Anemia is a condition that develops when your blood doesn't have enough healthy red blood cells, which are responsible for transporting oxygen to your organs. It's the most prevalent blood condition in the United States, and affects an estimated 3.5 million Americans. Although many cases are mild and easily treated, anemia can range from mild to severe. Some forms are long term and even life threatening if not diagnosed and treated appropriately.
Types of Anemia
According to the National Institutes of Health's National Heart, Lung, and Blood Institute, there are more than 400 types of anemia. In general, the causes of these types of anemia can be divided into three groups:
• Anemia caused by blood loss.
• Anemia caused by decreased or faulty red blood cell production.
• Anemia caused by destruction of red blood cells.
Risk Factors For Anemia
Anyone can develop anemia, but there are many factors that may increase your risk for developing anemia, including:
• A diet lacking in iron, vitamin B12 and folate.
• A history of intestinal disorders (for example, Crohn's disease and celiac disease) that affect the absorption of nutrients.
• Blood loss due to menstruation.
• Chronic conditions such as cancer, renal or liver failure may increase one's risk of developing anemia, because these conditions may cause a decrease in red blood cells.
• A family history of an inherited anemia, such as sickle cell anemia.
• A history of certain infections, blood diseases, and autoimmune disorders.
• Exposure to toxic chemicals.
• Taking certain medications that affect red blood cell production and lead to anemia.
Causes of the Common Types of Anemia
There are many types of anemia.
• Iron-deficiency anemia is caused by a shortage of iron in the body. Your bone marrow needs iron to make hemoglobin, which is a protein molecule in the red blood cells. Without enough iron, the body can't produce enough hemoglobin for your red blood cells.
• Vitamin-deficiency anemia occurs when your diet lacks enough folate, vitamin B12 and other key nutrients. The body needs folate and vitamin B12 to produce enough healthy red blood cells. Sometimes people get enough B12 through their diets, but their bodies aren't able to process or absorb the vitamin. This can also lead to vitamin-deficiency anemia.
• Anemia of chronic disease is the result of certain chronic conditions such as cancer, HIV/AIDS, rheumatoid arthritis, Crohn's disease and other chronic inflammatory diseases. These medical conditions can interfere with the production of red blood cells, which in turn may cause chronic anemia. An individual with renal failure is often at risk for anemia.
• Aplastic anemia is considered to be a very rare, life-threatening anemia that is caused by a decrease in the bone marrow's ability to produce red blood cells. Infections, drugs and autoimmune diseases are considered to be common causes of aplastic anemia.
• Hemolytic anemia develops when the red blood cells are destroyed faster than the bone marrow can replace them. Hemolytic anemia can be inherited or develop later in life.
• Sickle cell anemia is an inherited condition in which the body makes sickle-shaped red blood cells. These irregularly shaped red blood cells die prematurely, resulting in a chronic shortage of red blood cells.
• Anemia associated with bone marrow disease can be caused by diseases such as leukemia. These diseases can cause anemia by affecting blood production in the bone marrow. The effects of these types of cancer and cancer-like disorders may range from a mild change in blood production to a complete, life-threatening shutdown of the blood-making process. Other cancers of the blood or bone marrow, such as multiple myeloma and lymphoma, can also cause anemia.
Signs and Symptoms
Initially, the symptoms associated with anemia may go unnoticed. They can increase in intensity as the anemia worsens. When a person does not have symptoms, anemia is often discovered during routine blood tests.