Helicobacter Pylori
This
unusual name identifies a specific bacteria that can cause infection of the
stomach. This infection can contribute to the development of diseases, such as
dyspepsia (heartburn, bloating and nausea), gastritis (inflammation of the
stomach), and ulcers in the stomach and duodenum. It will be useful to know some
things about the upper digestive tract to understand how and where Helicobacter
pylori infection can occur.
When food is swallowed, it passes through the esophagus (the tube that
connects the throat to the stomach). It then enters the larger upper part of the
stomach. A strong acid that helps to break down the food is secreted in the
stomach. The narrower, lower part of the stomach is called the antrum. The
antrum contracts frequently and vigorously, grinding up the food and squirting
it into the small intestine. The duodenum is the first part of the small
intestine, just beyond the stomach. The stomach, including the antrum, is
covered by a layer of mucous that protects it from the strong stomach acid.
It is known that alcohol, aspirin, and arthritis drugs such as ibuprofen can
disrupt the protective mucous layer. This allows the strong stomach acid to
injure underlying stomach cells. In some people, corticosteroids, smoking, and
stress appear to contribute in some way. Until the mid 1980s, it was felt that
one or more of these factors working together led to the development of
gastritis and ulcers. Since that time, evidence has been mounting that
Helicobacter pylori (H. pylori) has a major role in causing these diseases.
The
Infection
H. pylori is a fragile bacteria that has found an ideal home in the protective
mucous layer of the stomach. These bacteria have long threads protruding from
them that attach to the underlying stomach cells. The mucous layer that protects
the stomach cells from acid also protects H. pylori. These bacteria do not
actually invade the stomach cells as certain other bacteria can. The infection,
however, is very real and it does cause the body to react. Infection-fighting
white blood cells move into the area, and the body even develops H. pylori
antibodies in the blood.
H. pylori infection probably occurs when an individual swallows the bacteria
in food, fluid, or perhaps from contaminated utensils. The infection is likely
one of the most common worldwide. The rate of infection increases with age, so
it occurs more often in older people. It also occurs frequently in young people
in the developing countries of the world, since the infection tends to be more
common where sanitation is poor or living quarters are cramped. In many cases it
does not produce symptoms. In other words, the infection can occur without the
person knowing it. The infection remains localized to the gastric area, and
probably persists unless specific treatment is given.
How
is H. pylori Infection Diagnosed?
There are currently three ways to diagnose H. pylori infection. During endoscopy
(a visual exam of the stomach through a thin, lighted, flexible tube), the
physician can remove small bits of tissue through the tube. The tissue is then
tested for the bacteria. A breath test is now available. In this test, a
substance called urea is given by mouth. A strong enzyme in the bacteria breaks
down the urea into carbon dioxide, which is then exhaled and can be measured.
And finally, there is a blood test that measures the protein antibodies against
these bacteria that are present in the blood. This antibody can mean the
infection is present, or that it was present in the past and is now cleared. In
other words, a person can have a positive blood test but no infection.
Gastritis
and Dyspepsia
The symptoms are discomfort, bloating, nausea and perhaps vomiting. The person
may also have symptoms that suggest ulcers -- burning or pain in the upper
abdomen, usually occurring about an hour or so after meals or even during the
night. The symptoms are often relieved temporarily by antacids, milk, or
medications that reduce stomach acidity. Yet, the physician does not find an
ulcer when the patient is tested by x-ray or endoscopy. When H. pylori is found
in the stomach, it is tempting to believe that it is the cause of the symptoms,
although this connection is not yet clear cut. The physician will usually
prescribe antibiotic therapy to see if clearing the infection relieves symptoms.
Ulcers
Stomach Ulcers: With stomach ulcers, H. pylori infection is found in 60
to 80 percent of the cases. Again, it is still uncertain how the infection
acts to cause the ulcer. It probably weakens the protective mucous layer of
the stomach. This allows acid to seep in and injure the underlying stomach
cells. However, there is still a great deal of research to be done to unravel
this relationship.
Duodenal ulcers: In times past, physicians were taught "no
acid, no ulcer." The medical profession felt the single most important
factor causing duodenal ulcers to form was strong stomach acid. Research has
now shown that over 90% of all patients who develop duodenal ulcers have H.
pylori infection in the stomach as well. Medical studies are under way to
determine the relationship between the two and how an infection in the stomach
can be related to a duodenal ulcer. Acid is still important; patients without
acid in the stomach never get duodenal ulcers. However, physicians now accept
the fact that the infection is directly related to the development of duodenal
ulcers. It is now rather easy to clear duodenal ulcers with the strong
acid-reducing medicines available. But, the ulcers will usually recur unless
the H. pylori infection is also cleared from the stomach.
Stomach Cancer and Lymphoma
These two types of cancer are now known to be related to H. pylori bacteria.
This does not mean that all people with H. pylori infection will develop cancer;
in fact, very few do. However, it is likely that if the infection is present for
a long time, perhaps from childhood, these cancers may then develop. This is
another reason why it is important to treat H. pylori infection.
When is Treatment Necessary?
Since the infection is so common, it is sometimes recommended that no treatment
be given when there are no symptoms. However, these recommendations may change
as more research develops. Increasingly, physicians are treating the acute ulcer
with acid-reducing medicines and treating the infection with antibiotics.
Interestingly, one of these antibiotics is a bismuth compound that is available
over-the- counter as Pepto-Bismol. It is also available as a generic drug called
bismuth subsalicylate. The bismuth part of the medicine actually kills the
bacteria. However, do not go to the drugstore and purchase a bottle of
Pepto-Bismol, expecting this alone to cure the infection. H. pylori is buried
deep in the stomach mucous, so it is difficult to get rid of this infection.
Several antibiotic drugs are always used together to prevent the bacteria from
developing resistance to any one of them. Current medical studies are being done
to develop easier treatment programs for this difficult infection.
Summary
H. pylori is a very common infection of the stomach. It may be the most common
infection in the world. It is now clear that the infection is directly related
to the development of stomach and duodenal ulcers, and it is likely that it may
be related to cancers involving the stomach. There are several diagnostic tests
available, and effective treatment can prevent the recurrence of ulcers and
perhaps the development of cancer
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