Helicobacter pylori (H. pylori) is a bacteriumbacteriumAny of a variety of single-celled micro-organisms that can cause infectious diseases in humans and animals. that grows in the inner lining of the stomach (mucosa). H. pylori causes a common stomach infection. It is also an important cause of stomach cancer and some types of lymphoma of the stomach.
H. pylori infection is common. Generally, rates of H. pylori infection are higher in developing countries than in developed countries. Some Canadians have much higher infection rates, including First Nations communities and immigrants from countries such as Japan, Korea and China, where there is a high incidence of H. pylori infection.
Most people are infected with H. pylori during childhood. H. pylori infection usually lasts for life unless it is treated. Most people infected with H. pylori don’t have any symptoms or health problems related to the bacterium. Some people with chronic infection develop symptoms, such as stomach pain, nausea or vomiting. H. pylori can cause chronic inflammation of the inner lining of the stomach (gastritis) and stomach ulcers. About 10%–15% of people with H. pylori infection develop peptic ulcer disease (sores or ulcers in the lining of the stomach or duodenum of the small intestine).
It is not known for sure how H. pylori spreads, but it is thought to spread through contaminated food and water. People may pick up the bacterium from food that has not been washed well or cooked properly. They may also get it from drinking water from an unclean source. It may also be passed from person to person through direct contact with the saliva or stool of an infected person.
Risk factors associated with H. pylori infection include:
H. pylori infection causes certain cancers and other illnesses.
H. pylori infection is a major cause of stomach (gastric) cancer. H. pylori causes chronic gastritis, which is thought to be the first step in the development of stomach cancer. H. pylori infection is a necessary, but not the only, cause of adenocarcinoma, which is the most common type of cancer that occurs in the non-cardia regions of the stomach. The cardia region of the stomach is the small, upper part of the stomach near the esophagus. The non-cardia regions are the remaining parts of the stomach. Adenocarcinoma accounts for up to 95% of all stomach cancers.
Less than 3% of people with H. pylori infection develop stomach cancer.
H. pylori infection is associated with a higher risk of MALT lymphoma of the stomach. This is a type of non-Hodgkin lymphoma (NHL). MALT lymphoma of the stomach accounts for less than 2% of all stomach cancers. Nearly all MALT lymphomas of the stomach are related to H. pylori infection. People infected with H. pylori have a low risk of developing MALT lymphoma (less than 1%).
H. pylori has been linked with other cancers, such as pancreatic and colorectal cancer, but there is not enough evidence to say for sure whether or not it is a risk factor for these cancers.
There is some evidence that H. pylori may also help prevent some childhood diseases, such as asthma. It may also prevent adult diseases, such as esophageal adenocarcinoma. More research is needed to confirm these findings.
Testing for H. pylori can be done using a variety of tools.
The urea breath test (UBT) is a non-invasive tool used to detect H. pylori infection. It is very good at detecting H. pylori. In Canada, UBT is the preferred non-invasive test for H. plylori infection.
A blood test (serology) detects specific antibodies to H. pylori, which the immune system develops in response to the bacterium. The blood test shows if someone has been exposed to H. pylori. A positive test indicates an infection is present or the person had an infection in the past.
Some tests detect H. pylori antigensantigensA foreign substance that stimulates the immune system to produce antibodies against it. in stool. Although stool antigen testing is accurate and easy to do, it is not as good at finding H. pylori as the other tests.
In certain situations, an upper GI endoscopy (gastroscopy) is done to diagnose H. pylori infection. During endoscopy, the doctor takes biopsies of the stomach lining. These samples are used to confirm a diagnosis of H. pylori, detect complications associated with H. pylori infection (such as suspected peptic ulcer) or rule out other health problems.
The Canadian Helicobacter Study Group (CHSG) developed guidelines for the care of Canadians with H. pylori infection, including children and adults. Routine testing for H. pylori is not recommended if an adult or child does not have any symptoms (asymptomatic) and does not have a past history of peptic ulcer disease. Most experts agree that the current evidence does not support widespread testing for and treating H. pylori infection.
However, there is evidence to support testing and treating H. pylori in certain high-risk individuals.
Japan, Korea and Matsu Island in Taiwan continue to have a high incidence of H. pylori infection and gastric cancer. These countries have population-based screening programs to find and treat H. pylori infection.
People infected with H. pylori are usually given a course of triple therapy that lasts 7–14 days.
H. pylori infection usually responds to treatment. Treatment cures H. pylori infection in 80%–90% of people.
There is not enough evidence to support treating children for H. pylori infection to prevent stomach cancer later in life.
The source of H. pylori is not yet known, so there aren’t specific recommendations for avoiding infection. In general, it is always wise for you to:
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