Pernicious anemia is an autoimmune disorder in which your body can’t make enough healthy red blood cells because it can’t absorb enough vitamin B-12. It’s sometimes called vitamin B-12 deficiency anemia. Anemia is a medical condition in which the blood is low in normal red blood cells.
This type of anemia is called “pernicious” because it was once considered a deadly disease. This was due to the lack of available treatment. Today, the disease is relatively easy to treat with B-12 injections or supplements.
However, untreated vitamin B-12 deficiency can lead to severe complications. These can include:
The progression of pernicious anemia is very slow, making it difficult to recognize symptoms because you may have become used to not feeling well.
Commonly overlooked symptoms include:
In rare cases of pernicious anemia, you may have neurological symptoms. These can include:
Anemia is a medical condition in which the blood is low in normal red blood cells. In the case of pernicious anemia, the body requires both vitamin B-12 and a type of protein called intrinsic factor (IF) to make red blood cells. Vitamin B-12 is found in:
IF is a protein produced by cells in the stomach. After you consume vitamin B-12, it travels to your stomach where it binds with IF. The two are then absorbed in the last part of your small intestine.
In most cases of pernicious anemia, the body’s immune system attacks and destroys the cells that produce IF in the stomach. If these cells are destroyed, the body can’t make IF and it can’t absorb vitamin B-12.
Without enough vitamin B-12, the body will produce abnormally large red blood cells, which are called macrocytes. Because of their large size, these abnormal cells may not be able to leave the bone marrow, where red blood cells are made, and enter the bloodstream. This results in a decrease in oxygen-carrying red blood cells in the bloodstream. This can lead to fatigue and weakness.
Pernicious anemia is a type of large cell, or macrocytic, anemia. It’s sometimes called megaloblastic anemia because of the abnormally large size of the red blood cells produced.
Pernicious anemia is not the only kind of macrocytic anemia. Other causes of abnormally large red blood cells include:
Other causes of vitamin B-12 deficiency, such as poor diet, are often confused with pernicious anemia. Pernicious anemia is strictly an autoimmune disorder resulting from a lack of IF. Pernicious anemia is also seen in children who are born with a genetic defect that prevents them from making IF.
Your doctor will usually need to do several tests to diagnose you with pernicious anemia. These include:
Vitamin B-12 levels are assessed through a blood test. Low levels indicate a deficiency.
Your doctor may also want to see if there has been any damage to your stomach walls. This can be easily diagnosed through a biopsy. A biopsy removes a sample of the stomach’s cells. The cells are then examined microscopically for any damage.
Intrinsic factor deficiency is tested through a blood sample. The blood is tested for antibodies against IF and the stomach’s cells.
In a healthy immune system, antibodies are responsible for finding bacteria or viruses. They then mark the invading germs for destruction. In an autoimmune disease, such as pernicious anemia, the body’s antibodies stop distinguishing between disease and healthy tissue. In this case, they destroy the cells making IF.
The treatment for pernicious anemia is a two-part process. Your doctor will treat any existing vitamin B-12 deficiency and check for iron deficiency. You’ll have lifelong monitoring to look for long-term consequences.
Treatment begins with:
The symptoms of long-term damage include:
Your doctor may want to continue monitoring you on a long-term basis. This will focus on identifying any possible serious consequences of pernicious anemia. The most dangerous complication is gastric cancer. They can check for the start of cancer at regular visits and through biopsies.
Talk to your doctor if you think you may have the symptoms of pernicious anemia. Early diagnosis and treatment are important for preventing any future complications.