Chronic gastritis is a long-lasting, recurring inflammation of the stomach’s lining, caused by a number of factors, which results in gradual transformation of gastric glandular cells into fibrous and intestinal tissues, impairing the stomach’s function.
Chronic gastritis is often asymptomatic (does not produce any symptoms), which makes it very hard to detect. The main forms of chronic gastritis are:
Type A gastritis
Type A gastritis (autoimmune gastritis) - this type of gastritis occurs due to the fact that body’s own immune cells attack and destroy parietal cells (acid secreting cells) of the stomach, which leads to:
- Achlorhydria and hypochlorhydia – complete absence of stomach acid or substantial decrease in its production. This condition in turn causes are reflectory increase in gastrin levels (which normally would increase acid production, but there is not enough parietal (gastric) cells to do so) which promotes gastric cell hyperplasia.
- Increased chance of cancer – gastric cell hyperplasia can lead to the appearance of gastric carcinoid tumors if the type A gastritis persists for a long period of time and is left untreated.
- Megaloblastic anemia – is an anemia caused by a deficiency or low absorption of vitamin B12. This happens due to decrease in intrinsic factor(allows for binding and absorption of vitamin B12), which is normally secreted by parietal cells. This happens to be the number one reason for Megaloblastic anemia.
- A decrease in the acidity of the stomach’s content can slow down the food’s digestion. However, this can be easily combated using appropriate drug therapy. Unfortunately this therapy has to be continued for the rest of patient’s life, since there is no way to restore acid secreting cells of the stomach.
Type B gastritis
Type B gastritis (bacteria-induced gastritis) - occurs as a result of Helicobacter pylori infection. This is the most common type of gastritis, since the majority of people are infected by Helicobacter pylori. Usually, this type of gastritis does not produce any symptoms; however, a small percentage of people develop peptic ulcers as a result of it. People with type B gastritis are more likely to develop adenocarcinoma and in rarer cases - B-cell gastric lymphoma, as a result of constant inflammatory process.
Type C gastritis
Type C gastritis (chemically induced gastritis) – is usually caused by irritation of gastric mucosa by bile or by Non-steroidal anti-inflammatory drugs (NSAIDs).
- Biliary reflux gastritis – a repeated exposure of stomach’s lining to bile can result in mucosal injury, which is characterized by striking erythema (redness), pronounced edema (swelling), and occasional erosions which may results in hemorrhage (bleeding). This condition is often experienced by patient who went through partial gastric resection.
- Gastritis caused by NSAIDs – is caused by the ability of NSAIDs to suppress prostaglandins which play a key role in the protection of the gastric mucosa from the corrosive effect of hydrochloric acid.
Other types of chronic gastritis
- Giant hypertrophic gastritis (Ménétrier disease) – is characterized by excessive growth of gastric mucosa, creating massive gastric folds and production of an excessive amount of mucous, which leads to protein loss, while the acid production is relatively low. This is a precancerous condition.
- Rugal hyperplastic gastritis – is believed to be caused by Helicobacter pylori and is characterized by hyperrugosity (and excessive amount of wrinkles) and atrophy of the stomach’s mucous layer. Gastric carcinoma is often associated with this condition.
- Crohn’s disease of the stomach – although Crohn’s disease usually affects the terminal part of ileum and the proximal part of colon, it can also affect the stomach, resulting in chronic inflammation, which is usually asymptomatic. Unlike regular gastritis, Crohn’s disease of the stomach produces mucosal nodularity (also known as “cobblestoning”) – which is characterized by ulcerations and thickened folds.
- Eosinophilic gastritis – is characterized by substantial eosinophilic infiltration of the stomach’s walls. This condition happens as a result of hyperergic allergic reaction to various pathogens. Usually such patients also suffer from food and seasonal allergies. Many such patients also suffer from asthma, eczema, and other atopic conditions.
- Radiation-induced gastritis – radiotherapy focused on the upper abdomen might result in damage to the stomach’s wall. This damage is characterized by erythema, prominence of gastric folds and friability. Close inspection of erythema reveals that it consists of a multitude of red dots separated by pale furrows. Ulceration, caused by exposure to radiation, tends to heal very slowly, creating scar tissue.
- Collagenous gastritis – is characterized by deposition of collagen under the gastric mucosa. The etiology of this condition is unknown.
- Immunodeficiency – leads to idiopathic (cause is unknown) chronic gastritis in about 40 percent of the cases. This gastritis is characterized by erythema and excessive production of mucous. Unlike in other types of gastritis, plasma cells cannot be detected in the inflammatory infiltrate, while the systemic gastric autoantibodies are also absent.