What  is H. pylori infection?

H. pylori infection is a condition that can sometimes cause pain in the upper belly, bloating, nausea, or vomiting.

H. pylori infection occurs when a type of bacteria called H. pylori infects a person’s stomach or duodenum. The duodenum is the first part of the small intestine

Many people have H. pylori infection. Most of the time, H. pylori infection does not lead to any problems or cause any symptoms.

But in some people, H. pylori infection leads to problems that can cause symptoms. These problems can include:

Doctors do not know why H. pylori infection leads to problems in some people and not others.

What are the symptoms of H. pylori infection?

Most people with H. pylori infection have no symptoms. But people who have ulcers can have symptoms that are caused by the ulcers. Common symptoms of ulcers can include:

Not all ulcers are caused by H. pylori infection. For example, people can get ulcers from taking certain pain-relieving medicines. But if you have the symptoms listed above, let your doctor or nurse know.

Is there a test for H. pylori infection?

 Yes. Doctors can do different tests to diagnose H. pylori infection. These can include:

Should I be tested for H. pylori infection?

You should be tested for H. pylori infection if you have symptoms and:

Sometimes, doctors test people who have no symptoms for H. pylori infection if they have a family history of stomach cancer. Doctors also sometimes test people with symptoms who have never had an ulcer.

I'm familiar with the cause-and-effect relationship between Helicobacter pylori infection and peptic ulcers. But is every peptic ulcer caused by H. pylori? And does peptic ulcer always develop in those infected with H. pylori?
No to both questions. In the United States, approximately 75% of peptic ulcers result from H. pylori infection. Aspirin and nonsteroidal antiinflammatory drugs (NSAIDs) cause most of the remaining 25%. In a few cases, ulcers are caused by Crohn's disease or a rare gastrin-secreting tumor (Zollinger-Ellison syndrome) or are of undetermined etiology.
Approximately 35% of the population in the United States are infected with H. pylori, but most infected persons do not have a peptic ulcer. The lifetime risk of a peptic ulcer developing in these patients is approximately one in five.

What is the relationship between gastritis and H. pylori?
Gastritis is a histologic diagnosis, not a clinical one. Chronic active gastritis, histologically characterized by a cellular inflammatory infiltrate, is caused by H. pylori infection. However, the relationship between the microscopic finding of chronic active gastritis and clinical symptoms is inconsistent. Consider the patient who reports to the emergency department with nonspecific upper abdominal pain and who is discharged with a diagnosis of gastritis. A more correct diagnosis would be dyspepsia

Are all gastric cancers caused by H. pylori?
Adenocarcinoma of the distal stomach is strongly associated with H. pylori infection. The cancer is eight times more likely to develop in persons with H. pylori infection than in those not infected.
Cancer of the proximal stomach appears to be a different disease, with an incidence similar to that of adenocarcinoma of the gastroesophageal junction. Although the incidence rates of adenocarcinoma of the distal stomach, H. pylori infection, and peptic ulcer disease are all decreasing, the incidence of cancer of the gastric cardia (the most proximal part of the stomach) is increasing.

Is it true that some gastric lymphomas can be cured by antibiotic treatment of H. pylori infection?
Unlike the small intestine, the stomach normally has no lymphoid tissue. In the presence of H. pylori infection, however, a neoplastic proliferation of B cells in the gastric mucosa may develop. This condition is called mucosa-associated lymphoid tissue (MALT) lymphoma. The dependence of these proliferating B cells on H. pylori is demonstrated by the fact that tumor regression may occur in as many as 80% of MALT lymphomas when the infection is eradicated.

How is H. pylori infection treated?

H. pylori infection is treated with medicines. Most people need to take 3 or more medicines for 1 to 2 weeks. These can include:

People who are diagnosed with H. pylori infection should get treated, because treatment can:

It is important to follow all your doctors’ instructions about taking your medicines. Let your doctor or nurse know if you have any side effects or problems with your medicines.

What happens after treatment?

 After treatment, most people have follow-up tests to check that the H. pylori infection has gone away. Follow-up tests can include:

Most of the time, H. pylori infection is cured with treatment. But sometimes, H. pylori infection is not cured with treatment. People who still have H. pylori infection after being treated might need to take medicines for another 2 weeks.