Helicobacter pylori Infection

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Helicobacter pylori Infection

  • Helicobacter pylori infection is a common, usually lifelong, infection that is found worldwide.
  •  Studies suggest that infection rates vary according to geographic region, but the number of infected people has persisted or even increased over the past three decades because of population growth and because of reinfection and recrudescence due to unsuccessful eradication.
  •  A less advantaged socioeconomic status is a risk factor for H. pylori infection because it is associated with more crowded living conditions that favor intrafamilial transmission.
  • Iatrogenic infection by means of endoscopes also occurs.
  • Testing for H. pylori is recommended in patients with peptic ulcer disease, gastric cancer, or gastric mucosa–associated lymphoid tissue lymphoma.
  • Other recommended indications for testing include dyspepsia, prolonged use of nonsteroidal antiinflammatory drugs or aspirin, unexplained iron-deficiency anemia, and immune thrombocytopenia.
  • Testing for H. pylori can be performed directly on biopsy specimens obtained during endoscopy or performed by means of the stool antigen test or urea breath test. Proton-pump inhibitors (PPIs) interfere with the detection of bacteria and must be discontinued before any testing is performed.
  • Several regimens are considered to be acceptable for initial treatment. The presence of an allergy to penicillin, previous exposure to macrolides, and high levels of macrolide resistance where the patient lives or has lived (if information is known) are relevant in choosing a regimen.
  • After treatment, it is essential to document clearance of the infection, typically by means of a stool antigen test or urea breath test performed 1 month after the completion of antibiotic therapy (again, while the patient is not taking a PPI).
  • Should retreatment be indicated, a different regimen that avoids repetitive use of the same antibiotic agents is recommended.
  • Although the majority of infected persons remain asymptomatic, infection has been directly linked to several conditions — in particular, peptic ulcer disease and nonulcer dyspepsia. Evidence (reviewed below) has shown that treatment to eradicate H. pylori can reduce the risks of both conditions,although the data are less consistent regarding nonulcer dyspepsia.
  • Gastric cancer has also been closely associated with the presence of H. pylori. In a study conducted in Japan, gastric cancer developed (over a mean follow-up of 7.8 years) in 2.9% of patients with peptic ulcer, dyspepsia, or gastric hyperplasia who had H. pylori infection, whereas no cases were detected in uninfected patients with these conditions.
  •  On the basis of compelling evidence, the World Health Organization (WHO) has classified H. pylori as a group 1 carcinogen leading to gastric adenocarcinoma In addition to Japan, areas with an increased incidence of gastric carcinoma attributable to this infection include the Middle East, Southeast Asia, the Mediterranean, Eastern Europe, Central America, and South America. Immigrants who grew up in regions of the world with a high incidence of H. pylori infection (e.g., Eastern Europe and East Asia) and who now reside in the United States or Western Europe are also at increased risk for gastric cancer. 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
  • Conditions outside the gastrointestinal tract have also been associated with H. pylori infection.
  • An observed association with coronary artery disease probably reflects shared risk factors, such as poverty and suboptimal nutrition.
  • Unexplained iron-deficiency anemia12 and immune thrombocytopenia have been associated with H. pylori infection; although the pathogenesis is not well understood, reports of successful treatment of H. pylori infection leading to an increased hemoglobin level or higher platelet count suggest causal relationships (see below).
  • Evidence to support benefits of treatment of H. pylori infection for the conditions for which screening is recommended derives from randomized trials and observational studies. A Cochrane review of randomized trials showed that the addition of a therapy designed to eradicate H. pylori in patients who tested positive for this infection led to a lower incidence of duodenal ulceration (in 34 trials) or gastric ulceration (in 12 trials) than no treatment The numbers of patients who would need to be treated for H. pylori infection in order to prevent a recurrent duodenal or gastric ulcer were 2 and 3, respectively. In another meta-analysis of clinical trials, the number of patients with H. pylori infection who would need to be treated for dyspepsia (number needed to treat, 13) was greater than that for peptic ulcer disease.소스:NEJM