Atrophic gastritis is a process of chronic

inflammation Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...

of the

gastric mucosa The gastric mucosa is the mucous membrane layer of the stomach, which contains the glands and the gastric pits. In humans, it is about 1 mm thick, and its surface is smooth, soft, and velvety. It consists of simple columnar epithelium, lamin ...

of the

stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...

, 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 Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid Acid strength is the tendency of an acid, symbol ...

pepsin Pepsin is an endopeptidase that breaks down proteins into smaller peptides. It is produced in the gastric chief cells of the stomach lining and is one of the main digestive enzymes in the digestive systems of humans and many other animals, w ...

, and

intrinsic factor Intrinsic factor (IF), cobalamin binding intrinsic factor, also known as gastric intrinsic factor (GIF), is a glycoprotein produced by the parietal cells (in humans) or chief cells (in rodents) of the stomach. It is necessary for the absorption ...

is impaired, leading to digestive problems. The most common are vitamin B₁₂ deficiency possibly leading to

pernicious anemia Pernicious anemia is a type of vitamin B12 deficiency anemia, a disease in which not enough red blood cells are produced due to the malabsorption of vitamin B12. Malabsorption in pernicious anemia results from the lack or loss of intrinsic fa ...

; and

malabsorption Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety ...

of iron, leading to

iron deficiency anaemia Iron-deficiency anemia is anemia caused by a lack of iron. Anemia is defined as a decrease in the number of red blood cells or the amount of hemoglobin in the blood. When onset is slow, symptoms are often vague such as feeling tired, weak, shor ...

. It can be caused by persistent infection with ''

Helicobacter pylori ''Helicobacter pylori'', previously known as ''Campylobacter pylori'', is a gram-negative, microaerophilic, spiral (helical) bacterium usually found in the stomach. Its helical shape (from which the genus name, helicobacter, derives) is though ...

'', or can be

autoimmune In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". P ...

in origin. Those with autoimmune atrophic gastritis (''Type A gastritis'') are statistically more likely to develop

gastric carcinoma Stomach cancer, also known as gastric cancer, is a cancer that develops from the lining of the stomach. Most cases of stomach cancers are gastric carcinomas, which can be divided into a number of subtypes, including gastric adenocarcinomas. Lymph ...

Hashimoto's thyroiditis Hashimoto's thyroiditis, also known as chronic lymphocytic thyroiditis and Hashimoto's disease, is an autoimmune disease in which the thyroid gland is gradually destroyed. Early on, symptoms may not be noticed. Over time, the thyroid may enlarg ...

, and

achlorhydria Achlorhydria and hypochlorhydria refer to states where the production of hydrochloric acid in gastric secretions of the stomach and other digestive organs is absent or low, respectively. It is associated with various other medical problems. Sig ...

. Type A gastritis primarily affects the fundus (body) of the stomach and is more common with

. Type B gastritis primarily affects the

antrum ''This is a disambiguation page for the biological term. For the 2018 horror movie, see Antrum (film)'' In biology, antrum is a general term for a cavity or chamber, which may have specific meaning in reference to certain organs or sites in the bod ...

, and is more common with ''H. pylori'' infection.

Signs and symptoms

Some people with atrophic gastritis may be asymptomatic. That said, symptomatic patients are mostly females and signs of atrophic gastritis are those associated with iron deficiency: fatigue,

restless legs syndrome Restless legs syndrome (RLS), also known as Willis-Ekbom disease (WED), is generally a long-term disorder that causes a strong urge to move one's legs. There is often an unpleasant feeling in the legs that improves somewhat by moving them. This ...

, brittle nails, hair loss, impaired immune function, and impaired wound healing. And other symptoms, such as delayed gastric emptying (80%), reflux symptoms (25%), peripheral neuropathy (25% cases), autonomic abnormalities, and memory loss, are less common and occur in 1%–2% of cases. Other 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 will be found at a younger age and many years before the development of 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 (AMAG) is a result of the immune system attacking the parietal cells. Environmental metaplastic atrophic gastritis (EMAG) 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 (AMAG) is an inherited form of atrophic gastritis characterized by an immune response directed toward parietal cells and intrinsic factor. The presence of serum antibodies to parietal cells and to intrinsic factor are characteristic findings. The autoimmune response subsequently leads to the destruction of parietal cells, which leads to profound

Achlorhydria Achlorhydria and hypochlorhydria refer to states where the production of hydrochloric acid in gastric secretions of the stomach and other digestive organs is absent or low, respectively. It is associated with various other medical problems. Sig ...

(and elevated

gastrin Gastrin is a peptide hormone that stimulates secretion of gastric acid (HCl) by the parietal cells of the stomach and aids in gastric motility. It is released by G cells in the pyloric antrum of the stomach, duodenum, and the pancreas. Gastrin ...

levels). The inadequate production of intrinsic factor also leads to vitamin B₁₂ malabsorption and

. AMAG is typically confined to the gastric body and fundus. Achlorhydria induces G cell (gastrin-producing) hyperplasia, which leads to hypergastrinemia. Gastrin exerts a trophic effect on enterochromaffin-like cells (ECL cells are responsible for

histamine Histamine is an organic nitrogenous compound involved in local immune responses, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Since histamine was discovered in ...

secretion) and is hypothesized to be one mechanism to explain the malignant transformation of ECL cells into

carcinoid A carcinoid (also carcinoid tumor) is a slow-growing type of neuroendocrine tumor originating in the cells of the neuroendocrine system. In some cases, metastasis may occur. Carcinoid tumors of the midgut (jejunum, ileum, appendix, and cecum) ...

tumors in AMAG.

Diagnosis

Detection of APCA(Antiparietal cell antibody), anti-intrinsic factor antibody (AIFA) and ''

'' (HP) antibodies in conjunction with serum gastrin are effective for diagnostic purposes. File:Histopathology of antral mucosa with atrophy.png, Histopathology of antral mucosa with atrophy. H&E 10x. Antral gastric mucosa with accentuated atrophy because replacement by extensive intestinal metaplasia. File:Histopathology of fundic mucosa with atrophy.png, Histopathology of fundic mucosa with atrophy. H&E 10x; square 20x. Fundic-corporal gastric mucosa with extensive loss of gastric glands, partially replaced by pseudo-pyloric metaplasia.

Classification

The notion that atrophic gastritis could be classified depending on the level of progress as "closed type" or "open type" was suggested in early studies, but no universally accepted classification exists as of 2017.

Treatment

Supplementation of

folic acid Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and ...

in deficient patients can improve the histopathological findings of chronic atrophic gastritis and reduce the incidence of gastric cancer.

References

External links

{{Digestive system diseases Aging-associated diseases Autoimmune diseases Stomach disorders