Acid-peptic diseases of the stomach and duodenum including Helicobacter pylori and NSAIDs

Published on May 5, 2014 Updated on August 7, 2014   48 min

Other Talks in the Series: Gastroenterology and Hepatology

0:00
My name is Sheila Crowe. I'm a professor of medicine at the University of California in San Diego. I'm going to be discussing acid peptic diseases of the stomach and duodenum, including H. pylori infection and NSAIDs.
0:19
To start, I would like to talk about the clinical presentations of H. pylori infection. The most common presentation is an asymptomatic infection in which the patient has no idea they're infected. Another presentation is indigestion, or what we call this dyspepsia. Additionally, H. pylori can lead to gastric ulcer and also duodenal ulcer. Perhaps one of the more serious long term presentations of H. pylori infection is the development of gastric adenocarcinoma, and a relatively rare presentation is a special kind of lymphoma known as the MALT lymphoma, because it involves the Mucosal Associated Lymphoid Tissue.
1:07
In modern times, we've recognized that this infection, which we think dates back many years, has actually changed in its incidence in association with different upper gastrointestinal diseases. If you look at the graph, you will see the relative incidence of the event, the different types of presentations of upper GI problems, and you'll see over the decades going from 1900 to more modern times that there has been a decline in the H. pylori infection, and with that you see a decrease in duodenal ulcer, gastric ulcer, and in Western countries, gastric cancer. At the same time, there have been some other changes, which we won't get into much detail here, is the rise of reflux esophagitis, Barrett's esophagus, and adenocarcinoma of the esophagus. Now this diagram does not apply to Eastern countries and some more of the developing countries in the world where H. pylori remains quite prevalent.
2:15
Microbiologic factors. H. pylori are a gram negative organism that is spiral-shaped and is microaerophilic. It's a bit of a unique organism because it only lives in the stomach or adheres to gastric-type epithelium. It allows itself to live in the very harsh acid environment of the stomach by expressing an enzyme urease, which can produce a more alkaline atmosphere for the bacteria to live in, rather than in very low pH surroundings.
2:50
H. pylori has a very interesting history. It originated in Africa 60,000 years ago, but it's relatively recently that it was recognized as an infection. It dates back over 100 years when it was first recognized in pathology samples from the stomach. It was first isolated from the stomach in 1982. Barry Marshall, an internal medicine resident at the time, and Robin Warren, a pathologist, won the Nobel Prize for this discovery in 2005. Dr Marshall actually proved Koch's postulates by infecting himself with H. pylori infection, and he developed gastritis.
3:34
When we consider the epidemiology of this infection, it's important to realize that this is the most common chronic bacterial infection in humans. It is usually contracted by children within the first two years of life. It is relatively rare for adults to develop this infection. Prevalence of infection varies by area. We know that increased prevalence of infection occurs in lower socioeconomic status settings and in poor living conditions in crowded situations. The prevalence of infection can be as high as 80% to 100% in some regions of the world. And in the developed countries, the prevalence has continued to decrease such that it's in the range of 20% to 30% in countries such as the United States and Western Europe. The organism resides in the stomach-- the lining, as I've said, of the stomach-- and can be found in both the two major compartments of the stomach, the antrum and the body.
4:38
Other factors regarding the epidemiology of this organism seems to relate it to the consumption of various types of foods, including salted foods. It appears in certain countries, such as the United States, that there's an increased prevalence of infection in Hispanic and African-American as compared to Caucasians in the United States. It's also found in immigrants that come from Central, South America, Eastern Europe, and Asia, which we remain relatively highly infected compared to Western Europe and the United States and Canada. There is some evidence of human genetic susceptibility to developing H. pylori infection and particularly certain outcomes, such as gastric cancer. The method of transmission from human to humans is unclear. It's believed that it may be from oral to oral in cultures where the mother masticates food and then feeds it to the baby. It appears there's a fecal-oral conduction. And other mechanisms are not fully established at this time.
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Acid-peptic diseases of the stomach and duodenum including Helicobacter pylori and NSAIDs

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