Anemia is a condition in which your blood has a lower than normal number of red blood cells. Anemia also can occur if your red blood cells don’t contain enough hemoglobin. Hemoglobin is an iron-rich protein that gives blood its red color. This protein helps red blood cells carry oxygen from the lungs to the rest of the body.
Your blood contains three types of cells — white blood cells, which fight off infection; platelets, which help blood to clot; and red blood cells, which carry oxygen from your lungs throughout your body. Red blood cells are made in your bone marrow. They contain hemoglobin, an iron-based protein that helps blood cells carry oxygen. With anemia, your body either doesn’t make enough red blood cells or loses them faster than they can be replaced.
There are several types of anemia. The most common type is iron deficiency anemia, caused by a lack of iron in your body. Other types include:
- Vitamin deficiency anemia, megaloblastic anemia — caused by a lack of folic acid and vitamin B12 in your body.
- Anemia of chronic disease — caused when certain chronic diseases (such as cancer, kidney failure, or Crohn’ s disease) interfere with the production of red blood cells.
- Aplastic anemia — caused when bone marrow loses its ability to produce all three types of blood cells. Aplastic anemia is life threatening.
- Hemolytic anemias — caused when red blood cells are destroyed faster than the bone marrow can replace them.
- Sickle cell anemia — caused by a defective type of hemoglobin that makes red blood cells form a crescent or sickle shape. These sickle cells die early, meaning the body is always short of red blood cells. The abnormal shape can block blood flow through small vessels, causing pain. Sickle cell anemia is an inherited condition that affects mainly people of African, Mediterranean, Arabic, or South American descent.
Anemia Causes:
Two common causes of iron deficiency anemia are blood loss (most common) and very rarely decreased absorption of iron from food.
- Blood loss: The source of blood loss may be obvious, such as repeated blood donations, trauma, surgery, or in women who have heavy menstrual bleeding or multiple pregnancies over a short period of time. In other cases, the source of the blood loss is not visible, as in someone who has bleeding in their digestive tract.
- Decreased iron absorption: Normally, the body absorbs iron from food through the gastrointestinal tract. If the GI tract is not functioning correctly, as in people with certain conditions (eg, celiac disease, gastritis), an inadequate amount of iron may be absorbed, leading to iron deficiency anemia. This is a much less common cause of iron deficiency anemia than blood loss.
- Other causes: A common cause of iron deficiency anemia in developing countries is a lack of foods that contain iron. However, this is a rare problem in adults in developed countries such as the United States because many foods have added iron (eg, breakfast cereal, bread, pasta).
- Vegetarians are at increased risk for developing iron deficiency anemia because iron from plant sources is not absorbed as readily as iron from meat sources.
- Pregnant women often develop iron deficiency anemia because of the increased iron requirements of the growing fetus and placenta, and the increased volume of blood circulating in the woman’s body during pregnancy.
Signs And Symptoms of Anemia:
Anemia takes some time to develop. In the beginning, you may not have any signs or they may be mild. But as it gets worse, you may have these symptoms:
- Fatigue
- Weakness
- Dizziness
- Headache
- Numbness or coldness in your hands and feet
- Low body temperature
- Pale skin
- Rapid or irregular heartbeat
- Shortness of breath
- Chest pain
- Irritability
- Not doing well at work or in school
All of these signs and symptoms can occur because your heart has to work harder to pump more oxygen-rich blood through the body.
Diagnosis of Anemia:
- Your doctor will diagnose anemia based on your medical and family histories, a physical exam, and results from tests and procedures.
- Because anemia doesn’t always cause symptoms, your doctor may find out you have it while checking for another condition.
Medical and Family Histories:
- Your doctor may ask whether you have any of the common signs or symptoms of anemia. He or she also may ask whether you’ve had an illness or condition that could cause anemia.
- You also may be asked about the medicines you take, your diet, and whether you have family members who have anemia or a history of it.
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Physical Exam
Your doctor will do a physical exam to find out how severe your anemia is and to check for possible causes. He or she may:
- Listen to your heart for a rapid or irregular heartbeat
- Listen to your lungs for rapid or uneven breathing
- Feel your abdomen to check the size of your liver and spleen
- Your doctor also may do a pelvic or rectal exam to check for common sources of blood loss.
Diagnostic Tests and Procedures:
You may have various blood tests and other tests or procedures to find out what type of anemia you have and how severe it is.
Complete Blood Count:
Often, the first test used to diagnose anemia is a complete blood count (CBC). The CBC measures many parts of your blood.
The test checks your hemoglobin and hematocrit levels. Hemoglobin is the iron-rich protein in red blood cells that carries oxygen to the body. Hematocrit is a measure of how much space red blood cells take up in your blood. A low level of hemoglobin or hematocrit is a sign of anemia.
The normal range of these levels may be lower in certain racial and ethnic populations. Your doctor can explain your test results to you.
The CBC also checks the number of red blood cells, white blood cells, and platelets in your blood. Abnormal results may be a sign of anemia, another blood disorder, an infection, or another condition.
Finally, the CBC looks at mean corpuscular (kor-PUS-kyu-lar) volume (MCV). MCV is a measure of the average size of your red blood cells and a clue as to the cause of your anemia. In iron-deficiency anemia, for example, red blood cells usually are smaller than normal.
Other Tests and Procedures:
If the CBC results show that you have anemia, you may need other tests, such as:
- Hemoglobin electrophoresis (e-lek-tro-FOR-e-sis). This test looks at the different types of hemoglobin in your blood. It can help diagnose the type of anemia you have.
- A reticulocyte (re-TIK-u-lo-site) count. This test measures the number of young red blood cells in your blood. The test shows whether your bone marrow is making red blood cells at the correct rate.
- Tests for the level of iron in your blood and body. These include serum iron and serum ferritin tests. Transferrin level and total iron-binding capacity tests also measure iron levels.
- Because anemia has many causes, you also may be tested for conditions such as kidney failure, lead poisoning (in children), and vitamin deficiencies (lack of vitamins, such as B12 and folic acid).
- If your doctor thinks that you have anemia due to internal bleeding, he or she may suggest several tests to look for the source of the bleeding. A test to check the stool for blood may be done in your doctor’s office or at home. Your doctor can give you a kit to help you get a sample at home. He or she will tell you to bring the sample back to the office or send it to a laboratory.
- If blood is found in the stool, other tests may be used to find the source of the bleeding. One such test is endoscopy (en-DOS-ko-pe). For this test, a tube with a tiny camera is used to view the lining of the digestive tract.
- Your doctor also may want to do bone marrow tests. These tests show whether your bone marrow is healthy and making enough blood cells.
Treatment of Anemia:
Treatment depends on the cause of the anemia and how serious it is. Your doctor may suggest changes in your diet to make sure you receive all of the nutrients you need for healthy blood formation, such as vitamin B12, iron, and folic acid. Your doctor may also suggest nutritional supplements or medication. If your anemia is due to an underlying disease, your doctor will treat that disease.
Drug Therapies:
Erythropoietin plus iron — for anemia of chronic disease. Erythropoietin is a hormone made by the kidneys that stimulates the production of red blood cells.
Corticosteroids (such as prednisone) — for some hemolytic anemias. Corticosteroids suppress the immune system, and may help when anemia is caused by an autoimmune disorder.
Medications that suppress the immune system (such as antithymocyte globulin or ATG and cyclosporine) — for aplastic anemia.
Dietary Changes and Supplements:
Low levels of vitamins or iron in the body can cause some types of anemia. These low levels may be due to poor diet or certain diseases or conditions.
To raise your vitamin or iron level, your doctor may ask you to change your diet or take vitamin or iron supplements. Common vitamin supplements are vitamin B12 and folic acid (folate). Vitamin C sometimes is given to help the body absorb iron.
Iron:
Your body needs iron to make hemoglobin. Your body can more easily absorb iron from meats than from vegetables or other foods. To treat your anemia, your doctor may suggest eating more meat—especially red meat (such as beef or liver), as well as chicken, turkey, pork, fish, and shellfish.
Nonmeat foods that are good sources of iron include:
- Spinach and other dark green leafy vegetables
- Tofu
- Peas; lentils; white, red, and baked beans; soybeans; and chickpeas
- Dried fruits, such as prunes, raisins, and apricots
- Prune juice
- Iron-fortified cereals and breads
You can look at the Nutrition Facts label on packaged foods to find out how much iron the items contain. The amount is given as a percentage of the total amount of iron you need every day.
Iron also is available as a supplement. It’s usually combined with multivitamins and other minerals that help your body absorb iron.
Doctors may recommend iron supplements for premature infants and infants who are fed breast milk only or formula that isn’t fortified with iron.
Large amounts of iron can be harmful, so take iron supplements only as your doctor prescribes.
Vitamin B12:
Low levels of vitamin B12 can lead to pernicious anemia. This type of anemia often is treated with vitamin B12 supplements.
Good food sources of vitamin B12 include:
- Breakfast cereals with added vitamin B12
- Meats such as beef, liver, poultry, and fish
- Eggs and dairy products (such as milk, yogurt, and cheese)
- Foods fortified with vitamin B12, such as soy-based beverages and vegetarian burgers
Folic Acid:
Folic acid (folate) is a form of vitamin B that’s found in foods. Your body needs folic acid to make and maintain new cells. Folic acid also is very important for pregnant women. It helps them avoid anemia and promotes healthy growth of the fetus.
Good sources of folic acid include:
- Bread, pasta, and rice with added folic acid
- Spinach and other dark green leafy vegetables
- Black-eyed peas and dried beans
- Beef liver
- Eggs
- Bananas, oranges, orange juice, and some other fruits and juices
Vitamin C:
- Vitamin C helps the body absorb iron. Good sources of vitamin C are vegetables and fruits, especially citrus fruits. Citrus fruits include oranges, grape fruits, tangerines, and similar fruits. Fresh and frozen fruits, vegetables, and juices usually have more vitamin C than canned ones.
- If you’re taking medicines, ask your doctor or pharmacist whether you can eat grapefruit or drink grapefruit juice. This fruit can affect the strength of a few medicines and how well they work.
- Other fruits rich in vitamin C include kiwi fruit, strawberries, and cantaloupes.
- Vegetables rich in vitamin C include broccoli, peppers, Brussels sprouts, tomatoes, cabbage, potatoes, and leafy green vegetables like turnip greens and spinach.
Severe Procedures:
If your anemia is severe, you may need a medical procedure to treat it. Procedures include blood transfusions and blood and marrow stem cell transplants.
Blood Transfusion:
A blood transfusion is a safe, common procedure in which blood is given to you through an intravenous (IV) line in one of your blood vessels. Transfusions require careful matching of donated blood with the recipient’s blood.
For more information, go to the Blood Transfusion article.
Blood and Marrow Stem Cell Transplant:
A blood and marrow stem cell transplant replaces your faulty stem cells with healthy ones from another person (a donor). Stem cells are found in the bone marrow. They develop into red and white blood cells and platelets.
During the transplant, which is like a blood transfusion, you get donated stem cells through a tube placed in a vein in your chest. Once the stem cells are in your body, they travel to your bone marrow and begin making new blood cells.
For more information, go to the Blood and Marrow Stem Cell Transplant article.
Surgery:
If you have serious or life-threatening bleeding that’s causing anemia, you may need surgery. For example, you may need surgery to control ongoing bleeding due to a stomach ulcer or colon cancer.
If your body is destroying red blood cells at a high rate, you may need to have your spleen removed. The spleen is an organ that removes wornout red blood cells from the body. An enlarged or diseased spleen may remove more red blood cells than normal, causing anemia.