Vitamin B12 deficiency anemia | |
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Synonyms | Pernicious anemia, Biermer's anemia, Addison's anemia, Addison–Biermer anemia |
Normal red blood cells | |
Classification and external resources | |
Specialty | Hematology |
ICD-10 | D51.0 |
ICD-9-CM | 281.0 |
DiseasesDB | 9870 |
MedlinePlus | 000569 |
eMedicine | med/1799 |
MeSH | D000752 |
Vitamin B12 deficiency anemia, of which pernicious anemia is a type, is a disease in which not enough red blood cells are present due to a lack of vitamin B12. The most common initial symptom is feeling tired. Other symptoms may include shortness of breath, pale skin, chest pain, numbness in the hands and feet, poor balance, a smooth, red tongue, poor reflexes, and confusion. If treatment is not provided, some of these problems may become permanent.
Although pernicious anemia technically refers to cases resulting from not enough intrinsic factor, it is often used to describe all cases of anemia due to not enough vitamin B12. Lack of intrinsic factor is most commonly due to an autoimmune attack on the cells that make it in the stomach. It can also occur following the surgical removal of part of the stomach or from an inherited disorder. Other causes of low vitamin B12 include a poor diet, celiac disease, and a tapeworm infection. When suspected, diagnosis is made by blood and, occasionally, bone marrow tests. Blood tests may show fewer but larger red blood cells, low numbers of young red blood cells, low levels of vitamin B12, and antibodies to intrinsic factor.
Pernicious anemia due to lack of intrinsic factor is not preventable. Vitamin B12 deficiency due to other causes may be prevented with a balanced diet or with supplements. Pernicious anemia can be easily treated with either injections or pills of vitamin B12. If the symptoms are severe, injections are typically recommended initially. For those who have trouble swallowing pills, a nasal spray is available. Often, treatment is lifelong.
Pernicious anemia due to autoimmune problems occurs in about one per 1000 people. Among those over the age of 60, about 2% have the condition. It more commonly affects people of northern European descent. Women are more commonly affected than men. With proper treatment, most people live normal lives. Due to a higher risk of stomach cancer, those with pernicious anemia should be checked regularly for this. The first clear description was by Thomas Addison in 1849. The term "pernicious" means "deadly", and was used as before the availability of treatment the disease was often fatal.