- Take the Blood Disorders Quiz
- Patient Comments: Pernicious Anemia - Symptoms
- Patient Comments: Pernicious Anemia - Treatments
- Patient Comments: Pernicious Anemia - Share Your Experience
- Patient Comments: Pernicious Anemia - Causes
- Find a local Hematologist in your town
- Pernicious anemia and vitamin B12 deficiency facts
- What is pernicious anemia?
- What is megaloblastic anemia?
- What causes pernicious anemia?
- Is pernicious anemia the same as vitamin B-12 deficiency anemia?
- What are the symptoms of vitamin B-12 deficiency/ pernicious anemia?
- How is pernicious anemia/vitamin B-12 deficiency diagnosed?
- What is the treatment for pernicious anemia and vitamin B-12 deficiency?
- Can pernicious anemia/ vitamin B-12 deficiency be prevented?
- What is the prognosis for pernicious anemia/ vitamin B-12 deficiency?
What is megaloblastic anemia?
Sometimes, anemias are subclassified based upon the size and microscopic appearance of the red blood cells. In this regard, pernicious anemia is a form of megaloblastic anemia. Megaloblastic anemia refers to an abnormally large type of red blood cell (megaloblast). Megaloblasts are produced in the bone marrow when vitamin B-12 or folic acid levels are low. Megaloblastic anemia can also be caused by other disease of the bone marrow and can be a side effect of some cancer chemotherapy drugs.
What causes pernicious anemia?
Pernicious anemia is considered to be an autoimmune disease, in which the body's own immune system mistakenly damages its own tissues. It is believed that the decreased absorption of vitamin B-12 from the gastrointestinal tract in pernicious anemia results from the presence of an autoantibody against intrinsic factor (IF), a protein made in the stomach that is necessary for the absorption of vitamin B-12. Normally, vitamin B-12 binds to intrinsic factor in the stomach, and this facilitates its absorption by the small intestine further along in the digestive process. Along with the autoimmune process that attacks the IF protein and lowers IF levels in stomach secretions, another autoimmune reaction against the stomach lining cells also occurs, resulting in a form of inflammation known as chronic atrophic gastritis.