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Comprehensive evaluation and treatment for all forms of anemia.
Pernicious anemia is a deficiency in red blood cells caused by lack of vitamin B12 in the blood. It is a condition where the body can't make enough healthy red blood cells because it doesn't have enough vitamin B12.
Common signs and symptoms of vitamin B12 deficiency seen in pernicious anemia include:
Anemia is a condition in which the body does not have a sufficient number of red blood cells or hemoglobin. Hemoglobin is present within red blood cells and is important for carrying oxygen to all tissues of the body. In males, anemia is typically defined as hemoglobin level of less than 13.5 gram/100ml, while in women, a hemoglobin level of less than 12.0 gram/100ml is considered indicative of anemia.
Pernicious anemia is a disease where large, immature, nucleated cells (megaloblasts, which are forerunners of red blood cells) circulate in the blood, and do not function as blood cells. It was termed "pernicious" (meaning destructive or deadly) because before it was learned that vitamin B-12 could treat the anemia, most people that developed the disease died from it.
Pernicious anemia is due to an inability to absorb vitamin B-12 (also known as cobalamin or Cbl) from the gastrointestinal tract. Humans get vitamin B-12 from animal products; both meat and dairy products are dietary sources of vitamin B-12. The body is able to store vitamin B-12 for a long time, so inadequate dietary intake must persist for years before a true deficiency of vitamin B-12 is reached. Therefore, the symptoms of pernicious anemia usually do not appear for years.
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 diseases of the bone marrow and can be a side effect of some cancer chemotherapy drugs.
Pernicious anemia is considered 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 results from the presence of an autoantibody against intrinsic factor (IF), a protein made in the stomach necessary for B-12 absorption.
Along with the autoimmune process that attacks the IF protein, another autoimmune reaction against the stomach lining cells also occurs, resulting in a form of inflammation known as chronic atrophic gastritis. Pernicious anemia is sometimes associated with other autoimmune diseases such as Graves' disease, Hashimoto's thyroiditis, and vitiligo.
Pernicious anemia is one specific form of vitamin B-12 deficiency resulting from the autoimmune process. However, other causes of vitamin B-12 deficiency can produce the same signs and symptoms. Other potential causes include:
Vitamin B-12 deficiency affects the nervous system, leading to a variety of symptoms. Sometimes, these may be apparent before symptoms related to the anemia. Neurological symptoms can include:
Anemia symptoms are due to reduced oxygen-carrying capacity:
A deficiency of vitamin B-12 also can alter the surface of the tongue, making it appear shiny or smooth. Sometimes pernicious anemia is diagnosed in a patient with no symptoms, found incidentally via blood tests.
Pernicious anemia may be treated by internal or family medicine specialists as well as specialists in disorders of the blood (hematologists).
The first step is always a thorough history and physical examination. Laboratory tests used to diagnose pernicious anemia include:
Treatment involves replenishing the vitamin B-12 supply. If a condition other than pernicious anemia is responsible, treatment must also address that condition.
Symptoms may improve after just a few days of medical treatment. Life-long treatment is usually required for pernicious anemia.
The autoimmune process that causes pernicious anemia cannot be prevented. However, vitamin B-12 deficiency caused by diet (e.g., in vegetarians or vegans) can be prevented by using oral supplements (100-200 mcg weekly is often sufficient). Pregnant and nursing women who are vegetarians/vegans should take specific care to supplement.
If untreated, neurological complications can be permanent and fatal. However, pernicious anemia is easily and effectively treated with vitamin B-12 administration. With life-long treatment, the prognosis is generally good, though the risk of stomach cancer remains elevated.
Pernicious anemia is a condition in which a person's red blood cell count is low due to a deficiency in vitamin B12. It is caused by impaired uptake of vitamin B12 due to the lack of intrinsic factor (IF) in the gastric mucosa.
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