Gastroenterology & Endocrinology
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Recent changes in findings at oesophagogastroduodenoscopy (OGD): clinical implications and management Written by Professor Humphrey J. O’Connor MD FRCPI AGAF Trinity Academic Gastroenterology Group - Trinity Centre for Health Sciences, Tallaght University Hospital, Tallaght, Dublin 24. email: oconnor_hj@hotmail.com
Introduction Fibreoptic endoscopy revolutionised the practice of gastroenterology allowing direct visualisation of the gastrointestinal tract and mucosal biopsy to guide accurate diagnosis and treatment of gastrointestinal (GI) disorders. With so much emphasis over the years on service demands, less attention was paid to how much findings at OGD changed to where the clinical picture at OGD today is in many ways quite different to that of 40-50 years ago. Changed findings at OGD often equate with a change in diagnosis and treatment. The aim of this paper is to describe the clinical implications of recent changes in OGD findings and their management. Peptic Ulcer Disease (PUD) The groundbreaking discovery of H. pylori infection 40 years ago pinpointed a critical factor in the causation of peptic ulcer disease (PUD) and gastric neoplasia. Assessment of H. pylori infection status using gastric biopsies is now an integral part of the conduct of OGD and despite initial scepticism, eradication of H. pylori infection has become the treatment of choice for PUD. What was not appreciated at the time of its discovery was how much the prevalence of H. pylori infection was in decline and had been for several decades largely as a result of improvements in socioeconomic conditions in childhood, coupled with improved hygiene and sanitation. There is close correlation between
the prevalence of H. pylori infection and the incidence of its related diseases and a fall in disease expression accompanied the falling infection rate. Consequently, the most obvious change in OGD findings over the past four decades is the dramatic decline in H. pylori -positive PUD and its replacement by gastro-oesophageal reflux disease (GORD). International studies show the fall in PUD is a worldwide phenomenon where the prevalence of PUD probably peaked in the early 1980’s and declined thereafter. The fall in PUD is more pronounced for duodenal ulcer compared with gastric ulcer, and most marked in younger age groups. Idiopathic peptic ulcer disease (IPUD) is diagnosed when ulcers occur where H. pylori, NSAID use, and more unusual causes of PUD have been excluded, including non- H. pylori Helicobacter infection. As H. pylori-positive PUD decreased, IPUD increased. Risk factors for IPUD may be increasing age and multiple comorbidities. In clinical practice, idiopathic ulcers tend to be multiple and recurrent, seem more susceptible to complications, and may be more refractory to treatment. In the absence of data from randomised controlled trials of treatment of IPUD, current advice is to continue full doses of proton pump inhibitors (PPIs) long-term as maintenance treatment. Despite the striking decrease in uncomplicated H. pylori-
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positive PUD, hospitalisation for complicated PUD has not decreased. The problem of peptic ulcer bleeding continues, particularly in elderly females, where about 25% of ulcers present de novo with a complication without antecedent dyspepsia. Systematic review has shown H. pylori infection and NSAIDs are independent and synergistic risk factors for both uncomplicated and bleeding PUD. Clinical trials in high risk patients have shown H. pylori eradication alone may not be enough to eliminate the risk of bleeding and suggest co-prescription of PPIs should continue long-term. Current management of idiopathic bleeding ulcers is poorly defined leaving long-term high-dose PPI therapy as perhaps the best option. Gastroesophageal Reflux Disease (GORD) Several studies have documented the increase in the prevalence of GORD at OGD. For instance, a study from Rotherham, UK found a dramatic five-fold increase in the prevalence of GORD at OGD from 1977-2001 where it was described as a new phenomenon. Epidemiological studies, and studies in primary care, have also documented the opposing time trends of PUD and GORD, the significant increase in time in the prevalence of GORD symptoms, increased GORD-related hospitalisation over the past four decades, and the rise in GORD as a worldwide phenomenon. Upper Gastrointestinal Cancer The arrival of fibreoptic endoscopy came at a time of significant and opposing changes in the incidence of gastric and oesophageal cancer, similar to what was happening between PUD and GORD. Before 1940, gastric cancer was the leading cause of cancer death in American males but went into sharp decline over the time period of 1930 – 1978. As gastric cancer declined, oesophageal adenocarcinoma (OAC) showed a dramatic increase. Diverging time trends also appeared for gastric cardia cancer. H. pylori -related cardia cancer decreased
whereas reflux-related cardia cancer increased and the curves for reflux-related cardia cancer and OAC closely mirrored each other. An important cross-sectional and longitudinal study using cancer registry data from 51 countries confirmed the presence of a worldwide negative association between the incidence and time trends of gastric cancer and OAC, and suggested H. pylori infection might be the key environmental factor exerting opposite effects on the incidence of the two cancers. Studies in H. pylori-positive and H. pylori-negative volunteers found less gastric acidity and decreased density of parietal and chief cells in the H. pylori-positive group which might in turn result in less noxious gastroesophageal refluxate theoretically protecting against OAC. Barrett’s Oesophagus (BO) Barrett’s oesophagus (BO) is defined as a condition in which metaplastic columnar epithelium that predisposes to cancer development replaces stratified squamous epithelium that normally lines the distal oesophagus. BO is an acquired condition occurring in response to gastroesophageal reflux and as the incidence of GORD has increased, so has the incidence of BO. The rise in BO has also paralleled the obesity epidemic, and abdominal obesity in particular is a strong risk factor for BO. There is also a strong inverse relationship between H. pylori infection and BO, especially Cag A-positive strains, and the apparent protective effect of H. pylori is probably mediated by decreasing GORD in infected patients. The ability to easily visualise and biopsy the lower oesophagus at OGD raised the possibility that aggressive screening, surveillance and management of BO might make an impact on the rising threat of OAC and detect OAC at an early curable stage. Surveillance for BO is now firmly established as an integral part of the OGD workload. Patients with OAC discovered as a result of BO surveillance present with earlier stage disease, are less likely to have lymph node involvement, and have better
