70 to 80% of patients with either incontinence or obstructive defecation. Recent studies also demonstrated objective improvement in anorectal function. In the future, it is likely that simpler and user-friendly, solid-state computerized systems may facilitate a wider use of this treatment.

Physicians frequently order batteries of tests that are used to assess liver injury or function. These tests are frequently ordered to screen for disease. However, a lack of understanding of the nature of the assays and the laboratory assignment of normal versus abnormal often leads to unnecessary workup or missed disease. We attempt to describe the nature of the most commonly used laboratory tests for liver disease, including alanine and aspartate aminotransferases, alkaline phosphatase, bilirubin, and gamma glutamyl transpeptidase. In addition, the role of functional tests of the liver, including prothrombin time, and metabolite clearance tests, such as aminopyrine and monoethylglycinexylidine, are examined.

Clostridium difficile is the most common nosocomial pathogen of the gastrointestinal tract. Disease is usually a consequence of antibiotic therapy, but sporadic cases do occur. Cytotoxin assay for toxin B remains the gold standard for confirming diagnosis. Several rapid enzyme immunoassay tests are available, but specificity and sensitivity vary; a negative test may not exclude disease. Oral metronidazole 250 to 500 mg four times a day is the recommended first-line therapy; vancomycin (125 mg four times a day) should be reserved for patients who cannot tolerate metronidazole, who do not respond to this drug, or who should not take it for various reasons (i.e., pregnancy). Recurrent C. difficile disease is a difficult problem. The nonpathogenic yeast Saccharomyces boulardii has been shown in controlled trials to be effective in reducing recurrences when given as an adjunct to standard therapy. Prevention of epidemics relies on careful hand washing and environmental decontamination.

Some epidemiological data point to an association between infection from Helicobacter pylori (Hp) and gastric cancer, although several unresolved issues still cast doubts on the real weight of this association. These issues are as follows: the male-to-female ratio of gastric cancer ranges from 4:1 to 1.5:1 in all studies, whereas the prevalence of Hp infection is the same in both sexes; the prevalence of Hp infection is as high as 90% in several developing countries where the frequency of gastric cancer is very low; the acquisition of the infection at a young age, considered very important with regard to the risk for cancer, varies from 4.2% to 83% in several countries in which the mortality for stomach cancer is approximately 10 in 100,000; and the incidence of cancer in patients with a duodenal ulcer is half that of the general population, but Hp infects up to 100% of these patients. In the sequence of events that leads to gastric cancer, Hp appears to play a role only in the very initial steps, as a causative agent of chronic inflammation. The further events that cause gastric atrophy, intestinal metaplasia, dysplasia, and cancer are multifactorial, involving environmental agents and the host response. It is therefore inappropriate to consider Hp a direct carcinogen for humans. This also applies to specific strains of the bacterium such as the cagA gene. In fact, Hp infection is widespread in humans, and only a small minority will ever be affected by peptic ulcer and cancer.