Pernicious anemia is an autoimmune condition that leads to a lack of red blood cells. A deficiency in vitamin B-12 causes it.
This article explains the symptoms of pernicious anemia, and how it differs from other types of anemia. It also discusses available treatments.
Pernicious anemia is a rare condition that 0.1 percent of people are thought to be affected by, with a higher occurrence among those over 60 years of age.
A person with pernicious anemia may experience:
Pernicious anemia is a type of anemia, which is when a person is unable to make enough red blood cells. Pernicious anemia is the result of a problem with the immune system.
When a person has pernicious anemia, their gut does not absorb vitamin B-12 properly. This causes a vitamin B-12 deficiency. Up to 50 percent of adults with a vitamin B-12 deficiency may have pernicious anemia.
People find vitamin B-12 in the following foods:
- dairy products
The body needs vitamin B-12 to produce red blood cells. Being deficient in vitamin B-12 means the body is unable to make enough red blood cells.
Red blood cells help carry oxygen around the body, and the body needs oxygen to function properly.
A lack of red blood cells means the body’s tissues do not get enough oxygen. This shortage is what causes the symptoms of pernicious anemia.
Pernicious anemia is one type of vitamin B-12 anemia. It is a condition caused by a problem with the immune system.
There are a number of other types of vitamin B-12 deficiency anemia, which have different causes.
Causes of vitamin B-12 deficiency anemia may include:
- poor diet
- gastrectomy, where surgery removes part or all of the stomach
- celiac disease
- Crohn’s disease
- gastrointestinal tract infection
- long-term use of anti-acid medication
Vitamin B-12 deficiency anemia, including pernicious anemia, is a type of megaloblastic anemia.
This name comes from the type of red blood cells or megaloblasts produced when a person is vitamin-B12 deficient. Megaloblasts are an abnormally large type of red blood cell.
Doctors think pernicious anemia is due to a problem with the immune system.
A protein called intrinsic factor helps a person absorb vitamin B-12 in the gut. The stomach makes intrinsic factor. However, people with pernicious anemia release an antibody in error. This antibody attacks the cells in the stomach that make intrinsic factor. This autoimmune reaction may reduce or stop its production.
A lack of intrinsic factor means the gut cannot absorb vitamin B-12 from food. The body cannot make enough red blood cells without having sufficient vitamin B-12.
A doctor will ask a person about their symptoms to diagnose pernicious anemia.
They may also ask about:
- any stomach surgeries
- any digestive disorders
- their diet
- family history of autoimmune conditions
- family history of anemia
The doctor may also examine the person. They may also carry out tests to reach a diagnosis. These can include the following blood tests:
- Complete blood count: This checks hemoglobin levels.
- Reticulocyte count: This measures levels of young red blood cells.
- Intrinsic factor antibodies: This records levels of intrinsic factor antibodies.
The doctor may also carry out a bone marrow test. The two types of bone marrow test are an aspiration or a biopsy. In both types, the doctor looks for enlarged bone marrow cells, which are a sign of pernicious anemia.
Doctors treat pernicious anemia with vitamin B-12 replacement therapy, which they give via vitamin B-12 shots.
A doctor will inject a vitamin B-12 shot into a person’s muscles. Injections are given on a daily or weekly basis until vitamin B-12 levels return to normal.
Vitamin B-12 oral pills are a less frequently used treatment. A 2016 review, however, found them to be an effective alternative to vitamin B-12 shots. It also noted that people might prefer taking pills.
It is best for people to discuss the various options with their doctor who can recommend the most appropriate treatment for each person.
Symptoms may start to improve a few days or weeks after treatment begins.
Pernicious anemia puts additional stress on a person’s heart. This is because it has to work harder to pump oxygenated blood around the body.
The additional stress on the heart may cause:
With the right treatment, the symptoms of pernicious anemia can be well-managed.
As pernicious anemia is an autoimmune condition, people may need life-long treatment to control symptoms.
Doctors can treat the vitamin B-12 deficiency. However, there is not yet a cure for the immune system reaction that causes this deficiency to occur.