Understanding Pernicious Anemia
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
However, untreated vitamin B-12 deficiency can lead to severe
complications. These can include:
- brain damage
- nerve damage
- heart problems
- chronic anemia
- stomach cancer
What Are the 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
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
- peripheral neuropathy, which is numbness in the
arms and legs
- progressive lesions of the spinal cord
- memory loss
What Causes Pernicious Anemia?
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:
- dairy products
- fortified soy, nut, and rice milk
- nutritional supplements
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
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:
- the long-term use of certain medications and
antibiotics, such as methotrexate
- chronic obstructive pulmonary disease
- chronic alcoholism
- folate (vitamin B-9) deficiency caused by poor diet
or disorders that affect absorption
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
How Is 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.
What Is the Treatment for Pernicious Anemia?
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:
- vitamin B-12 injections that are slowly
decreased over time
- CBC tests to measure vitamin B-12 and iron levels
in blood serum
- blood tests to monitor replacement treatments
The symptoms of long-term damage include:
- an upset stomach
- difficulty swallowing
- weight loss
- iron deficiency
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.