Autoimmune Gastritis: Understanding Type A Gastritis

What is Type A Gastritis?

Type A gastritis, also known as autoimmune gastritis, is a form of chronic atrophic gastritis. It occurs when the body's immune system mistakenly attacks the healthy cells in the stomach lining. This condition primarily affects the fundus and corpus of the stomach, leading to inflammation and eventual thinning of the gastric mucosa. One of the key characteristics of Type A gastritis is the presence of specific autoantibodies, such as intrinsic factor antibodies and parietal cell antibodies. These antibodies interfere with the production of intrinsic factor, a protein necessary for vitamin B12 absorption, which can ultimately lead to pernicious anemia.

Distinguishing Features of Type A Gastritis

Unlike other types of gastritis, Type A gastritis is closely linked to autoimmune disorders. Patients may experience a decrease in gastric acid production due to damage to the acid-secreting cells in the stomach. This type of gastritis is relatively rare compared to Type B gastritis but carries significant health risks if left untreated. Because it can lead to vitamin B12 deficiency and associated complications like neurological issues and fatigue, early diagnosis through endoscopy and blood tests for intrinsic factor and parietal cell antibodies is crucial.

Understanding Type B Gastritis

In contrast, Type B gastritis—also referred to as multifocal atrophic gastritis—is most commonly caused by long-term infection with Helicobacter pylori (H. pylori). This bacterial infection often begins as superficial gastritis and progresses to atrophy over time. Type B gastritis typically affects the antrum of the stomach and results in reduced secretion of gastrin due to damage to G cells. Unlike Type A, Type B gastritis does not involve autoantibodies, and gastric acid levels may remain normal or only slightly reduced.

Shared Characteristics Between Type A and Type B Gastritis

Both Type A and Type B gastritis fall under the category of chronic atrophic gastritis and can result in hypochlorhydria (low stomach acid). However, Type B is far more common than Type A. While Type B gastritis is largely associated with H. pylori infection, Type A is related to immune-mediated destruction of the gastric lining. Due to its association with severe complications such as pernicious anemia, Type A gastritis requires prompt medical attention, including regular monitoring and targeted treatment strategies.

Importance of Early Diagnosis and Treatment

If you suspect you may have Type A gastritis, especially if experiencing symptoms like fatigue, weakness, or unexplained weight loss, it's important to consult a gastroenterologist. Diagnostic procedures such as gastroscopy and laboratory testing for specific antibodies are essential for accurate identification and management of this condition. Timely intervention can help prevent disease progression and reduce the risk of serious complications.