Gastritis

Gastritis is the inflammation of the gastric mucosa, which can be acute or chronic. It may lead to symptoms like abdominal pain, nausea, vomiting, and altered gastric function.

Epidemiology

• Prevalence: Gastritis is common, with estimates suggesting that about 50% of the global population is affected by some form of gastric inflammation at some point in their lives.
• Risk Factors:
  • Infectious Agents:
    • Helicobacter pylori infection is the most significant and prevalent cause, affecting approximately 50% of the global population.
  • Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): Regular use increases the risk of gastritis.
  • Alcohol Consumption: Heavy alcohol use can irritate the gastric mucosa.
  • Stress: Physical stress from illness or injury and emotional stress can contribute to acute gastritis.
  • Autoimmune Conditions: Autoimmune gastritis is associated with pernicious anemia and other autoimmune disorders.

Classification

1. Acute Gastritis: Characterized by a rapid onset of inflammation, often self-limiting.
   • Etiology: Commonly caused by infections (e.g., H. pylori), NSAIDs, alcohol, or stress.
2. Chronic Gastritis: A long-term condition that can lead to gastric atrophy and other complications.
   • Types:
     • Chronic Autoimmune Gastritis: Caused by an autoimmune response against gastric parietal cells, leading to decreased intrinsic factor and vitamin B12 deficiency.
     • Chronic Atrophic Gastritis: Associated with long-standing H. pylori infection and can progress to gastric cancer.

Pathophysiology

Gastritis involves the disruption of the gastric mucosal barrier, leading to inflammation. Key mechanisms include:

• Mucosal Injury: Due to NSAIDs, alcohol, or H. pylori, which damage the epithelial cells and expose underlying tissue.
• Inflammatory Response: Activation of immune cells (neutrophils and macrophages) leads to the release of cytokines and mediators, exacerbating inflammation.
• Gastric Acid Secretion: Altered secretion can result in further mucosal damage, especially in the presence of an irritant.

Clinical Presentation

• Symptoms:
  • Epigastric pain or discomfort
  • Nausea and vomiting
  • Loss of appetite
  • Bloating and indigestion
  • Hematemesis (in severe cases)
  • Melena (if there is significant mucosal damage)
• Signs:
  • Tenderness in the epigastric region
  • Possible signs of anemia in chronic cases (e.g., pallor, fatigue)

Diagnosis

1. History and Physical Examination: Assess risk factors, medication use, and symptoms.
2. Laboratory Tests:
   • Complete Blood Count (CBC): Look for anemia or leukocytosis.
   • Serum Gastrin Levels: Can be elevated in autoimmune gastritis.
   • Helicobacter pylori Testing:
     • Non-invasive tests: Urea breath test, stool antigen test.
     • Invasive tests: Endoscopic biopsy with histological examination or rapid urease testing.
3. Endoscopy:
   • Direct visualization of the gastric mucosa.
   • Biopsy for histological examination to assess the presence of H. pylori and rule out malignancy.

Management

1. Eradication of Helicobacter pylori:
   • First-Line Therapy: Triple therapy:
     • Proton Pump Inhibitor (PPI): Omeprazole 20 mg bid or esomeprazole 40 mg daily.
     • Antibiotic: Amoxicillin 1 g bid + clarithromycin 500 mg bid for 14 days.
   • Second-Line Therapy: If the first line fails, consider quadruple therapy (PPI, bismuth subsalicylate, tetracycline, metronidazole).
2. Symptomatic Relief:
   • PPIs: Reduce gastric acid secretion and promote mucosal healing.
     • Omeprazole: 20 mg daily for 4–8 weeks.
     • Lansoprazole: 30 mg daily.
   • Antacids: For immediate symptom relief.
   • H2-Receptor Antagonists: Ranitidine 150 mg bid or famotidine 20 mg bid for symptomatic control.
3. Lifestyle Modifications:
   • Dietary Changes: Avoid irritants (spicy foods, caffeine, alcohol, and NSAIDs).
   • Stress Management: Implement strategies to reduce psychological stress.
4. Management of Chronic Gastritis:
   • For autoimmune gastritis, monitor for vitamin B12 deficiency and supplement as needed (e.g., cyanocobalamin 1000 mcg IM monthly).
   • Regular follow-up for patients with chronic atrophic gastritis to assess for the risk of gastric cancer.

Complications

• Gastric Ulceration: Chronic gastritis can lead to the development of ulcers.
• Gastric Cancer: Chronic atrophic gastritis is a precursor to gastric malignancy, necessitating monitoring and surveillance.
• Vitamin B12 Deficiency: In autoimmune gastritis, leading to megaloblastic anemia and neurological symptoms.

Prognosis

• Acute Gastritis: Generally good; most cases resolve with appropriate management.
• Chronic Gastritis: Requires ongoing management; the risk of complications such as ulcers and gastric cancer necessitates regular follow-up.