Reviews & Analysis

The authors of this Review consider how a reduced prevalence of organisms that have been part of human microecology for millennia (including saprophytic mycobacteria, bifidobacteria, lactobacilli, and helminths) and cause little, if any, harm to the host, might explain the increased prevalence of immune-mediated disorders in westernized countries.

The management and treatment of gastrointestinal ailments in pregnant women require special attention and expertise because of the safety of the mother, fetus and neonate remains the primary focus. The authors of this Review discuss pharmacologic therapies for gastrointestinal conditions encountered during pregnancy, including nausea and vomiting in pregnancy, hyperemesis gravidarum, gastroesophageal reflux disease, peptic ulcer disease, irritable bowel syndrome and inflammatory bowel disease.

A wide range of expert opinions exist on the ideal case definition for hemochromatosis, and much of the debate centers on its phenotypic or genotypic diagnosis. The author of this Viewpoint discusses the controversy involved in establishing a diagnosis for the disease and provides recommendations for an appropriate case definition.

The number of patients using alternative and complementary therapies is increasing worldwide, and a large percentage have inflammatory bowel disease. This Viewpoint considers evidence for the safety and efficacy of these therapies for the treatment of inflammatory bowel disease, and the reasons why patients choose to seek alternatives to conventional medicine.

Advances in the understanding of the pathogenesis of inflammatory bowel disease have allowed rational therapeutic targets to be developed, including antagonists of tumor-necrosis factor-α. The authors of this Review provide insights into the similarities and differences of the mechanism of action, clinical efficacy and limitations of the tumor-necrosis factor-α antagonists infliximab, adalimumab, certolizumab, CDP571, etanercept, and onercept.

Malnutrition is an increasingly recognized complication of chronic liver disease. In patients with cirrhosis, malnutrition increases morbidity and mortality, and patients who are severely malnourished before transplantation have a higher rate of complications and higher post-operative mortality. The authors of this Review consider the etiologies of malnutrition, methods used to assess nutritional status, and appropriate treatment strategies.

Esophageal impedance monitoring is a new technique that can be used alone and in combination with pH-metry and manometry to evaluate bolus transport and all types of gastroesophageal reflux. The authors of this Review describe the technique and summarize the published validation studies that compare impedance monitoring with other methods. Normal values and the reproducibility of impedance patterns and their association with symptoms are also discussed.

The pathogenesis of hepatic encephalopathy and cerebral edema in patients with acute liver failure has yet to be fully elucidated. This Viewpoint considers whether infection and inflammation have a role to play, and discusses emerging data on the molecular pathways that could link ammonia to infection and inflammation in this setting.

Video capsule endoscopy (VCE) is the most recent major practical and conceptual advance in the field of endoscopy, and its widespread deployment in gastrointestinal practice suggests that it is has achieved mainstream use. In this Review, the author considers the indications for VCE, practical issues (such as patient selection and bowel preparation), and the limitations and complications of VCE, and discusses what VCE's future might hold.

The correlation between the endoscopic impression of gastritis and histologic gastritis is poor and there are few well-known histologic gastritides that yield specific diagnoses. Gastroenterologists might therefore be frustrated by the surgical pathology report accompanying a set of gastric biopsies. The authors of this Review explain common pathologic diagnoses of gastric inflammation and address communication deficiencies between pathologists and gastroenterologists.

Metoclopramide is one of the most widely used drugs for gastroenterological motility disorders, but it has many potentially troublesome neurological adverse effects, particularly movement disorders. The authors of this Review discuss the indications for metoclopramide, its side effects and common pitfalls of prescribing metoclopramide, and describe strategies to minimize the medicolegal risks to the prescribing physician.

In this Review, the authors discuss the justification for living donor liver transplantation (LDLT), the introduction of LDLT for the treatment of pediatric patients and its expansion to include the treatment of adult recipients. How pediatric and adult recipients are selected, LDLT performed, and the implications for living donors affected by these decisions are also considered.

Dietary supplements are increasingly used by a large percentage of the population worldwide. The potential impact of these supplements on our health, however, is not fully understood and their regulation is not controlled as tightly as that of drugs. This viewpoint article discusses the safety concerns and regulatory issues that surround the use of dietary supplements in the US.

Although the incidence of peptic ulcer disease and ulcer complications has decreased over the past few decades, there has been an increase in ulcer bleeding, especially in elderly patients. The authors of this Review consider the current status of understanding, diagnosis and treatment of peptic ulcer disease, and management issues that remain to be solved.

Constipation is often mild and intermittent, but can be debilitating and require medical consultation. When management with first-line conservative therapy is unsuccessful, additional studies are needed to better understand the underlying pathophysiology. This Review considers the modern principles and therapies used to manage chronic constipation of varying severities.

One area of gastroenterology that lags behind other specialties in the quality of the evidence base for clinical practice is the prevention of gastrointestinal cancer. In this Review the authors assess the evidence for various cancer prevention strategies, especially chemoprevention, and highlight the obstacles to further exploitation of this knowledge base.

This Viewpoint discusses the role of combined multichannel intraluminal impedance-pH testing in the evaluation of patients with GERD symptoms that are refractory to proton-pump-inhibitor therapy. The relationship between symptoms and reflux is important as symptoms might not be due to continuing reflux, and these patients therefore might not benefit from surgery.