Anemia - B12 deficiency

Answer 1

Definition

Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues.

Vitamin B12 deficiency anemia is a low red blood cell count due to a lack of vitamin B12.

See also:

• Megaloblastic anemia
• Pernicious anemia

Alternative Names

Macrocytic anemia

Causes, incidence, and risk factors

Your body needs vitamin B12 to make red blood cells. In order to provide vitamin B12 to your cells:

• You must eat enough foods that contain vitamin B12, such as meat, poultry, shellfish, eggs, and dairy products.
• Your body must absorb enough vitamin B12. Your body uses a special protein, called intrinsic factor, released by cells in the stomach. The combination of vitamin B12 attached to intrinsic factor is absorbed in the last part of the small intestine.

A lack of vitamin B12 in the diet may be due to:

• Eating a vegetarian diet
• Poor diet in infancy
• Poor nutrition during pregnancy

A number of problems can make it difficult for your body to absorb enough vitamin B12:

• ChronicAlcoholism
• Crohn's disease, celiac disease, infection with the fish tapeworm, or other problems that make it difficult for your body to digest foods
• Pernicious anemia, which occurs when your body destroys cells that make intrinsic factor. Intrinsic factor is needed to absorb vitamin B12.
• Surgeries that remove certain parts of your stomach or small intestine, such as some weight-loss surgeries
• Taking antacids and other heartburn medicines for a long period of time

Symptoms

People with mild anemia may have no symptoms, or symptoms may be very mild.

More typical symptoms of vitamin B12 deficiency anemia include:

• Diarrhea or constipation
• Fatigue, lack of energy, or light-headedness when standing up or with exertion
• Loss of appetite
• Pale skin
• Problems concentrating
• Shortness of breath, mostly during exercise
• Swollen, red tongue or bleeding gums

Symptoms from nerve damage caused by vitamin B12 deficiency that has been present for a longer time include:

• Confusion or change in mental status (dementia) in severe cases
• Depression
• Loss of balance
• Numbness and tingling of hands and feet

Signs and tests

A physical exam may show problems with reflexes or a positive Babinskireflex.

The following tests may be done:

• CBC
• Reticulocyte count
• Schilling test(if pernicious anemia is suspected)
• Serum LDH
• Serum vitamin B12 level and serum folate levels

Esophagogastroduodenoscopy(EGD) to examine the stomach, or enteroscopy to examine the small intestine may be done.

Bone marrow biopsy is done only when the diagnosis is not clear.

Treatment

Treatment depends on the cause of B12 deficiency anemia.

• Pernicious anemia requires lifelong vitamin B12 replacement, most often using injections. Some patients can get enough supplementation with high-dose tablets of oral vitamin B12.
• People with anemia due to a lack of dietary vitamin B12 may be told to take vitamin supplements and follow a more balanced diet. Treatment may start with vitamin B12 injections.
• Anemia caused by poor digestion and absorption is treated with vitamin B12 injections until the condition improves. These shots are given every day and then every week at first, and then every month.

Many people may need these shots once a month for the rest of their life. The shots may no longer be needed after Crohn's disease, celiac disease, or alcoholism is properly treated.

Expectations (prognosis)

Treatment for this form of anemia is usually effective.

Any damage to nerves may be permanent, especially if treatment is not started within 6 months of when the symptoms begin.

Complications

Vitamin B12 affects cells that form the outer surface of the body and line inner passageways (epithelial cells). Therefore, a lack of B12 may cause a falsely abnormal Pap smear.

Calling your health care provider

Call your health care provider if you have any of the symptoms of anemia.

Prevention

You can prevent anemia caused by a lack of vitamin B12 by following a well-balanced diet. Vitamin B12 injections can prevent anemia after surgeries known to cause vitamin B12 deficiency. Early diagnosis and prompt treatment can limit the severity and complications of this anemia.

References

Antony AC. Megaloblastic anemias. In: Hoffman R, Benz Ej, Shattil SS, et al., eds. Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone;2008:chap 39.

Kaferle J, Strzoda CE. Evaluation of macrocytosis. Am Fam Physician. 2009;79:203-208.

Answer 2

Definition

Vitamin B12 deficiency anemia is a low red blood cell count due to a lack of vitamin B12. Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to body tissues.

See also:

• Megaloblastic anemia
• Pernicious anemia

Alternative Names

Macrocytic anemia

Causes, incidence, and risk factors

Your body needs vitamin B12 to make red blood cells. In order to provide vitamin B12 to your cells:

• You must eat plenty of foods that contain vitamin B12, such as meat, poultry, shellfish, eggs, and dairy products.
• Your body must absorb enough vitamin B12. A special protein, called intrinsic factor, helps your body do this. This protein is released by cells in the stomach.

A lack of vitamin B12 may be due to dietary factors, including:

• Eating a vegetarian diet
• Poor diet in infants
• Poor nutrition during pregnancy

Certain health conditions can make it difficult for your body to absorb enough vitamin B12. They include:

• Chronicalcoholism
• Crohn's disease, celiac disease, infection with the fish tapeworm, or other problems that make it difficult for your body to digest foods
• Pernicious anemia, a type of vitamin B12 anemia that occurs when your body destroys cells that make intrinsic factor
• Surgeries that remove certain parts of your stomach or small intestine, such as some weight-loss surgeries
• Taking antacids and other heartburn medicines for a long period of time

Symptoms

You may not have symptoms. Symptoms may be mild.

Symptoms can include:

• Diarrhea or constipation
• Fatigue, lack of energy, or light-headedness when standing up or with exertion
• Loss of appetite
• Pale skin
• Problems concentrating
• Shortness of breath, mostly during exercise
• Swollen, red tongue or bleeding gums

If you have low vitamin B12 levels for a long time, you can have nerve damage. Symptoms of nerve damage include:

• Confusion or change in mental status (dementia) in severe cases
• Depression
• Loss of balance
• Numbness and tingling of hands and feet

Signs and tests

The doctor or nurse will perform a physical exam. This may reveal problems with your reflexes.

Tests that may be done include:

• Complete blood count (CBC)
• Reticulocyte count
• LDH level
• Vitamin B12 level

This list may not be all-inclusive.

Other procedures that may be done include:

• Esophagogastroduodenoscopy(EGD) to examine the stomach
• Enteroscopy to examine the small intestine
• Bone marrow biopsy if the diagnosis is not clear

Treatment

Treatment depends on the cause of B12 deficiency anemia. For treatment of anemia due to a lack of intrinsic factor, see: Pernicious anemia

The goal of treatment is to increase your vitamin B12 levels.

• Treatment may include a shot of vitamin B12 once a month. Persons with severely low levels of B12 may need more shots in the beginning. You may need shots every month for the rest of your life.
• 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.

Treatment may no longer be needed after Crohn's disease, celiac disease, or alcoholism is properly treated.

Your doctor or nurse will also recommend eating a well-balanced diet.

Expectations (prognosis)

With treatment, patients usually do well.

Long-term vitamin B12 deficiency can cause nerve damage. This may be permanent if you do not start treatment within 6 months of when your symptoms begin.

Complications

Women with low B12 levels may have a falsely abnormal Pap smear. That is because vitamin B12 affects the way certain cells, called epithelial cells, look.

Calling your health care provider

Call your health care provider if you have any of the symptoms of anemia.

Prevention

You can prevent anemia caused by a lack of vitamin B12 by following a well-balanced diet.

Shots of vitamin B12 can prevent anemia after surgeries known to cause vitamin B12 deficiency.

Early diagnosis and prompt treatment can reduce or prevent complications related to low vitamin B12 levels.

References

Antony AC. Megaloblastic anemias. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 167.

Reviewed By

Review Date: 02/08/2012

Todd Gersten, MD, Hematology/Oncology, Palm Beach Cancer Institute, West Palm Beach, FL. Review provided by VeriMed Healthcare Network. Also reviewed by Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington; David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.