Makindo Medical Notes

🎯 Treatment of H. pylori aims to eradicate infection, reduce peptic ulcer disease and bleeding risk, and prevent recurrence, gastric cancer, and MALT lymphoma.

📖 About

• Discovered by Barry Marshall & Robin Warren in 1982 🧪.
• Most common cause of peptic ulceration, though many carriers are asymptomatic.
• Present in ~95% of duodenal ulcers and 70–80% of gastric ulcers.
• NSAIDs + H. pylori = 🔥 high ulcer risk.
• Associated with acute/chronic gastritis, gastric adenocarcinoma, and MALT lymphoma (regresses after eradication in many cases).

🔬 Electron Microscopy

🌍 Source

• Spread mainly person-to-person → oral–oral or faeco–oral.
• More common in older adults and in lower socioeconomic groups.
• Humans are the main reservoir (occasionally found in cats 🐈).

⚙️ Characteristics

• Spiral-shaped, Gram-negative, highly motile bacillus.
• Microaerophilic with 4–6 unipolar flagella.
• Urease production → breaks down urea to ammonia → neutralises gastric acid locally.
• Lives beneath gastric mucous layer and adheres to epithelial cells.

🧨 Virulence

• Causes neutrophilic gastritis.
• CagA gene linked to severe disease and higher gastric cancer risk.
• Produces urease and VacA toxin → epithelial injury.

🩺 Pathogenicity

• Antral gastritis → achlorhydria + ↑ gastrin + ↑ acid secretion.
• Chronic duodenal ulcers (95% cases) & gastric ulcers (70–80%).
• Gastric cancer: adenocarcinoma (80% linked to H. pylori).
• MALT lymphoma: may regress after eradication.

🧪 Investigations

• 🩸 Serology: Detects IgG → cannot distinguish past from current infection.
• 💨 Urea Breath Test (13C/14C): Most accurate non-invasive test.
• 💩 Stool Antigen Test (SAT): Confirms active infection.
• 🔬 Histology + biopsy urease (CLO test): High sensitivity/specificity.
• 🧫 Culture: Gold standard but slow (used for resistance testing).

💊 Management (UK)

• First-line (Triple Therapy): for 1 week
  • Clarithromycin 500 mg BD
  • Amoxicillin 1 g BD (or Metronidazole if penicillin-allergic)
  • PPI (Omeprazole 20 mg BD or equivalent)
• Second-line (if failure or resistance):
  • Metronidazole 400 mg TDS
  • Amoxicillin 1 g BD
  • PPI BD
• Treatment is indicated for:
  • Peptic ulcer disease (gastric & duodenal)
  • MALT lymphoma
  • Post-bleed ulcers & atrophic gastritis
• Routine screening for asymptomatic carriers is not recommended in low-risk groups.

📚 References

• Review on H. pylori
• BNF: H. pylori Infection