What is Pernicious Anemia?

Mary McMahon
Mary McMahon

Pernicious anemia is a form of megaloblastic anemia which is caused by an inability to absorb vitamin B12 properly. Megaloblastic anemias involve the red blood cells, and in the case of pernicious anemia, the red blood cells are depleted and they may be malformed. Historically, this condition was not identified until people were already experiencing symptoms of anemia, including complications, but today, it can be diagnosed with screening before anemia occurs. People with a family history of pernicious anemia should consider screening to see whether or not they are at risk.

A B12 injection, which can help with pernicious anemia.
A B12 injection, which can help with pernicious anemia.

There are a number of potential causes for pernicious anemia. One is a congenital form, in which a child is born without the ability to absorb vitamin B12. In other cases, an underlying disease process interferes with absorption of this vitamin. In patients with pernicious anemia, the stomach does not produce enough of a substance called intrinsic factor. Without intrinsic factor, the bowels cannot take up vitamin B12, and it is passed as a waste product, rather than being absorbed. Once the body has used up its reserves of vitamin B12 in the production of red blood cells, anemia starts to emerge.

One of the most common symptoms of pernicious anemia is fatigue.
One of the most common symptoms of pernicious anemia is fatigue.

Patients with this condition often have gastrointestinal problems in addition to classic symptoms of anemia such as weakness, lethargy, and pale skin. Pernicious anemia can be diagnosed with a blood test, and with a test in which B12 is injected and a test is done to see how much has been absorbed. Although this condition was once dangerous because it was identified late in many cases, today it is very treatable.

In pernicious anemia, the red blood cells are depleted, and they may be malformed.
In pernicious anemia, the red blood cells are depleted, and they may be malformed.

The treatment for pernicious anemia is B12 supplementation, to make sure that the body has enough of this vitamin. One of the best ways to do this is with periodic B12 injections straight into the muscle. If injections are not an option, a patient may be given B12 pills to take. If the symptoms are not resolved, additional testing can be performed to see if the supplementation doses need to be changed, and to check for other problems which may be causing anemia.

Pernicious anemia involves the inability to absorb B12 properly.
Pernicious anemia involves the inability to absorb B12 properly.

Also known as Addison-Biermer anemia, pernicious anemia tends to be more common in people of Northern European and African descent. Individuals who are at risk include older adults from these genetic backgrounds, people with a family history of the disease, and people with conditions such as diabetes. People who have had bowel resection surgeries or gastric bypasses are also at risk of pernicious anemia, in addition to deficiencies caused by the inability to properly absorb nutrients.

Pernicious anemia is more common in people of African descent.
Pernicious anemia is more common in people of African descent.
An abnormal blood test may cause the doctor to suspect pernicious anemia and pursue further testing.
An abnormal blood test may cause the doctor to suspect pernicious anemia and pursue further testing.
Patients experiencing pernicious anemia may be more likely to develop vitiligo, a condition that reduces the amount of melanin in the skin.
Patients experiencing pernicious anemia may be more likely to develop vitiligo, a condition that reduces the amount of melanin in the skin.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments

Oceana

There are a couple of other pernicious anemia causes besides being unable to produce intrinsic factor. Sometimes, people have too much bad bacteria in their intestines, and this bacteria will eat up all the vitamin B12 before the person can benefit from it. In this case, all you have to do is take antibiotics.

Then, there's the kind that is caused by a poor diet. This can be fixed by either taking B12 supplements or eating more meat and cereals with B12 in them.

JackWhack

I remember watching a documentary about a lady with the symptoms of pernicious anemia. She went to several doctors, and none of them could figure out what was wrong.

She had bad diarrhea for months. She had to miss a lot of work, because she just couldn't leave the toilet long enough to drive there.

She was incredibly weak, and what was so frustrating is that she couldn't get any relief because no one could figure out why this was happening to her. She finally visited a rheumatologist, and he thought to test her for pernicious anemia.

A few injections of B12 started making her feel better. She started taking monthly injections, and she was able to live a normal life.

DylanB

@seag47 – Our bodies can store it up. I have a friend with this type of anemia, and she had to get seven shots during the first week after her pernicious anemia diagnosis.

This was so her body could stock up on it. I guess you can hold onto B12 for awhile, if you have enough of it.

seag47

Why do people undergoing pernicious anemia treatment only need shots once a month? Don't we need a lot more vitamin B12 than that? How do they keep from running out of it?

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