Pernicious Anemia and Vitamin B-12 Deficiency

Medical Author: Melissa Conrad Stöppler, MD
Medical Editor: Charles Davis, MD, PhD

• 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/vitamin B-12 deficiency?
• Can pernicious anemia/ vitamin B-12 deficiency be prevented?
• What is the prognosis for pernicious anemia/ vitamin B-12 deficiency?
• Pernicious Anemia At A Glance
• Patient Discussions: Pernicious Anemia - Symptoms At Onset Of Disease

Featured pernicious anemia patient discussions on symptoms of onset of disease "At age 55, I was recently diagnosed with pernicious anemia. I too, was fatigued, off balance at times walking, sick a lot with flu symptoms, etc. I now give myself vitamin B-12 shots once a week. It was discovered through blood work that I was very low in vitamin B-12. I eat healthier, exercise a couple of times a week and feel somewhat better." "I was diagnosed with pernicious anemia in 1999. I was losing the use of my hands and my muscles. I really was like a mentally challenged person. My tongue was hurting and that is what triggered the diagnosis. When I was first diagnosed, I had to have a B12 shot twice a week and was not allowed outside on my own. I was trained to do the shots on my own, which I still do. At first, I had to have a shot once a month, but soon after, my doctor changed my shots to every two weeks. That’s what I have been on ever since." "I suffered from iron deficiency originally, then I had a split mouth, sore tongue and my hair started to go grey and I was only 30. Went to the Doctors who sent me straight for blood tests and came back that I had pernicious anemia, I had heard of it so from then on I had B12 injections and that was 28 years ago. Since them my mother was diagnosed with it. I also have an underactive thyroid which was diagnosed 8 years ago." Read All Comments on Pernicious Anemia » Top Searched Pernicious Anemia Terms: vitamin B12, reactive hypoglycemia, brown spots, celiac disease, metabolism, iron, bipolar, mental illness, thalassemia, dosing, neurological Patient Discussions are not a substitute for professional medical advice, or treatment. See the disclaimer at the bottom of the comments page.

What is pernicious anemia?

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 to be indicative of anemia. These definitions may vary slightly depending on the source and the laboratory reference used. Pernicious is a term that means destructive, injurious or deadly.

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 is a disease caused by impaired uptake of vitamin B-12 due to the lack of intrinsic factor (IF) in the gastric mucosa. It was termed "pernicious" because before it was learned that vitamin B-12 could treat the anemia, most people that developed the disease died from it.

Anemia can result from disruptions in the production of red blood cells or hemoglobin as well as from an increased destruction of red blood cells or loss of blood.

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. Because of this, the symptoms of pernicious anemia usually do not appear for years. While pernicious anemia is most commonly diagnosed in adults with an average age of 60, a rare, congenital (inborn) type of pernicious anemia has been described.

As with other causes of anemia, symptoms related to decreased oxygen-carrying capacity of the blood can include tiredness and shortness of breath. Vitamin B-12 deficiency also interferes with the function of the nervous system, and symptoms due to nervous system damage may be apparent even before the anemia is discovered.

Pernicious anemia is most common in Caucasian persons of northern European ancestry than in other racial groups. In this population, 10-20 people per 100,000 persons are diagnosed each year with pernicious anemia. Pernicious anemia is also termed Biermer's or Addison's anemia.

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.

Pernicious Anemia - Symptoms At Onset Of Disease

The MedicineNet physician editors ask:

The symptoms of pernicious anemia can vary greatly from patient to patient. What were your symptoms at the onset of your disease?

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