Master Chronic Gastritis with Picmonic for Medicine

Type A chronic gastritis, also called autoimmune atrophic gastritis, typically occurs in the fundus and body of the stomach. This type is characterized by an autoimmune response directed toward parietal cells in the stomach, which produce intrinsic factor. Loss of these cells leads to achlorhydria and pernicious anemia.

Type A chronic gastritis occurs in the fundus and body of the stomach as opposed to type B gastritis which occurs in the antrum. The fundus is the top most part of the stomach and marked off by a plane passing through the cardiac orifice horizontally.

Type A gastritis is characterized by the invasion of gastric tissue by self-reactive lymphocytes, leading to destruction of parietal cells. This also leads to the production of autoantibodies that attack both parietal cells and intrinsic factor. In addition, type A gastritis is associated with other autoimmune diseases such as type 1 diabetes.

Parietal cells are stomach epithelial cells that secrete gastric acid and intrinsic factor in response to acetylcholine, histamine, and gastrin. Self-reactive lymphocytes cause destruction of these cells in autoimmune gastritis. This also leads to autoantibodies against parietal cells and intrinsic factor, causing decreased acid secretion and pernicious anemia.

Pernicious anemia is a megaloblastic anemia caused by the loss of gastric parietal cells, which secrete hydrochloric acid, and intrinsic factor. Intrinsic factor is necessary for the proper absorption of vitamin B12 in the ileum. Loss of vitamin B12 leads to megaloblastic anemia.

Achlorhydria refers to absent production of gastric acid in the stomach. In type A gastritis, it is caused by destruction of parietal cells, which secrete gastric acid and intrinsic factor. Achlorhydria leads to impaired protein digestion due to inactivation of the enzyme pepsin, which is dependent on low gastric pH for activation. Decreased acid production also makes individuals more susceptible to bacterial overgrowth and infections.

Type B chronic gastritis is more common and strongly associated with Helicobacter pylori in the antrum of the stomach. Helicobacter pylori is a gram negative bacteria that burrows below the stomach's mucus layer and produces urease, which breaks down urea in the stomach to ammonia. The ammonia helps neutralize gastric acid and create an alkaline environment which leaves the stomach susceptible to damage.

Type B gastritis is the most common type of chronic gastritis.

Type B chronic gastritis is more common and strongly associated with Helicobacter pylori in the antrum of the stomach. Helicobacter pylori is a gram negative bacteria that burrows below the stomach's mucus layer and produces urease, which breaks down urea in the stomach to ammonia. The ammonia helps neutralize gastric acid and create an alkaline environment which leaves the stomach susceptible to damage.

H. pylori typically infects the antrum of the stomach, which is the initial portion of the pyloric region of the stomach. Therefore, Type B chronic gastritis affects the antrum of the stomach.

Mucosal-associated lymphoid tissue (MALT) lymphoma is a non-Hodgkin's lymphoma that can occur in the stomach, small bowel, salivary glands, thyroid and elsewhere in the body. It is associated with chronic immune responses to H. pylori and can be a complication of prolonged type B chronic gastritis.

Individuals with HIV/AIDS are more susceptible to chronic gastritis.

Crohn's disease is a type of inflammatory bowel disease that can affect any part of the gastrointestinal tract and cause a wide variety of symptoms including bloody diarrhea, weight loss, skin rashes, and uveitis. Individuals with Crohn's disease are more susceptible to chronic gastritis.