Pernicious anemia
Pernicious anemia is a disease where not enough red blood cells are produced due to a deficiency of vitamin B12. Those affected often have a gradual onset. The most common initial symptoms are feeling tired and weak. Other symptoms may include shortness of breath, feeling faint, a smooth red tongue, pale skin, chest pain, nausea and vomiting, loss of appetite, heartburn, numbness in the hands and feet, difficulty walking, memory loss, muscle weakness, poor reflexes, blurred vision, clumsiness, depression, and confusion. Without treatment, some of these problems may become permanent.
| Pernicious anemia | |
|---|---|
| Other names | Vitamin B12 deficiency anemia, Biermer's anemia, Addison's anemia, Addison–Biermer anemia |
| Micrograph showing nodular enterochromaffin-like cell hyperplasia, as demonstrated with chromogranin A immunostaining, in the body of the stomach. Parietal cells are not readily apparent. These changes are in keeping with autoimmune metaplastic atrophic gastritis, a histologic correlate of vitamin B12 deficiency anemia. | |
| Specialty | Hematology |
| Symptoms | Feeling tired, shortness of breath, pale skin, numbness in the hands and feet, confusion, poor reflexes |
| Usual onset | Any age, particularly those over 60 years old |
| Causes | Not enough intrinsic factor |
| Diagnostic method | Blood tests, bone marrow tests |
| Treatment | Vitamin B12 injections |
| Prognosis | With treatment a normal life |
| Frequency | 1 per 1000 people |
Pernicious anemia refers to a type of vitamin B12 deficiency anemia that results from lack of intrinsic factor. Lack of intrinsic factor is most commonly due to an autoimmune attack on the cells that create it in the stomach. It can also occur following the surgical removal of all or part of the stomach or small intestine; from an inherited disorder or illnesses that damage the stomach lining. When suspected, diagnosis is made by blood tests initially a complete blood count, 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. Diagnosis is not always straightforward and can be challenging.
Because pernicious anemia is due to a lack of intrinsic factor, it is not preventable. Pernicious anemia can be treated with injections or pills of vitamin B12. If the symptoms are serious, injections are typically recommended initially. For those who have trouble swallowing pills, a nasal spray is available. Often, treatment may be needed for life.
Pernicious anemia due to autoimmune problems occurs in about one per 1000 people in the US. 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 this term came into use because, before the availability of treatment, the disease was often fatal.