Anemia
What Is Anemia?
Anemia (uh-NEE-me-eh) is a condition in which your blood has a lower than normal number of red blood cells. This condition also can occur if your red blood cells don’t contain enough hemoglobin (HEE-muh-glow-bin). 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.
If you have anemia, your body doesn’t get enough oxygen-rich blood. As a result, you may feel tired and have other symptoms. With severe or long-lasting anemia, the lack of oxygen in the blood can damage the heart, brain, and other organs of the body. Very severe anemia may even cause death.
Overview
Red blood cells are disc-shaped and look like doughnuts without holes in the center. They carry oxygen and remove carbon dioxide (a waste product) from your body. These cells are made in the bone marrow—a sponge-like tissue inside the bones. Red blood cells live for about 120 days in the bloodstream and then die.
White blood cells and platelets (PLATE-lets) also are made in the bone marrow. White blood cells help fight infection. Platelets stick together to seal small cuts or breaks on the blood vessel walls and stop bleeding. With some types of anemia, you may have low numbers of all three types of blood cells.
Anemia has three main causes: blood loss, lack of red blood cell production, or high rates of red blood cell destruction. These causes may be due to a number of diseases, conditions, or other factors.
Outlook
Many types of anemia can be mild, short term, and easily treated. Some types can even be prevented with a healthy diet. Other types can be treated with dietary supplements.
However, certain types of anemia may be severe, long lasting, and life threatening if not diagnosed and treated.
If you have signs and symptoms of anemia, you should see your doctor to find out whether you have the condition. Treatment will depend on what has caused the anemia and how severe it is.
What Causes Anemia?
The three main causes of anemia are:
* Blood loss
* Lack of red blood cell production
* High rates of red blood cell destruction
Some people have anemia due to more than one of these factors.
Blood Loss
Blood loss is the most common cause of anemia, especially iron-deficiency anemia. Blood loss can be short term or persist over time.
Heavy menstrual periods or bleeding in the digestive or urinary tract can cause blood loss. Surgery, trauma, or cancer also can cause blood loss.
If a lot of blood is lost, the body may lose enough red blood cells to cause anemia.
Lack of Red Blood Cell Production
Both acquired and inherited conditions and factors can prevent your body from making enough red blood cells. “Acquired” means you aren’t born with the condition, but you develop it. “Inherited” means your parents passed the gene for the condition on to you.
Examples of acquired conditions and factors that can prevent your body from making enough red blood cells include diet, hormones, some chronic (ongoing) diseases, and pregnancy.
Aplastic anemia also can prevent your body from making enough red blood cells. This condition can be acquired or inherited.
Diet
A diet that lacks iron, folic acid (folate), or vitamin B12 can prevent your body from making enough red blood cells. Your body also needs small amounts of vitamin C, riboflavin, and copper to make red blood cells.
Conditions that make it hard for your body to absorb nutrients also can cause your body to make too few red blood cells.
Hormones
Your body needs the hormone erythropoietin (eh-rith-ro-POY-eh-tin) to make red blood cells. This hormone stimulates the bone marrow to make these cells. A low level of this hormone can lead to anemia.
Diseases and Disease Treatments
Chronic (long-term) diseases, like kidney disease and cancer, can make it hard for the body to make enough red blood cells.
Some cancer treatments may damage the bone marrow or damage the red blood cells’ ability to carry oxygen. If the bone marrow is damaged, it can’t make red blood cells fast enough to replace the ones that died or were destroyed.
People who have HIV/AIDS may develop anemia due to infections or medicines used to treat their diseases.
Pregnancy
Anemia can occur during pregnancy due to low levels of iron and folic acid (folate) and changes in the blood.
During the first 6 months of pregnancy, the fluid portion of a woman’s blood (the plasma) increases faster than the number of red blood cells. This dilutes the blood and can lead to anemia.
Aplastic Anemia
Some infants are born without the ability to make enough red blood cells. This condition is called aplastic anemia. Infants and children who have aplastic anemia often need blood transfusions to increase the number of red blood cells in their blood.
Acquired conditions or factors, such as certain medicines, toxins, and infectious diseases, also can cause aplastic anemia.
High Rates of Red Blood Cell Destruction
Both acquired and inherited conditions and factors can cause your body to destroy too many red blood cells.
One example of an acquired condition that can cause your body to destroy too many red blood cells is an enlarged or diseased spleen. The spleen is an organ that removes worn-out red blood cells from the body. If the spleen is enlarged or diseased, it may remove more red blood cells than normal, causing anemia.
Examples of inherited conditions that can cause your body to destroy too many red blood cells include sickle cell anemia, thalassemias, and lack of certain enzymes. These conditions create defects in the red blood cells that cause them to die faster than healthy red blood cells.
Hemolytic anemia is another example of a condition in which your body destroys too many red blood cells. Inherited conditions can cause this type of anemia. Acquired conditions or factors, such as immune disorders, infections, certain medicines, or reactions to blood transfusions, also can cause hemolytic anemia.
Who Is At Risk for Anemia?
Populations Affected
Anemia is a common condition. It occurs in all age groups and all racial and ethnic groups. Both men and women can have anemia, but women of childbearing age are at higher risk for the condition. This is because women in this age range lose blood from menstruation.
Anemia can develop during pregnancy due to low levels of iron and folic acid (folate) and changes in the blood. During the first 6 months of pregnancy, the fluid portion of a woman’s blood (the plasma) increases faster than the number of red blood cells. This dilutes the blood and can lead to anemia.
Infants younger than 2 years old also are at risk for anemia. This is because they may not get enough iron in their diets, especially if they drink a lot of cow's milk. Cow's milk is low in the iron needed for growth. Drinking too much cow’s milk may keep an infant or toddler from eating enough iron-rich foods. It also may keep his or her body from absorbing iron from iron-rich food.
Researchers continue to study how anemia affects older adults. More than 10 percent of older adults have mild forms of anemia. Many of these people have other medical conditions as well.
Major Risk Factors
Factors that raise your risk for anemia include:
* A diet that is low in iron, vitamins, or minerals
* Blood loss from surgery or an injury
* Long-term or serious illnesses, such as kidney disease, cancer, diabetes, rheumatoid arthritis, HIV/AIDS, inflammatory bowel disease (including Crohn’s disease), liver disease, heart failure, and thyroid disease
* Long-term infections
* A family history of inherited anemia, such as sickle cell anemia or thalassemias
What Are the Signs and Symptoms of Anemia?
The most common symptom of anemia is fatigue (feeling tired or weak). If you have anemia, it may seem hard to find the energy to do normal activities.
Other signs and symptoms of anemia include:
* Shortness of breath
* Dizziness
* Headache
* Coldness in the hands and feet
* Pale skin
* Chest pain
These signs and symptoms can occur because your heart has to work harder to pump more oxygen-rich blood through your body.
Mild to moderate anemia may cause very mild symptoms or none at all.
Complications of Anemia
Some people who have anemia may have arrhythmias (ah-RITH-me-ahs). An arrhythmia is a problem with the rate or rhythm of the heartbeat. Over time, arrhythmias can damage your heart and possibly lead to heart failure. Anemia also can damage other organs in your body because your blood can’t get enough oxygen to them.
Anemia can weaken people who have cancer or HIV/AIDS. This can make their treatments not work as well.
Anemia also can cause many other medical problems. People who have kidney disease and anemia are more likely to have heart problems. In some types of anemia, too little fluid intake or too much loss of fluid in the blood and body can occur. Severe loss of fluid can be life threatening.
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