Acute Gastritis: Etiology and Morphology
Acute inflammation of the gastric mucosa develops under the influence of various damaging factors.
Main Causes:
- Acute intoxications: consumption of alcohol surrogates, chemical burns, and endogenous intoxication (e.g., in uremia).
- Infectious diseases: salmonellosis, cholera.
Depending on the nature of the injury, several morphological forms of inflammation are distinguished: catarrhal, hemorrhagic, and fibrinous. Corrosive (necrotic) gastritis is less common and typically occurs due to chemical burns or alcohol surrogate ingestion.
Most often, the acute process has a favorable outcome, with the normal mucosal structure fully restoring. However, in the necrotic form, severe complications can occur: massive hemorrhage from eroded submucosal vessels or gastric wall perforation leading to peritonitis.
Chronic Gastritis: Pathology Overview
Chronic gastritis is a long-standing inflammation of the mucosa that is invariably accompanied by impaired cellular renewal.
It is essential to understand that this is strictly a morphological phenomenon. The disease lacks a specific clinical picture, so an accurate diagnosis can only be made based on pathomorphological examination. This requires biopsies from two zones: the gastric body and the antrum.
The predictable outcome of prolonged inflammation is atrophy of the gastric glands. Functionally, this manifests as secretory failure, up to the complete cessation of gastric juice production (achylia).
Activity Assessment and the Sydney System
The universally accepted diagnostic standard is the Updated Sydney System (1996). It provides a comprehensive evaluation of the disease across three parameters: etiology, topographic distribution, and morphological changes.
A key parameter is the activity of chronic gastritis, which is determined by the presence of neutrophils within the epithelial layer or the lamina propria of the mucosa.
Infiltration Features:
- Neutrophils can invade the surface and pit epithelium.
- Accumulating within the lumen of the gastric pits, they form characteristic microscopic structures called foveolar abscesses.
- There is a strong correlation: in 90% of observations, the number of neutrophils in the mucosa directly reflects the density of Helicobacter pylori colonization.
The OLGA Classification
The OLGA (Operative Link for Gastritis Assessment) system was developed to refine the Sydney System. Its primary goal is to accurately assess the risk of malignant transformation and predict the reversibility of identified changes.
Key Innovations of the OLGA System:
- Refined Definition of Atrophy. Atrophy now encompasses not only a physical reduction in gland numbers but also intestinal metaplasia. This is because metaplastic cells lose their ability to perform the secretory function characteristic of that gastric zone.
- Separation of Concepts:
- Grade of chronic gastritis reflects the severity of inflammatory infiltration.
- Stage of chronic gastritis is an integrated assessment of mucosal atrophy across all sampled gastric compartments.
- Clinical Significance. Patients diagnosed with stage III or IV chronic gastritis are placed in a high-risk group: their probability of developing intestinal-type gastric cancer is increased 6-fold.