Pernicious anemia, also known as Addison's anemia, is a type of megaloblastic anemia caused by a deficiency of vitamin B12 (or cobalamin) in the body, leading to symptoms such as weakness, pallor, tiredness and tingling of the hands and feet, for example. Learn more about vitamin B12.
This type of anemia is usually discovered after 30 years of age, however in cases of child malnutrition, for example, there may be a deficiency of this vitamin, characterizing juvenile pernicious anemia.
The diagnosis of pernicious anemia is made mainly through laboratory tests, in which the concentration of vitamin B12 in the urine is checked, for example. Treatment is usually done by supplementing vitamin B12 and folic acid, in addition to adopting a healthy diet rich in vitamin B12.
Main symptoms
The symptoms of pernicious anemia are related to the lack of vitamin B12 in the body, the main ones being:
- Weakness; Paleness; Headache; Tiredness; Diarrhea; Smooth tongue; Tingling in the hands and feet; Heart palpitations; Dizziness; Shortness of breath; Irritability; Cold feet and hands; Appearance of sores in the corner of the mouth.
In the most severe cases of pernicious anemia it is possible to have impairment of the nervous system, which can lead to difficulties in walking, depression and mental confusion. Learn more about the symptoms of pernicious anemia.
Possible causes
Pernicious anemia is characterized by a lack of vitamin B12 in the body by impaired absorption of this vitamin due to deficiency of intrinsic factor, which is a protein to which vitamin B12 binds to be absorbed by the body. Thus, in deficiency of intrinsic factor the absorption of vitamin B12 is compromised.
The most likely cause of pernicious anemia is immunological: the immune system is likely to act improperly on the gastric mucosa, causing its atrophy and chronic inflammation, which results in increased hydrochloric acid secretion from the stomach and decreased intrinsic factor production, thus decreasing the absorption of vitamin B12.
In addition to the immunological cause, pernicious anemia can be caused by situations such as celiac disease, homocystinuria, cobalt deficiency, child malnutrition, treatment with paraminosalicylic acid and malnutrition during pregnancy, which can cause the baby to be born with pernicious anemia.
How the diagnosis is made
The diagnosis of pernicious anemia is made according to the person's symptoms and eating habits. However, to confirm the diagnosis it is necessary to perform other tests such as digestive endoscopy, which aims to identify lesions in the stomach. Understand how endoscopy is done.
The laboratory test used to confirm the diagnosis of pernicious anemia is the Schilling test, in which radioactive vitamin B12 is administered orally and 2 hours later an injection containing non-radioactive vitamin B12 is administered. After 24 hours, urine is collected and analyzed in the laboratory. If a low concentration of radioactive vitamin B12 is found in the urine, intrinsic factor associated with vitamin B12 is administered three to seven days after the first test. After 24 hours the urine is collected and analyzed again and if there is a correction of the concentration of vitamin B12 in the urine, the test is said to be positive for pernicious anemia, since the body has been provided with a protein that is not being produced and that solves the problem.
In addition to the Schilling test, a complete blood count may be requested, as it is also an examination that allows the diagnosis of anemia. The blood count for pernicious anemia consists of high values of CMV (Average Corpuscular Volume), since the red blood cells are larger, a decrease in the total number of red blood cells, an increase in the RDW, which indicates that there is great variation between the size of the red blood cells, and presence of changes in the shape of red blood cells.
A myelogram may also be requested, which is the test that indicates how the bone marrow is working, which in the case of pernicious anemia reveals the presence of large and immature erythroid precursors. This test, however, is invasive and is rarely requested to help diagnose anemia. See which tests confirm anemia.
How to treat
The treatment of pernicious anemia can be done with injections of vitamin B12 containing 50 - 1000µg or oral tablet containing 1000µg of vitamin according to the medical recommendation. In addition, the use of folic acid may be recommended to prevent neuronal consequences. Learn more about the treatment of pernicious anemia.
It is also important to consult a nutritionist so that you can have better guidance on the foods that should be consumed in pernicious anemia, with the consumption of red meats, eggs and cheese, for example, being normally indicated. See which foods are rich in vitamin B12.
Watch the following video and learn more about this type of anemia:
