Clinical Pearls & Morning Reports
Published March 20, 2019
Helicobacter pylori infection is a common, usually lifelong, infection that is found worldwide. In the United States, prevalence varies regionally and according to ethnic group or socioeconomic status. Read the latest Clinical Practice article here.
Q: When is noninvasive testing for H. pylori infection recommended?
A: Noninvasive testing is recommended in patients for whom endoscopy is not indicated but who have conditions associated with the infection (e.g., history of peptic ulcer disease, unexplained iron-deficiency anemia, or immune thrombocytopenia) or who are considered to be at increased risk for infection or complications of infection (e.g., patients with long-term use of nonsteroidal antiinflammatory drugs or aspirin).
Q: Is gastric cancer the only cancer associated with H. pylori infection?
A: On the basis of compelling evidence, the World Health Organization has classified H. pylori as a carcinogen leading to gastric adenocarcinoma. Another neoplastic disease that is caused by chronic H. pylori infection is gastric mucosa–associated lymphoid tissue lymphoma (MALToma) — a condition that is much less common than peptic ulcer disease or gastric adenocarcinoma.
A: Noninvasive tests for active infection include the stool antigen test and urea breath test. The 2017 guidelines of the American College of Gastroenterology (ACG) and the Houston Consensus do not recommend either test preferentially, but both note the substantially lower cost of stool antigen testing. In contrast, the Maastricht V–Florence guidelines recommend the urea breath test over stool antigen testing because of its somewhat greater accuracy for detecting infection. Serologic testing for H. pylori IgG is no longer recommended for the diagnosis of infection in areas in which the prevalence is 30% or less; the current prevalence in the United States is estimated to be 30%. Because antibodies persist for several years, serologic testing for H. pylori IgG has a specificity of less than 80% for active H. pylori infection, and repeat serum IgG testing is not useful for assessing eradication.
A: Guidelines recommend that decisions regarding therapy routinely take into account whether the patient has had any previous exposure to macrolide antibiotics (e.g., clarithromycin, azithromycin, and erythromycin) and whether the patient has an allergy to penicillin. Other factors in decision making include other allergies, potential adverse reactions (e.g., gut symptoms and also tendinitis with fluoroquinolones, which is a particular concern in older men), costs, insurance coverage, and availability. An important recommendation in the 2017 ACG guidelines, which represented a considerable change from the 2007 guidelines, was that all infected persons should be treated and then retested to assess for successful eradication. Should retreatment be indicated, a different regimen that avoids repetitive use of the same antibiotic agents is recommended.