What is H. pylori?
Helicobacter pylori (H. pylori) is a spiral-shaped bacterium that is
found in the gastric mucous layer or adherent to the epithelial lining of
the stomach. H. pylori causes more than 90% of duodenal ulcers and up to
80% of gastric ulcers. Before 1982, when this bacterium was discovered,
spicy food, acid, stress, and lifestyle were considered the major causes
of ulcers. The majority of patients were given long-term medications, such
as H2 blockers, and more recently, proton pump inhibitors, without a
chance for permanent cure. These medications relieve ulcer-related
symptoms, heal gastric mucosal inflammation, and may heal the ulcer, but
they do NOT treat the infection. When acid suppression is removed, the
majority of ulcers, particularly those caused by H. pylori, recur. Since
we now know that most ulcers are caused by H. pylori, appropriate
antibiotic regimens can successfully eradicate the infection in most
patients, with complete resolution of mucosal inflammation and a minimal
chance for recurrence of ulcers.
How common is H. pylori infection?
Approximately two-thirds of the world's population is infected with H.
pylori. In the United States, H. pylori is more prevalent among older
adults, African Americans, Hispanics, and lower socioeconomic groups.
What illnesses does H. pylori cause?
Most persons who are infected with H. pylori never suffer any symptoms
related to the infection; however, H. pylori causes chronic active,
chronic persistent, and atrophic gastritis in adults and children.
Infection with H. pylori also causes duodenal and gastric ulcers. Infected
persons have a 2- to 6-fold increased risk of developing gastric cancer
and mucosal-associated-lymphoid-type (MALT) lymphoma compared with their
uninfected counterparts. The role of H. pylori in non-ulcer dyspepsia
remains unclear.
What are the symptoms of ulcers?
Approximately 25 million Americans suffer from peptic ulcer disease at
some point in their lifetime. Each year there are 500,000 to 850,000 new
cases of peptic ulcer disease and more than one million ulcer-related
hospitalizations. The most common ulcer symptom is gnawing or burning pain
in the epigastrium. This pain typically occurs when the stomach is empty,
between meals and in the early morning hours, but it can also occur at
other times. It may last from minutes to hours and may be relieved by
eating or by taking antacids. Less common ulcer symptoms include nausea,
vomiting, and loss of appetite. Bleeding can also occur; prolonged
bleeding may cause anemia leading to weakness and fatigue. If bleeding is
heavy, hematemesis, hematochezia, or melena may occur.
Who should be tested and treated for H. pylori ?
Persons with active gastric or duodenal ulcers or documented history of
ulcers should be tested for H. pylori, and if found to be infected, they
should be treated. To date, there has been no conclusive evidence that
treatment of H. pylori infection in patients with non-ulcer dyspepsia is
warranted. Testing for and treatment of H. pylori infection are
recommended following resection of early gastric cancer and for low-grade
gastric MALT lymphoma. Retesting after treatment may be prudent for
patients with bleeding or otherwise complicated peptic ulcer disease.
Treatment recommendations for children have not been formulated. Pediatric
patients who require extensive diagnostic work-ups for abdominal symptoms
should be evaluated by a specialist.
How is H. pylori infection diagnosed?
Several methods may be used to diagnose H. pylori infection.
Serological tests that measure specific H. pylori IgG antibodies can
determine if a person has been infected. The sensitivity and specificity
of these assays range from 80% to 95% depending upon the assay used.
Another diagnostic method is the breath test. In this test, the patient is
given either 13C- or 14C-labeled urea to drink. H. pylori metabolizes the
urea rapidly, and the labeled carbon is absorbed. This labeled carbon can
then be measured as CO2 in the patient's expired breath to determine
whether H. pylori is present. The sensitivity and specificity of the
breath test ranges from 94% to 98%. Upper esophagogastroduodenal endoscopy
is considered the reference method of diagnosis. During endoscopy, biopsy
specimens of the stomach and duodenum are obtained and the diagnosis of H.
pylori can be made by several methods: The biopsy urease test - a
colorimetric test based on the ability of H. pylori to produce urease; it
provides rapid testing at the time of biopsy. Histologic identification of
organisms - considered the gold standard of diagnostic tests. Culture of
biopsy specimens for H. pylori, which requires an experienced laboratory
and is necessary when antimicrobial susceptibility testing is desired.
What are the treatment regimens used for H.
pylori eradication?
Therapy for H. pylori infection consists of 10 days to 2 weeks of one
or two effective antibiotics, such as amoxicillin, tetracycline (not to be
used for children <12 yrs.), metronidazole, or clarithromycin, plus either
ranitidine bismuth citrate, bismuth subsalicylate, or a proton pump
inhibitor. Acid suppression by the H2 blocker or proton pump inhibitor in
conjunction with the antibiotics helps alleviate ulcer-related symptoms
(i.e., abdominal pain, nausea), helps heal gastric mucosal inflammation,
and may enhance efficacy of the antibiotics against H. pylori at the
gastric mucosal surface. Currently, eight H. pylori treatment regimens are
approved by the Food and Drug Administration (FDA) (Table 1); however,
several other combinations have been used successfully. Antibiotic
resistance and patient noncompliance are the two major reasons for
treatment failure. Eradication rates of the eight FDA-approved regimens
range from 61% to 94% depending on the regimen used. Overall, triple
therapy regimens have shown better eradication rates than dual therapy.
Longer length of treatment (14 days versus 10 days) results in better
eradication rates.
FDA-approved treatment options
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Omeprazole 40 mg QD + clarithromycin 500 mg TID x 2
wks, then omeprazole 20 mg QD x 2 wks -OR- Ranitidine bismuth citrate (RBC) 400 mg BID + clarithromycin 500 mg
TID x 2 wks, then RBC 400 mg BID x 2 wks -OR- Bismuth subsalicylate (Pepto Bismol®) 525 mg QID + metronidazole 250
mg QID + tetracycline 500 mg QID* x 2 wks + H2 receptor antagonist
therapy as directed x 4 wks -OR- Lansoprazole 30 mg BID + amoxicillin 1 g BID + clarithromycin 500 mg
TID x 10 days -OR- Lansoprazole 30 mg TID + amoxicillin 1 g TID x 2 wks** -OR- Rantidine bismuth citrate 400 mg BID + clarithromycin 500 mg BID x 2
wks, then RBC 400 mg BID x 2 wks -OR- Omeprazole 20 mg BID + clarithromycin 500 mg BID + amoxicillin 1 g BID
x 10 days -OR- Lansoprazole 30 mg BID + clarithromycin 500 mg BID + amoxicillin 1 g
BID x 10 days |
*Although not FDA approved, amoxicillin has been
substituted for tetracycline for patients for whom tetracycline is not
recommended.
**This dual therapy regimen has restrictive labeling. It is indicated
for patients who are either allergic or intolerant to clarithromycin
or for infections with known or suspected resistance to clarithromycin.
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Are there any long-term consequences of H.
pylori infection?
Recent studies have shown an association between long-term infection
with H. pylori and the development of gastric cancer. Gastric cancer is
the second most common cancer worldwide; it is most common in countries
such as Colombia and China, where H. pylori infects over half the
population in early childhood. In the United States, where H. pylori is
less common in young people, gastric cancer rates have decreased since the
1930s.
How do people get infected with H. pylori?
It is not known how H. pylori is transmitted or why some patients
become symptomatic while others do not. The bacteria are most likely
spread from person to person through fecal-oral or oral-oral routes.
Possible environmental reservoirs include contaminated water sources.
Iatrogenic spread through contaminated endoscopes has been documented but
can be prevented by proper cleaning of equipment.
What can people do to prevent H. pylori
infection?
Since the source of H. pylori is not yet known, recommendations for
avoiding infection have not been made. In general, it is always wise for
persons to wash hands thoroughly, to eat food that has been properly
prepared, and to drink water from a safe, clean source.
What is the Centers for Disease Control and Prevention (CDC) doing to
prevent H. pylori infection?
CDC, with partners in other government agencies, academic institutions,
and industry, is conducting a national education campaign to inform health
care providers and consumers of the link between H. pylori and stomach and
duodenal ulcers. CDC is also working with partners to study routes of
transmission and possible prevention measures, and to establish an
antimicrobial resistance surveillance system to monitor the changes in
resistance among H. pylori strains in the United States.
How can I get more information about H.
pylori?
- NIH Consensus Development Conference. Helicobacter pylori in peptic
ulcer disease. JAMA 272:65-69, 1994.
- Soll, AH. Medical treatment of peptic ulcer disease. Practice
guidelines. [Review]. JAMA 275:622-629, 1996. [published erratum appears
in JAMA 1996 May 1;275:1314].
- Hunt, RH. Helicobacter pylori: from theory to practice. Proceedings
of a symposium. Am J Med 1996; 100 (5A) supplement.
- The American Gastroenterological Association, American Digestive
Health Foundation, 7910 Woodmont Avenue, 7th floor, Bethesda, MD 20814,
(301) 654-2055 telephone, (301) 654-5920 fax.
- The National Digestive Diseases Information Clearinghouse, National
Institute of Diabetes and Digestive and Kidney Diseases, National
Institutes of Health, 2 Information Way, Bethesda, MD 20892-3570, (301)
654-3810 telephone.
- Hunt RH, Thompson ABR. Canadian Helicobacter pylori Consensus
Conference. Can J. Gastroenterol 1998, 12(1):31-41.
- European Helicobacter pylori Study Group. Current European concepts
in the management of H. pylori information. The Maastricht Consensus.
Gut 1997; 41, 8-13.
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