What Is Pernicious Anemia?
Pernicious anemia (per-NISH-us uh-NEE-me-uh) is a
condition in which the body does not make enough red blood cells due to a lack
of vitamin B12 in the body. It usually occurs in people whose bodies have lost
the ability to absorb vitamin B12 from food.
Pernicious anemia is one of many different types of
anemia. Having anemia means you do
not have enough healthy red blood cells. When a person has anemia, the blood
cannot carry enough oxygen to the cells of the body. The most common symptom of
anemia is feeling tired.
In pernicious anemia, the blood cells do not divide
normally and are too large. They have trouble getting out of the bone marrow.
The problem is due to a lack of vitamin B12 in the body. Vitamin B12 is one of
the B vitamins; B vitamins are found in animal foods such as meat, fish, eggs,
milk, and other dairy products. Vitamin B12 is necessary for the body to make
red blood cells. It is also needed for the normal working of the nervous
People can develop low levels of this important
vitamin in three main ways:
- From the lack of a protein in the stomach that
helps the body absorb vitamin B12. The protein is called intrinsic
(in-TRIN-sik) factor. Intrinsic factor is made by special cells in the lining
of the stomach. In some people, these cells are destroyed by the bodys
immune system or as a result of stomach surgery. When this happens, intrinsic
factor is not produced and vitamin B12 cannot be absorbed. This is the most
common cause of vitamin B12 deficiency.
- From not getting enough vitamin B12 in the diet.
This can be the result of eating a strict vegetarian diet or a poor diet due to
factors such as aging or alcoholism.
- From certain intestinal disorders that interfere
with the absorption of vitamin B12, such as
Crohns disease and intestinal infections.
The condition was named pernicious
anemia because it was often fatal in the years before the cause was discovered
to be a lack of vitamin B12, and no specific treatments were available. Now it
is easy to treat with vitamin B12 pills or injections. Pernicious anemia can be
severe if it goes on for a long time without being treated. If it is not
treated, it can cause permanent damage to the body. Pernicious anemia is
especially common in older adults.
Effects of Pernicious Anemia on the Body
People who have pernicious anemia often feel tired
and weak because the body is not getting enough oxygen. Over time, if
untreated, this disease can cause serious problems for the heart, nerves, and
other parts of the body.
Heart. In people with anemia, the
heart has to work harder to pump blood to get enough oxygen to the bodys
organs and tissues. This stress on the heart can cause
murmurs (an extra or unusual sound heard during the heartbeat), fast or
irregular heartbeats, an enlarged heart, or even
A lack of vitamin B12 or folic acid (folate) can
cause extra problems for the heart because it raises the level in the body of a
chemical called homocysteine (ho-mo-SIS-teen). High levels of homocysteine add
to the buildup of fatty deposits in blood vessels, which in turn can lead to
Nerves. A lack of vitamin B12 can
damage nerve cells and cause problems such as tingling and numbness in hands
and feet and problems with walking and balance. A vitamin B12 deficiency can
cause changes in taste, smell, and vision. Finally, it can cause mental
changes, including memory loss and confusion.
Digestive tract. A lack of vitamin
B12 may change the surface of the tongue and shrink or thin the stomach lining.
Any changes that occur in the stomach can put a person at risk for stomach
Pernicious anemia is usually easy to treat with
vitamin B12 pills or shots, although some people develop permanent nerve damage
before they find out they have the disease and get treatment. Since pernicious
anemia does increase the risk of developing stomach cancer, doctors may do
periodic cancer tests to check for it. Overall, however, people with pernicious
anemia who get proper lifelong treatment can have a normal lifespan.