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.
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
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
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.
H. pylori are a gram
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.
H. pylori has a very
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
Dr Marshall actually proved Koch's
postulates by infecting himself
with H. pylori infection,
and he developed gastritis.
When we consider the
epidemiology of this infection,
it's important to realize
that this is the most common
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.
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
And other mechanisms are not
fully established at this time.