Acute Gastritis:• Gastritis: inflammation of the gastric mucosa.• Diagnosis mostly histological.• Acute Gastritis:acute mucosal inflammatory process usually of a transient nature.• neutrophilic infiltration• Etiology:Heavy use of NSAID’s, particularly aspirinExcessive alcohol consumption&Heavy smoking
Treatment with cancer chemotherapeutic drugs Gastric irradiation or freezing Systemic bacterial or viral infections Severe stress& Mechanical trauma Ischemia, shock & uremia Distal gastrectomy.• Pathogenesis:increased acid secretion with back-diffusion, decreased production of bicarbonate buffer,reduced blood flow,disruption of the adherent mucus layer, direct damage to the epithelium.
• Morphology:the gastric mucosa demonstrates edema, neutrophilic infiltrates, mucosal erosions, and, if severe, ulceration & hemorrhage. FIGURE 17–13 B.Low-power microscopic view of focal mucosal disruption with hemorrhage; the adjacent mucosa is normal.
Chronic Gastritis:• Chronic gastritis is defined as the presence of chronic mucosal inflammatory changes leading eventually to mucosal atrophy and intestinal metaplasia, usually in the absence of erosions• Etiology:Chronic infection by H. pylori Immunologic,(in association with pernicious anemia)
Toxic,(alcohol &cigarette smoking) Postsurgical,(esp following antrectomy with gastroenterostomy) Motor and mechanical,(obstruction, bezoars& gastric atony)Radiation Granulomatous conditions (e.g., Crohn disease) Misc.—amyloidosis, graft-versus-host disease ,uremia.• Pathogenesis:
oChronic atrophic gastritis caused by H.pylori:• (1) Gram-negative, curved rod• (2) Produces urease, proteases, cytotoxins (a) Urease converts amino groups in proteins toammonia (b) Secretion products produce chronic gastritisand PUD,• (3) Colonizes mucus layer liningoAutoimmune atrophic gastritis:• Autoantibodies to parietal cells (H/K ATPase proton pump) and intrinsic factor
• Morphology:• Chronic inflammatory infiltrate(lymphocytes &/or plasma cells) in the lamina propria• Intestinal metaplasia(Precursor lesion for adenocarcinoma)• Intestinal atrophy• Epithelial dysplasia• FIGURE 17–14 Chronic gastritis, showing partial replacement of the gastric mucosal epithelium by intestinal metaplasia (upper left) and inflammation of the lamina propria (right) containing lymphocytes and plasma cells.