| Helicobacter pylori, or H. pylori, is a tiny bacterium that is now known to cause most cases of ulcer disease. It also may be one of the risk factors for cancer of the stomach. |
As recently as 15 years ago, all these were considered the causes of
ulcer disease. Huge markets in over-the-counter antacids and large profits
from acid-suppressant prescription medications testify to the prevalence
of ulcer disease and the willingness of patients and physicians to try any
therapy that offers relief.
| An ulcer is simply a sore in the GI tract. Most ulcers are duodenal ulcers, which occur just where the stomach empties food and acid into the beginning of the small intestine. About one-fourth of ulcers occur in the stomach themselves, and they are called gastric ulcers. Click here for pictures of real ulcers taken during endoscopy. |
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| Figure 1. Anatomy of the esophagus, stomach and duodenum. |
Most physicians and scientists were taken by surprise when Drs. Marshall
and Warren announced in 1982 that they had isolated a bacterium from the
stomach lining of persons with duodenal ulcers. The high acidity of the
stomach was long thought to protect against bacterial infection. The
existence of bacteria in the stomach had been described by German
pathologists many decades before, but this discovery was later discounted.
The bacterium was initially known as Campylobacter pylori but was
later reclassified as Helicobacter pylori. It is now considered to
be the cause of nearly all cases of duodenal ulcer and most cases of
gastric ulcer. Other causes of ulcer include medications such as aspirin,
anti-inflammatory drugs such as ibuprofen (sold as Motrin®, Advil®,
and many other names), steroids, and cancer. H. pylori has also
been shown to be a risk factor for cancer of the stomach, although the
increased risk for people who are infected is probably no more than
2-fold.
In industrialized countries such as the United States, the infection is
acquired by 1/2 to 1 per cent of the population each year. In poor
countries H. pylori infection is often found in children, but in
the US the infection is rare in children. The method of infection is
unknown. Doctors and nurses seem to have higher rates of infection than
most of the general population, and some studies have shown that doctors
and nurses who work with gastrointestinal disease have higher rates of
infection than other medical personnel.
In 1994, the National Institutes of Health sponsored a conference on H. pylori which recommended that all persons with duodenal ulcer and H. pylori infection be treated for the infection, as well as have the ulcer treated with standard acid-reduction agents. If a duodenal ulcer is treated with acid-lowering agents alone, then 75% of the time a new ulcer will occur in the same person in the following year. If H. pylori is eradicated at the time the ulcer is treated, then the recurrence rate drops to only 25%.
Diagnosis of H. pylori infection is made in one of four ways:
Each method has its advantages and disadvantages. The breath test is a useful way to check on cure after treatment, but it is not a very good test for initial diagnosis, since it cannot tell whether or not there is an ulcer, cancer, or other stomach problem. The blood test is very inexpensive, but it will often stay positive for long periods of time after cure, so it cannot be easily used to see if treatment has worked. Like the breath test, it does not diagnose an ulcer, it can only show whether the individual has ever been infected. Biopsies obtained at endoscopy may not show infection if the patient has recently taken antibiotics or certain powerful anti-ulcer drugs. In any individual person, then, the method of diagnosis is best decided by the patient and physician after taking into consideration the patient's age, symptoms, and recent medication history.
It is important to recognize that, even after eradication of the
infection and healing of the ulcer, the inflammation of the stomach
brought about by H. pylori can take months to a year to resolve.
Therefore, persistence of discomfort and pain does not necessarily mean
that treatment has failed. Treatment success rates of approximately 80-90
% have been reported with a variety of regimes that involve at least 3
drugs taken for 7 to 14 days. Treatment with fewer than 3 drugs usually
results in persistent infection. All of the regimens are fairly expensive,
although if successful they are a lot cheaper than taking ulcer medication
for life! Most of the regimens involve multiple pills - as many as 18 each
day - with often unpleasant side effects, such as metallic taste, black
discoloration of the tongue, diarrhea, and headache. To
my knowledge, all of the currently approved regimens are hazardous in
women of child-bearing age who may be pregnant or who are trying to become
pregnant.
Several drug companies have packaged together several drugs to make the
treatment more convenient, if not necessarily less expensive. Some of
these regimens include:
Other treatment regimens exist and this list is not meant to be all-inclusive.
Certainly, all persons with active duodenal ulcer should be treated, as
well as persons with a non-cancerous gastric ulcer who are not taking
aspirin or other irritant drugs. In such persons it is debatable whether a
separate test of H. pylori is necessary, since recent treatment
with antibiotics or anti-ulcer medication may result in a falsely negative
test.
People who do not have an ulcer but who do have pain and a positive H.
pylori test are a more controversial group. Most such people will not
be helped by treatment, although some will. It is important to make sure
that infection with H. pylori is not being blamed for symptoms
that may be caused by another disease.
Shoud people be treated to minimize the risk of developing cancer of the
stomach? At present, there is no evidence to support the conjecture that
treating H. pylori will reduce the risk of future gastric cancer.
The knowledge that H. pylori is a potential carcinogen may,
however, influence many people to have treatment.
It is humbling to reflect that bacterial infection of ulcers was first noticed more than a half century ago and ignored for many decades. Generations of pathologists never remarked on the small, curved bacteria until a few years ago, a prime example of the old medical adage that "the eye does not see what the mind does not know."
7/30/1998
