Harvey's Garden

Gastritis

3 min read

  • Patho/Etiology
    • Acute (Erosive) Gastritis: Sudden inflammation of the gastric mucosa, often with neutrophilic infiltration.
      • Causes: NSAIDs (inhibit prostaglandins, reducing mucosal protection), alcohol, smoking, severe stress (e.g., burns Curling’s ulcer, brain injury Cushing’s ulcer), and initial H. pylori infection.
    • Chronic (Non-Erosive) Gastritis: Long-term inflammation leading to mucosal atrophy and metaplasia, primarily with mononuclear cell infiltration (lymphocytes, plasma cells).
      • Type A (Autoimmune)
        • Site: Body and Fundus. t
        • Mech: Autoimmune destruction of Parietal cells & Intrinsic Factor.
        • Sequelae:
          • Achlorhydria: ↓ Acid → ↑ Gastrin (loss of feedback).
          • Pernicious Anemia: ↓ Intrinsic Factor → B12 deficiency.
        • Risk: Gastric Adenocarcinoma.
      • Type B (Bacterial)
        • Site: Antrum. t
        • Mech: H. pylori infection (Urease positive).
        • Sequelae:
          • D-cells destruction in antrum → ↓ Somatostatin → ↑ Gastrin → ↑ Acid → Duodenal ulcers.
          • Chronic inflammation → Intestinal metaplasia.
        • Risk: MALT Lymphoma, Gastric Adenocarcinoma.
  • Clinical Presentation
    • Acute: Often presents with epigastric pain, N/V, and anorexia. In severe cases, it can cause hematemesis or melena (erosive gastropathy).
    • Chronic: Can be asymptomatic or cause vague dyspepsia and abdominal discomfort.
      • Autoimmune: Patients may show symptoms of pernicious anemia (megaloblastic anemia) and neurologic deficits due to B12 deficiency (e.g., peripheral neuropathy). May also present with iron deficiency anemia.
  • Diagnosis
    • Endoscopy with biopsy: Gold standard to visualize inflammation, erosions, and atrophy, and to obtain tissue for histology.
    • H. pylori testing: Urea breath test or stool antigen test for active infection. Serology is less useful for confirming active infection.
    • Labs:
      • Autoimmune gastritis: Look for anti-parietal cell and anti-intrinsic factor antibodies, ↓ Vitamin B12 levels, and ↑ gastrin (due to achlorhydria).
      • Anemia: CBC may show microcytic anemia (Fe deficiency) or macrocytic anemia (B12 deficiency).
  • DDx (Differential Diagnosis)
    • Peptic Ulcer Disease (PUD): More localized, deeper mucosal defect. Duodenal ulcer pain often improves with food, while gastric ulcer pain worsens with food.
    • GERD: Characterized by retrosternal burning (heartburn) and regurgitation, worse when supine.
    • MI: Must be ruled out, especially with epigastric pain radiating to the arm/jaw, associated with SOB, and EKG changes.
    • Pancreatitis: Epigastric pain radiating to the back, with elevated lipase/amylase.
    • Gastric Cancer: Consider in patients with alarm symptoms (weight loss, anemia, dysphagia), especially in chronic gastritis.
  • Management/Treatment
    • General: Remove offending agents like NSAIDs and alcohol.
    • Acid Suppression: PPIs (e.g., omeprazole) or H2 blockers.
    • H. pylori Eradication: Triple therapy (PPI + clarithromycin + amoxicillin/metronidazole) or Quadruple therapy (PPI + bismuth + metronidazole + tetracycline).
    • Autoimmune Gastritis: Lifelong Vitamin B12 supplementation (parenteral).
  • Key Associations/Complications
    • PUD: Chronic gastritis is a major risk factor.
    • Gastric Adenocarcinoma: Increased risk with both autoimmune and H. pylori-associated chronic atrophic gastritis due to intestinal metaplasia.
    • MALT Lymphoma: Strongly associated with chronic H. pylori infection. t
    • Neuroendocrine Tumors (Carcinoid): A risk in autoimmune gastritis due to G-cell hyperplasia from chronic achlorhydria and elevated gastrin.

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