Pernicious anemia is a blood disorder that occurs when the digestive tract fails to absorb enough vitamin B12. The body uses that vitamin to produce oxygen-carrying red blood cells; therefore pernicious anemia results in a decrease in the number of red blood cells. Apart from rare instances of congenital pernicious anemia, the condition usually occurs later in life with the average age of diagnosis being 60, according to Medline Plus, a website of the National Institutes of Health.
Atrophic Gastritis
Atrophic gastritis, a common cause of pernicious anemia, is a condition in which the stomach walls become inflamed. That inflammation destroys cells required to produce essential enzymes and acid used in the digestive process. This affects the ability to absorb vitamin B12 and results in decreased production of normal red blood cells. Those cells begin to divide abnormally and become larger than healthy red blood cells, notes the National Heart Lung and Blood Institute. Removal of part of the stomach or chronic infection with the H. pylori bacteria may cause pernicious anemia, according to the Merck Manuals.
Immune System Activity
A person's immune system may create antibodies that destroy the gastric parietal cells, resulting in reduced production of an important protein. The protein, known as intrinsic factor, plays an essential role in the absorption of vitamin B12. Sometimes the body's immune system attacks the intrinsic factor protein directly, rather than the cells which produce it, notes Medline Plus. In either case, the resulting lack of intrinsic factor results in vitamin B12 deficiency, which in turn causes pernicious anemia.
Diet
In rare instances, people who do not consume an adequate quantity of vitamin B12 may develop pernicious anemia, according to the National Heart Lung and Blood Institute. Vegetarians who avoid all meat and dairy products should take a vitamin B12 supplement to reduce that risk. Others who might not consume enough vitamin B12 include those suffering from alcoholism.
Fatigue Symptoms
The University of Maryland Medical Center notes that fatigue is a typical symptom of pernicious anemia. People with the disorder may suffer from a general sense of tiredness or exhaustion. They might feel light-headed or dizzy when they exert themselves or when they stand up, or they may find themselves becoming short of breath when exercising.
Stomach-related Symptoms
The symptoms of pernicious anemia may include stomach problems such constipation. A person who normally has regular bowel movements may suffer from irregularity and find that they have difficulty passing stools. Some people may experience diarrhea. Some may find that they alternate between diarrhea and constipation, according to the New York University Langone Medical Center. Other symptoms include loss of appetite, changes in the sense of taste and weight loss.
