Anemia is a medical condition in which the
blood is low in normal red blood cells. Pernicious anemia is one of the vitamin
B-12 deficiency anemias. It’s caused by an inability to absorb the vitamin B-12
needed for your body to make enough healthy red blood cells. Pernicious anemia
is a rare condition, with a prevalence of .1 percent in the general population and 1.9 percent in people who are older
than 60 years, according to the Journal of Blood
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, though, the disease is relatively easy to treat
with B-12 injections or supplements. However, if left untreated, vitamin B-12
deficiency can lead to severe complications.
What are the symptoms of pernicious anemia?
The progression of pernicious anemia is slow.
It may be difficult to recognize the 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, people
may have neurological symptoms. These can include:
- an unsteady gait
- spasticity, which is stiffness and tightness in the
neuropathy, which is numbness in the arms and legs
- progressive lesions of the spinal cord
- memory loss
Other symptoms of a B-12 deficiency, which
can overlap with pernicious anemia, include:
What causes pernicious anemia?
Lack of vitamin B-12
People with anemia have low levels of normal
red blood cells (RBCs). Vitamin B-12 plays a role in creating RBCs, so the body
requires an adequate intake of vitamin B-12. Vitamin B-12 is found in:
- dairy products
- fortified soy, nut, and rice milks
- nutritional supplements
Lack of IF
Your body also needs a type of protein called
intrinsic factor (IF) to absorb vitamin B-12. 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
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 can’t absorb vitamin B-12.
Without enough vitamin B-12, the body will
produce abnormally large red blood cells 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 decreases the amount
of oxygen-carrying red blood cells in the bloodstream and can lead to fatigue
Pernicious anemia is a type of 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:
- long-term use of certain medications and antibiotics,
such as methotrexate and azathioprine
- chronic obstructive pulmonary disease (COPD)
- chronic alcoholism
- folate (vitamin B-9) deficiency caused by poor diet or conditions
that affect absorption
B-12 deficiency vs. pernicious anemia
Other vitamin B-12 deficiencies, such as those
caused by poor diet, are often confused with pernicious anemia. Pernicious
anemia is strictly an autoimmune disorder. It results from a lack of IF and
poor B-12 absorption. This vitamin deficiency can be treated by altering your
diet or adding a B-12 supplement or B-12 injection to your healthcare regimen.
In people with B-12 deficiencies or regular
anemia, the body can absorb B-12. On the other hand, someone with pernicious
anemia struggles to do so. Pernicious anemia is also seen in children who are
born with a genetic defect that prevents them from making IF.
Risk factors for pernicious anemia
Some individuals are more
likely than others to develop pernicious anemia. Risk factors include:
- having a family history of the disease
- being of Northern European or Scandinavian descent
- having type 1 diabetes, an autoimmune condition, or
certain intestinal diseases such as Crohn’s disease
- having had part of your stomach or intestines removed
- being 60 years or older
- being strictly vegetarian and not taking a B-12
Your risk of developing
pernicious anemia also increases as you get older.
Diagnosing pernicious anemia
Your doctor will usually need to do several
tests to diagnose you with pernicious anemia. These include:
Complete blood count:
This test measures vitamin B-12 and iron levels in blood serum.
Vitamin B-12 deficiency test: Your doctor can assess your vitamin B-12 levels through
a blood test. Low levels indicate a deficiency.
doctor may also want to see if there has been any damage to your stomach walls.
They can diagnose this through a biopsy. The biopsy involves removing a sample
of the stomach’s cells. The cells are then examined microscopically for any
IF deficiency test: 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 diseased and healthy tissue. In this
case, the antibodies destroy the cells making IF.
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.
Treatment begins with:
- vitamin B-12 injections that are slowly decreased over
- complete blood counts to measure vitamin B-12 and iron
levels in blood serum
- blood tests to monitor replacement treatments
Vitamin B-12 injections can be given daily or
weekly until the B-12 levels return to normal (or close to normal). During the
first few weeks of treatment, your doctor may recommend limiting physical
activity. After your vitamin B-12 levels are normal, you’ll only need to get
the shot once per month. You can administer the shots yourself or have someone
else give them to you at home to save you trips to the doctor.
After your B-12 levels are normal, your
doctor may recommend you take regular doses of B-12 supplements instead of the
injection. These come in pills, nasal gels, and sprays.
Your doctor may want to monitor
you on a long-term basis. This will help them identify possible serious effects
of pernicious anemia. The most dangerous complication is gastric cancer. They can check for the start of cancer at regular
visits and through biopsies.
Other potential complications of pernicious
- nerve damage
- digestive tract problems
- memory problems, confusion, or other neurological
- heart damage
These complications most often stem from
long-lasting pernicious anemia. They can be permanent.
Many people with pernicious anemia require
lifelong treatment and monitoring. This can help prevent long-term damage. The
symptoms of long-term damage include:
- an upset stomach
- difficulty swallowing
- weight loss
- iron deficiency
Talk to your doctor if you think you may have
symptoms of pernicious anemia. Early diagnosis, treatment, and close monitoring
are important for preventing any future problems.