Helicobacter pylori

Snapshot

• A 54-year-old man presents to his primary care physician for an annual checkup. He reports having intermittent epigastric discomfort. He reports that the symptoms often improve after eating and that he has some bloating after big meals. He denies any fevers, chills, nausea or vomiting. He also denies having any blood in his stools. His physical exam is unremarkable. A urea breath test is arranged and the results are positive. He is started on triple therapy for eradication of the infection.

Introduction

• Classification
  • Helicobacter pylori 
    • gram-negative, spiral-shaped (comma-shaped), catalase-positive, urease-positive, oxidase-positive rod with motile flagella 
    • transmission
      • oral to oral
      • fecal to oral
    • causes chronic gastritis, which can lead to
      • peptic ulcer disease, particularly in the duodenum
      • mucosa-associated lymphoid tissue (MALT) lymphoma
      • gastric adenocarcinoma
• Epidemiology
  • incidence
    • very common
  • demographics
    • infections are often acquired during childhood
  • risk factors
    • smoking
    • nonsteroidal anti-inflammatory drug (NSAID) use
• Pathogenesis
  • the bacteria produces urease, which produces ammonia and results in an alkaline environment 
    • the ammonia allows the bacteria to survive in the acidic gastric environment
  • the bacteria colonize the antrum of the stomach
  • mucosal inflammation leads to atrophy
  • hypochloridia causes ↑ gastrin
  • ↑ gastrin from G cells in the stomach and duodenum
    • ↑ gastric acid secretion and growth of gastric mucosa
• Prognosis
  • very good prognosis with treatment
• recurrence may occur

Presentation

• Symptoms
  • dyspepsia
    • belching
    • postprandial bloating
    • heartburn
  • epigastric pain
    • may cause nighttime awakening
    • relief with food or antacids
• fullness

Studies

• Labs
  • urea breath test 
    • administer ¹³C urea
      • test for ammonia + ¹³C-CO₂ exhaled
    • may have false negatives when patients are exposed to H. pylori treatments such as proton pump inhibitors, histamine-2 (H₂) blockers, bismuth, and antibiotics that either reduce bacterial load or are anti-secretory, reducing the amount of urea produced
    • most accurate testing
  • stool antigen test
• Endoscopy with gastric biopsy  
  • histology with silver stain or immunohistochemical staining
    • H. pylori infection
    • inflammation
    • intestinal metaplasia
    • atrophy
• Making the diagnosis
  • based on clinical presentation and noninvasive tests such as urea breath test or stool antigen test
• endoscopy can also be used to diagnose

Differential

• Peptic ulcer disease from other causes
  • distinguishing factors
    • associated with NSAIDs use
• may also have Zollinger-Ellison syndrome

Treatment

• Management approach 
  • eradication therapy is beneficial for patients with peptic ulcer disease, chronic gastritis,
• Medical
  • triple therapy
    • indications
      • no history of previous macrolide exposure
      • no local resistance of H. pylori clarithromycin resistance
    • drugs
      • proton pump inhibitor
      • clarithromycin
      • amoxicillin or metronidazole
  • quadruple therapy
    • indication
      • history of macrolide exposure or penicillin allergy
    • drugs
      • proton pump inhibitor
      • bismuth subcitrate
      • metronidazole
• tetracycline

Complications

• Malignancies
  • gastric adenocarcinoma
  • MALT lymphoma
• Iron deficiency anemia
• Immune thrombocytopenia