DESCRIPTION

Macroscopic or microscopic inflammation of mucosa of stomach

EPIDEMIOLOGY

• 8 out of every 1,000 people are estimated to have gastritis.
• Incidence increases after 10 years of age.
• Classification:
  • Based on duration: acute, chronic
  • Based on pathology: erosive, hemorrhagic, lymphocytic, atrophic, eosinophilic, etc.

ETIOLOGY

• Infections
  • Helicobacter pylori: most common; acute infection results in neutrophilic infiltrate. Chronic infection leads to lymphocytes and plasma cell infiltration; may have consequences such as gastric carcinoma
  • Helicobacter heilmannii: from cats; associated with carcinoma and mucosal associated lymphoma
  • Mycobacterium tuberculosis: rare, granulomas on histology
  • Bacillus cereus: food poisoning; can cause acute necrotizing gastritis
  • Cytomegalovirus: more common in immunocompromised patients; can be associated with Ménétrier disease (hypertrophic gastric folds, hypoalbuminemia)
  • Other viruses such as herpes simplex virus (HSV), human herpesvirus (HHV)-7, varicella, and Epstein-Barr virus are less common.
  • Fungal: more common in immunocompromised patients; Candida albicans is the most common. Other causes include Cryptosporidium and Aspergillus (invasive gastritis).
  • Parasites: Anisakis simplex (sushi, sashimi), Eustrongylides wenrichi (infected fish)
• Reactive gastritis
  • Caused by reaction to ischemia, chemicals, or drugs; may have mucosal edema and paucity of inflammatory infiltrate on histology (in which case referred to as gastropathy)
  • Stress—sepsis, hypoperfusion, CNS disease, mechanical ventilation, coagulopathy; major surgery; severe burns; multiorgan failure; severe trauma; usually occurs within 24 hours of trigger
  • Radiation, bleeding, perforation, fibrosis, obstruction
  • Traumatic: nasogastric tubes, forceful vomiting
  • Caustic ingestions (e.g., lye, strong acids, pine oil)
  • Ethanol
• Drug-induced
  • Nonsteroid anti-inflammatory drugs (NSAIDs)
  • Corticosteroids
  • Valproate
  • Iron (rare)
  • Calcium salts (rare)
  • Potassium chloride (rare)
  • Antibiotics (rare)
• Eosinophilic
  • Scleroderma
  • Parasites
  • Part of eosinophilic gastroenteritis
  • Allergic gastroenteropathy
  • Protein sensitivity (e.g., cow’s milk protein allergy)
• Lymphocytic
  • Celiac disease, Crohn disease (Up to 40% of Crohn patients have gastroduodenal involvement. Gastric Crohn disease may manifest itself as highly focal, non-H. pylori, nongranulomatous gastritis.)
• Endocrine
  • Zollinger-Ellison syndrome: uncontrolled gastrin production from tumor
  • Systemic mastocytosis: increased histamine production
  • Hyperparathyroidism: increased gastrin secretion from hypercalcemia
• Idiopathic
• Other
  • Hypertrophic gastritis (Ménétrier disease)
  • Autoimmune gastritis
  • Collagenous gastritis