Symptoms Causes and Cures

Anemia is a condition that occurs when there are too few properly functioning red bloods cells to carry enough oxygen to the body. Anemia may have different underlying causes. Treatment of anemia depends on its cause and may involve dietary changes, medication, and blood transfusions.

KEYWORDS

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Erythrocytes

Hematology

Hemoglobin

Hemolysis

Carrie's Story

When Carrie turned thirteen, she was determined to finally lose all of what she called her "baby fat." She longed to look like the skinny models who graced the covers of the fashion magazines. Carrie stopped eating the well-balanced meals her mother made. Instead, she grabbed rice cakes or low-fat chips to stop the hunger pangs. At about the same time, Carrie got her period for the first time.

It was not long before Carrie started to feel lightheaded whenever she stood up, and in gym class she had to stop and rest every five minutes. Her gym teacher noticed Carrie's behavior and how pale she looked and suspected that Carrie had iron deficiency anemia. This type of ane-mia is very common in teenage girls because of poor eating habits and iron loss due to menstruation. ^* At the coach's suggestion, Carrie visited her doctor. Together Carrie and her doctor came up with a healthy diet and exercise plan to help Carrie reach an appropriate weight and keep her iron level normal.

What Is Anemia?

Anemia (a-NEE-me-a) is not a disease in itself. Instead, it is a sign that the body has a problem with its red blood cells. The blood of a person with anemia does not contain enough red blood cells or enough of the protein hemoglobin (he-mo-GLOW-bin). Anemia can develop because of poor nutrition, excessive blood loss, destruction of red blood cells, abnormal hemoglobin, or from a number of other causes. But no matter what causes anemia, the result is always the same: the blood does not carry enough oxygen to the cells throughout the body, so the body cannot function normally.

^* menstruation (men-stroo-A-shun) is the discharge of bood and tissue through the vagina that occurs periodically to women of child-bearing age. Because it usually occurs at about four-week intervals, it is often called the "monthly period."

How Is Blood Made in a Healthy Person?

Blood consists of red blood cells, white blood cells, platelets, and plasma. Red blood cells, or erythrocytes (e-RITH-ro-sites), are the most numerous cells in the blood and give blood its red color. The tissues and cells in the body require oxygen to function properly, and erythrocytes are specialized to carry and distribute oxygen because they contain hemoglobin. Hemoglobin has the unique property of being able to absorb oxygen in the lungs, where it is plentiful, and release oxygen to the cells of the body, where it is needed. Hemoglobin consists of four protein molecules, called globins, and up to four heme molecules. The heme molecules are red-pigmented, nonprotein, iron-binding compounds, and they are responsible for binding to and transporting oxygen and carbon dioxide.

In a healthy person, erythrocytes are produced by a process called hematopoiesis (he-ma-tow-po-EE-sis). Hematopoiesis takes place in the bone marrow, which is the tissue that fills the center of most bones. All blood cells originate from one type of cell in the marrow called a stem cell. As red blood cells are produced from stem cells and mature in the marrow, they begin to fill with hemoglobin. A healthy red blood cell contains about 300 hemoglobin molecules, and these take up most of its volume.

When erythrocytes mature, they also get rid of most of the normal components of cells (such as DNA, the nucleus, the endoplasmic reticulum, and the mitochondria). Without these components, erythrocytes cannot grow and divide, so they have a short life. Each cell survives for only about 120 days. The spleen, which is an oval organ located between the stomach and the diaphragm on the left side of the body, contains cells called macrophages (MAK-ro-fayj-ez). The macrophages engulf and break down the old, dying erythrocytes and recycle the iron from the hemoglobin molecules so that it can be used to make more hemoglobin. Every second, about 2 million erythrocytes die, and they must be replaced by hematopoiesis at exactly the same rate.

Granny Heath
and Liver Therapy

Before and during the early twentieth century, the ingestion of great amounts of liver served as an effective means for preventing and treating most types of anemia.

In My Second Life (1944), author and physician Thomas Hall Shastid recalls his school teacher "Granny Heath," who advocated that, cooked or raw, the liver of just about any farm animal was the perfect remedy for what she called the "littleness of blood."

Medical history records that Dr. George R. Minot (1885-1950), Dr. William Parry Murphy (b. 1892), and Dr. George Hoyt Whipple (1878-1976) were the actual creators of the first effective treatment for pernicious anemia using liver. They were awarded the Nobel Prize in 1934 for their research on blood chemistry and histology, which established the scientific basis for successful use of liver therapy.

The U.S. and the World

If the body detects a shortage of red blood cells, the kidneys make a hormone called erythropoietin (ee-rith-ro-po-EE-tin). This protein is secreted into the blood, which then signals the bone marrow to make more red blood cells.

What Is Different in a Person with Anemia?

Blood production is a complex process that requires communication between many parts of the body, including the bone marrow, the kidneys, and the spleen. There are many places in the process where something can go wrong. Problems with stem cells, replication and maturation of erythrocytes, the manufacture of hemoglobin, improper signaling between the kidney and bone marrow (erythropoietin), and problems with spleen function (destruction of cells by macrophages) can result in anemia. A person can have anemia because of an inherited blood disorder, because of a blood condition he or she acquired somehow, and even because of diseases not directly related to the blood.

There are several dozen types of anemia that are categorized by their underlying cause. When doctors test blood for anemia, they often describe the blood by the hemoglobin content of red blood cells (color) and by the size and shape of red blood cells. These descriptions can point a doctor toward the underlying disorder. Treatment is specific for each type of anemia and is based on treating the underlying disease.

What Are the Different Types of Anemia?

There are three broad categories of causes of anemia. First, when someone is injured and loses a great deal of blood, anemia can develop because the body's total blood volume is lost faster than it can be replaced. In the second category, the process of making red blood cells in the body is not working normally: bone marrow does not make enough erythrocytes, the erythrocytes do not contain enough hemoglobin, or the hemoglobin does not function correctly. In the third category, red blood cells are destroyed faster than the marrow can replenish them. Some of the most common types of anemia in each category are described below.

First Category: Anemia from Blood Loss

People who lose a lot of blood very quickly, like those who have been injured in an accident, had a blood vessel burst, or have lost blood during surgery, can become anemic because the body cannot make blood as fast as it is being lost. In cases where blood loss is life threatening, a person can have the lost blood replaced through a blood transfusion ^* . In less severe cases, the body will slowly bring the blood volume and hemoglobin content back to normal by itself. In fact, a person can lose two-thirds of his or her blood volume over a 24-hour period without dying. Other people have a place in their body that is constantly bleeding a little bit, such as a wound in the skin or mucous membranes inside the body (ulcer). In these cases, the source of bleeding needs to be found and treated, and dietary supplements of iron often are needed to help boost hemoglobin production.

^* blood transfusion is the process of giving blood (or certain cells or chemicals found in the blood) to a person who needs it.

Second Category: Decreased Production of Red
Blood Cells

Anemias caused by a decreased production of red blood cells are also called hypoplastic anemias, and many different conditions and disorders can cause this kind of anemia.

Nutritional causes

Certain important vitamins and minerals, such as iron, vitamin B12, and folic acid, are necessary for the bone marrow to make hemoglobin and erythrocytes. If these elements are missing from the diet or are not absorbed from the diet, anemia can develop. Adding food rich in these elements or adding supplements to the diet helps replenish the blood supply.

Iron deficiency anemia occurs when a person does not eat enough foods containing iron or when the body has problems absorbing iron. A low iron level in the body means that there is not enough iron available to make hemoglobin, which results in decreased production of red blood cells. This is a very common type of anemia, especially in infants and teenagers, who need lots of iron to fuel growing bodies. Also, 30-50% of American women are at risk for anemia because of blood loss during menstruation and inadequate amounts of iron in their diets to offset these monthly losses. Iron deficiency anemia is characterized by small red blood cells.

Pernicious anemia occurs when a person does not eat enough foods containing vitamin B12 or is unable to absorb B12 properly. To absorb vitamin B12, the lining of the stomach must produce hydrochloric acid and make a chemical that scientists call "intrinsic factor." If acid production is decreased or intrinsic factor is missing, the vitamin cannot be absorbed. This type of anemia usually affects adults between the ages of 50 and 60, but it is rare in African American and Asian people. People with a poor diet, bulimia, anorexia nervosa, diabetes, or thyroid disease, or who have had stomach surgery, stomach cancer, or a family history of pernicious anemia are prone to this problem. It usually develops gradually, so the symptoms are hard to detect.

Genetic causes

Sometimes people are born with diseases that diminish the body's ability to produce red blood cells. Thalassemia (thal-a-SEE-me-a) and sideroblastic (sid-er-o-BLAS-tik) anemia both occur because the bone marrow cannot produce hemoglobin normally.

Thalassemia is an inherited disorder in which the rate of hemoglobin production is too low. In this condition, the globin portion of hemoglobin is defective. This disorder is most common in people of Mediterranean, African, and Asian ancestry. Thalassemia is divided into two categories: major and minor. People born with thalassemia major have severe anemia during the first year of life that results in slow growth, abnormal bone development, and an enlarged liver and spleen. People with thalassemia minor often do not have any symptoms.

In sideroblastic anemia, the heme molecule of hemoglobin is not made correctly. This problem can be a genetic disorder, but it also can occur in people suffering from alcoholism, people exposed to toxins such as lead, or people who have acquired bone marrow disorders.

Aplastic anemia and bone marrow disorders

Aplastic anemia describes a category of anemias in which the hematopoietic (blood-forming) cells of the bone marrow are destroyed. In many cases, doctors do not know why these cells have been destroyed. In other cases, the blood-forming cells are destroyed by cancer of the bone marrow or by exposure to toxic chemicals, radiation, certain antibiotics, or other medications. A bone marrow transplant from an identical twin or from a relative with compatible cell types can be used to treat aplastic anemia, but it is often difficult to find a donor with the right cell type. Finding treatment for aplastic anemia is an active field of research.

Infection and other disorders

People who frequently are ill with infections are prone to anemia because the infection causes the production of red blood cells to slow down. Anemia is very common in people with AIDS because their immune systems ^* do not function normally and they are prone to infections. People who have diseases of their kidneys often develop anemia because the kidneys no longer respond to decreases in red blood cells by producing enough erythropoietin.

Third Category: Hemolytic Anemias

Hemolytic anemias are caused by the premature destruction of red blood cells. Erythrocytes can be destroyed too quickly or too early because of infection, because the hemoglobin produced is abnormal, because the spleen does not function properly, or because a person has been exposed to certain drugs or toxic chemicals. Red blood cells can have defects in the membrane that surrounds them, which leads to their destruction by macrophages. Hemolytic anemia also can be caused by problems with the immune system.

Sickle cell anemia and genetic causes

Sickle cell anemia is the most well-known type of hemolytic anemia. It is a genetic disease, meaning that a person inherits the genes ^* for the condition from his or her parents. If the person received only one copy of the affected gene (from one parent), he or she is said to have the sickle cell trait. A person who received the gene from both parents will have sickle cell disease. This type of anemia occurs most frequently in people of African ancestry. In the United States, 0.3% of the African-American population (over 50,000 people) has this disorder. People with sickle cell disease frequently have severe anemia, episodes of pain, delayed growth, and increased infections. People with sickle cell trait usually have no symptoms of anemia and grow and develop normally.

In a person with sickle cell anemia, the hemoglobin is different from that in healthy erythrocytes and it causes the red blood cells to be shaped like crescents. Because of this shape, they cannot easily flow through the bloodstream and they are destroyed faster than the body can replace them.

^* immune system fights germs and other foreign substances that enter the body.

^* genes are the material in the body that helps determine physical and mental characteristics, such as whether a person has brown hair or blue eyes.

Autoimmune diseases

People with autoimmune diseases, such as rheumatoid arthritis, can develop hemolytic anemia. In autoimmune diseases, the body's immune system does not work correctly. In addition to destroying foreign cells, such as bacteria that cause infection, the abnormal immune system attacks and destroys its own cells, including erythrocytes. In some people, drugs that reduce the immune system's activity (immunosuppressives) are used to treat anemia.

How Do People Know If They Are Anemic?

People who have mild anemia often have no symptoms. For people with more severe anemia, how they feel depends on how old they are, how fast the anemia developed, and what other illnesses they might have. If the anemia develops rapidly, a person is more likely to be aware of symptoms. If it develops over a long period of time, even people with moder-ate anemia may have few obvious symptoms.

Like Carrie, people with moderate to severe anemia may feel tired, weak, dizzy, and short of breath, all because the cells of the body are not getting enough oxygen. This lack of oxygen can cause them to be irritable and lose interest in what is going on around them. Sometimes people with moderate to severe anemia look pale and waxy, and some people develop a yellow color to the skin (jaundice) because of excess destruction of their red blood cells. They can also experience headaches, loss of appetite, indigestion, a sore tongue, bleeding gums, insomnia (difficulty sleeping), a rapid heartbeat, fatigue, and poor concentration. Some women experience menstrual period irregularities.

Doctors as Detectives: Diagnosing Anemia

Dealing with anemia can be a complex process. Determining if a patient is anemic is easy, but finding the underlying cause can be more difficult.

To test for anemia, a doctor usually orders a complete blood count (CBC). A technician or nurse takes a small sample of blood. The blood is tested for the amount of hemoglobin it contains and the numbers and volume of the different types of blood cells. Some of the blood also is smeared onto a slide so that the size of the cells can be measured and the color and shape of the blood can be gauged.

Once anemia has been confirmed, the doctor has to become a detective. The doctor finds clues by examining the patient and by asking the patient and his or her family about their medical history. Here are some of the questions the doctor may ask:

What Do Babies and
Teenage Girls Have
in Common?

Infants and teenage girls are at risk of developing iron-deficiency anemia. Teenage girls are at risk because they lose blood when they begin to menstruate and because they are undergoing growth spurts. These factors combined with an iron-poor diet (many teenage girls are concerned about their weight and how they look, so they go on diets that do not provide enough iron) often result in anemia.

Babies need lots of iron to fuel their rapid growth; their blood volume is expanding as quickly as the rest of their body is growing. Many doctors test 6-to 12-month-old babies for anemia, even if they seem to be happy and healthy, because historically, many babies developed iron-deficiency anemia between these ages. Today, only 2 to 3 percent of middle class infants develop anemia, and this is largely due to the iron added to baby formula and baby cereals. For breastfed babies, the iron in cereal or in supplements is especially important, because breast milk cannot provide enough iron. For older children and adults, adding a food with vitamin C, such as oranges, cantaloupe, or broccoli, helps the body to absorb the iron. Unfortunately, the rates of anemia are higher in poor communities because of poor nutrition.

Almost all cases of anemia can be identified by laboratory tests along with the patient's history and a physical examination.

Because the marrow is where blood cells are made, and it is here that many problems can occur, in a few cases a bone marrow sample may be needed in order to find the cause of the anemia. In this procedure, a needle is inserted into the hip bone to obtain a sample of bone marrow. It is then analyzed for the types and activities of the cells.

Anemia is the body's way of saying that something is wrong, and it should never be ignored. The doctor should always search for the underlying cause of anemia.

Scientific Research

Treatment of anemia depends entirely on the cause. Anemia gets a lot of scientific attention because it is a sign of so many different diseases and disorders. Research is focused both on better ways to diagnose anemia and on developing new ways to treat it. In some cases, anemia is difficult or impossible to treat.

For anemias caused by excessive or chronic bleeding, stopping blood loss is the first step. In some cases, a blood transfusion is used to replenish the volume of blood in the body. For people with dietary causes of anemia, eating a diet rich in the deficient nutrient or taking supplements such as iron or vitamins often fixes the problem.

Treatment for other anemias is more complex. For people with hemolytic anemias, finding out why the red blood cells are being destroyed prematurely is essential. In some people, the spleen must be removed to stop the premature destruction of erythrocytes.

One method of treating certain anemias caused by decreased production of red blood cells is to supply the body with erythropoietin (EPO). Different research groups have manufactured EPO to treat ane-mias caused by rheumatoid arthritis, HIV, kidney disease, and cancer. Other drugs are aimed at stimulating red cell production in people with sickle cell disease and some types of thalassemia.

Eating Right to Prevent
Anemia

Good nutrition plays a big part in preventing or treating many types of anemia. A healthy diet should include eating foods every day that contain: