Peptic Ulcer Disease and Helicobacter Pylori Fact Sheet

• There are 350,000 to 500,000 new cases per year.
• There are more than one million ulcer-related hospitalizations each year.
• Direct costs to the health care system are more than $2 billion per year.
• Indirect costs (time lost from work, time spent unproductively) are more than $500 million.

H. pylori

A Brief History
For years, ulcers were considered functions of acid in the stomach. While the idea of bacteria being present in the stomach has been around for more than 20 years, much of the medical community believed that bacteria could not survive in the stomach's hostile environment. Now one strand of bacteria, called Helicobacter pylori, has been shown to survive--even thrive--in such an environment and is believed to be the cause of most peptic ulcers. This is good news for ulcer sufferers, because once the bacteria is eradicated, ulcer disease is cured. 

Characteristics

• Helicobacter pylori, or H. pylori, is a stomach microbe now believed to be associated with a number of common upper GI disorders:
• Virtually always present in the inflammation of the stomach
• In the vast majority of duodenal and gastric ulcer patients
• In about 50% of individuals with heartburn
• Evidence of past infection in the vast majority of gastric cancer patients
• A spiral-shaped gram-negative bacterium with four to six flagella found in the mucous layer of the stomach or duodenum
• The spiral shape and flagella aid movement through the mucous layer
• It is a potent producer of the enzyme urease. Urease provides the organism an alkaline microenvironment, which helps it survive in the hostile acidic environment of the stomach and disrupts the mucous layer structure.
• It produces chronic infection, and once a person is infected--usually in childhood--it's probably for life.
• It is found worldwide, but more prevalent in developing countries. There is an inverse relationship between infection and socioeconomic status, possibly due to factors such as sanitary conditions, familial clustering and crowding.

Diagnosing a Medical Breakthrough

Definitive diagnosis of H. pylori infection requires either direct evidence of its presence, such as microscopic documentation or culture, or indirect evidence, such as blood or biomedical assays that detect urease, a by-product of the bacteria. Both invasive and noninvasive tests for H. pylori have been developed and are described as follows:

Noninvasive

Urea Breath Test (UBT)

• H. pylori produces urease, an enzyme that breaks down a substance called urea to form ammonia and bicarbonate.
• The patient swallows urea in water. If H. pylori is present, the urea is metabolized as ammonia and bicarbonate, which is measured by exhalation of "labeled" carbon dioxide.
• UBT, positive only if current infection exists, is the best test for confirming eradication of H. pylori. It should be used four weeks after treatment.

Blood test

• Chronic H. pylori infection elicits a local and a systemic immune response detectable in the blood.
• Best applied when endoscopy is not required or indicated
• Useful for identifying past exposure; should not be used to monitor immediate effects of antibacterial therapy, because it can take months for the immune response to disappear
• Several FDA-approved tests currently available

Invasive

Biopsy Urease Test

• Like the UBTs previously mentioned, the biopsy urease test is based on the ability of H. pylori to produce the enzyme urease, breaking down urea into ammonia and bicarbonate.
• Several samples of tissue from the stomach are taken at the time of endoscopy. A gel containing urea changes color from yellow to pink in the presence of a pH above six.
• Excellent for initial diagnosis with endoscopy
• Easy to perform
• Results within hours

Histology

• Tissue sampling is considered the gold standard of diagnostic tests, identifying H. pylori by appearance with a routine stained tissue sample.
• Excellent for initial diagnosis with endoscopy
• Widely available
• Serves as a permanent record
• Assesses the severity of gastritis and confirms the presence of H. pylori

Culture

• Culturing stomach tissue at endoscopy provides extremely accurate identification and the opportunity to perform antibiotic sensitivity testing, but culture can be difficult.
• Not widely available
• Requires laboratory expertise

Additional Information

National Digestive Diseases Information Clearinghouse
7830 Old Georgetown Road
Suite 204
Bethesda, MD 20814
301-654-3810
nddic@info.niddk.nih.gov