Atrophic gastritis
Atrophic gastritis is a process of chronic inflammation of the gastric mucosa of the stomach, leading to a loss of gastric glandular cells and their eventual replacement by intestinal and fibrous tissues. As a result, the stomach's secretion of essential substances such as hydrochloric acid, pepsin, and intrinsic factor is impaired, leading to digestive problems. The most common are pernicious anemia possibly leading to vitamin B12 deficiency; and malabsorption of iron, leading to iron deficiency anaemia. It can be caused by persistent infection with Helicobacter pylori, or can be autoimmune in origin. Those with autoimmune atrophic gastritis are statistically more likely to develop gastric carcinoma, Hashimoto's thyroiditis, and achlorhydria.
Type A gastritis primarily affects the fundus of the stomach and is more common with pernicious anemia. Type B gastritis primarily affects the antrum, and is more common with H. pylori infection.
Signs and symptoms
Some people with atrophic gastritis may be asymptomatic. Symptomatic patients are mostly females and signs of atrophic gastritis are those associated with iron deficiency: fatigue, restless legs syndrome, brittle nails, hair loss, impaired immune function, and impaired wound healing. And other symptoms, such as delayed gastric emptying, reflux symptoms, peripheral neuropathy, autonomic abnormalities, and memory loss, are less common and occur in 1%–2% of cases. Psychiatric disorders are also reported, such as mania, depression, obsessive-compulsive disorder, psychosis, and cognitive impairment.Although autoimmune atrophic gastritis impairs iron and vitamin B12 absorption, iron deficiency is detected at a younger age than pernicious anemia.
Associated conditions
People with atrophic gastritis are also at increased risk for the development of gastric adenocarcinoma.Causes
Recent research has shown that autoimmune metaplastic atrophic gastritis is a result of the immune system attacking the parietal cells.Environmental metaplastic atrophic gastritis is due to environmental factors, such as diet and H. pylori infection. EMAG is typically confined to the body of the stomach. Patients with EMAG are also at increased risk of gastric carcinoma.
Pathophysiology
Autoimmune metaplastic atrophic gastritis is an inherited form of atrophic gastritis characterized by an immune response directed toward parietal cells and intrinsic factor.Achlorhydria induces G cell hyperplasia, which leads to hypergastrinemia. Gastrin exerts a trophic effect on enterochromaffin-like cells and is hypothesized to be one mechanism to explain the malignant transformation of ECL cells into carcinoid tumors in AMAG.