Makindo Medical Notes

Treatment aims to eradicate *H. pylori*, reduce the risk of peptic ulcer disease, ulcer bleeding, gastric malignancy, and recurrence of gastritis and peptic ulcers.

About

• First discovered by Barry Marshall in 1982.
• The most common cause of peptic ulceration, though many carriers remain asymptomatic.
• Present in 95% of duodenal ulcers and 70–80% of gastric ulcers.
• NSAIDs may exacerbate ulceration if co-infection with *H. pylori* exists.
• Associated with acute and chronic gastritis, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma.

Electron Microscopy

Source

• Likely spreads person-to-person through oral or faeco-oral routes.
• More common in older patients and in lower socioeconomic environments.
• The primary reservoir is humans, although *H. pylori* has also been found in cats.

Characteristics

• Spiral-shaped, gram-negative, highly motile bacillus.
• Microaerophilic organism with 4 to 6 unipolar flagella and urease production.
• Adheres to gastric epithelial cells and resides beneath the mucous layer of the stomach lining.

Virulence

• Triggers localized neutrophilic gastritis.
• Presence of the *cagA* gene (cytotoxin-associated gene) is linked to more severe disease manifestations.

Pathogenicity

• Antral gastritis leading to achlorhydria, raised gastrin levels, and increased acid secretion.
• Chronic duodenal ulcers in over 95% of cases.
• Gastric ulcers in over 80% of cases.
• Associated with gastric adenocarcinoma (over 80%) and MALT lymphoma, which may regress with *H. pylori* eradication.

Investigations

• Serology: Detects IgG antibodies but cannot differentiate between current or past infection.
• Carbon urea breath test (using 13C or 14C isotopes): Urease converts urea to labeled carbon dioxide, which is detected in expired breath—most accurate test.
• Stool Helicobacter Antigen Test (SAT): Can confirm active infection.
• Histology: High sensitivity and specificity when biopsies are examined under microscopy.
• Rapid urease tests (CLO test): Performed during endoscopy—cheap, fast, and specific.
• Culture: The gold standard, but slow and labor-intensive.

Management

• First-line treatment:
  • Clarithromycin 500 mg twice daily for 1 week.
  • Amoxicillin 1 g twice daily for 1 week.
  • Omeprazole 20 mg twice daily for 2 weeks.
• Second-line treatment:
  • Metronidazole for 1 week.
  • Amoxicillin 1 g twice daily for 1 week.
  • Omeprazole 20 mg twice daily for 2 weeks.
• Treatment is indicated for peptic ulcer disease and MALT lymphoma.
• Routine screening for asymptomatic *H. pylori* infection is not recommended in low-risk patients.

References

• A Review on Helicobacter Pylori: Its Biology, Complications, and Management
• Helicobacter Pylori in the BNF