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What is Pernicious Anemia?
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues. There are many types of anemia.
Pernicious anemia is a decrease in red blood cells that occurs when the intestines cannot properly absorb vitamin B12.
What Causes Pernicious Anemia?
Pernicious anemia is considered to be an autoimmune disease, in which the body’s own immune system mistakenly damages its own tissues. It is believed that the decreased absorption of vitamin B-12 from the gastrointestinal tract in pernicious anemia results from the presence of an autoantibody against intrinsic factor (IF), a protein made in the stomach that is necessary for the absorption of vitamin B-12. Normally, vitamin B-12 binds to intrinsic factor in the stomach, and this facilitates its absorption by the small intestine further along in the digestive process. Along with the autoimmune process that attacks the IF protein and lowers IF levels in stomach secretions, another autoimmune reaction against the stomach lining cells also occurs, resulting in a form of inflammation known as chronic atrophic gastritis.
Symptoms of Pernicious Anemia
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:
- chest pain
- weight loss
In rare cases of pernicious anemia, you may have neurological symptoms. These can include:
- an unsteady gait
- spasticity, which is stiffness and tightness in the muscles
- peripheral neuropathy, which is numbness in the arms and legs
- progressive lesions of the spinal cord
- memory loss
How Pernicious Anemia Diagnosed?
Your doctor will usually need to do several tests to diagnose you with pernicious anemia. These include:
- a complete blood count (CBC) test
- a vitamin B-12 deficiency test
- an IF deficiency test
- a biopsy to look for cell damage in the stomach
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.
Treatment for Pernicious Anemia
The goal of treatment is to increase your vitamin B12 levels:
- Treatment involves a shot of vitamin B12 once a month. Persons with severely low levels of B12 may need more shots in the beginning.
- Some patients may also need to take vitamin B12 supplements by mouth. For some people, high-dose vitamin B12 tablets taken by mouth work well, and shots are not needed.
- A certain type of vitamin B12 may be given through the nose.
Your doctor or nurse will also recommend eating a well-balanced diet.
Possible Complications of Pernicious Anemia
People with pernicious anemia may have gastric polyps. They are also more likely to develop gastric cancer and gastric carcinoid tumors.
Brain and nervous system problems may continue or be permanent if treatment is delayed.
A woman with low B12 levels may have a false positive Pap smear. This is because vitamin B12 deficiency affects the way certain cells (epithelial cells) in the cervix look.