Severe atrophic gastritis with generalized weakness may be caused by pernicious anemia, malnutrition, viral colds and so on. 1. Pernicious anemia: In severe atrophic gastritis, when the lesion mainly involves the body of the stomach or when antibodies to the mural cells or endofactors are present in the body, the number of mural cells decreases dramatically, and the endofactors secreted by the mural cells also decrease dramatically. The endofactor can bind to vitamin B12 in food, thus protecting it from being digested by the enzymes in the stomach, and then reaching the site of vitamin B12 absorption, the ileum, in order to be absorbed by the body. Vitamin B12 is an important raw material for hematopoiesis. When vitamin B12 is deficient, it can lead to megaloblastic anemia, which is also called pernicious anemia. 2. Malnutrition: severe atrophic gastritis can lead to a series of digestive symptoms, such as nausea, epigastric fullness, poor appetite, etc., when the long-term chronic atrophic gastritis patients eat poorly, malabsorption can lead to patients with malnutrition, which leads to general weakness. 3. Viral colds: patients with severe atrophic gastritis can experience generalized weakness when they have viral infections, such as viral colds. There are other causes of severe atrophic gastritis with generalized weakness, such as myasthenia gravis, etc., which need to be actively consulted to clarify the cause of the disease and then carry out targeted treatment.