Anemia is defined as a low number of red blood cells. In a routine blood test, anemia is reported as a low hemoglobin or hematocrit. Hemoglobin is the main protein in red blood cells. It carries oxygen, and delivers it throughout your body.
If you have anemia, your hemoglobin level will be low too. If it is low enough, your tissues or organs may not get enough oxygen. Symptoms of anemia like, fatigue or shortness of breath, happen because your organs aren't getting what they need to work the way they should.
What are the symptoms of Anemia?
The signs of anemia can be so mild that you might not even notice them. At a certain point, as your blood cells decrease, symptoms often develop. Depending on the cause of the anemia, symptoms may include:
Dizziness, lightheadedness, or feeling like you are about to pass out
Different types of anemia have different causes. They include:
Iron deficiency anemia. This most common type of anemia is caused by a shortage of iron in your body. Your bone marrow needs iron to make hemoglobin. Without adequate iron, your body can't produce enough hemoglobin for red blood cells. Without iron supplementation, this type of anemia occurs in many pregnant women. It is also caused by blood loss, such as from heavy menstrual bleeding, an ulcer, cancer and regular use of some over-the-counter pain relievers, especially aspirin, which can cause inflammation of the stomach lining resulting in blood loss.
Vitamin deficiency anemia. Besides iron, your body needs folate and vitamin B-12 to produce enough healthy red blood cells. A diet lacking in these and other key nutrients can cause decreased red blood cell production. Also, some people who consume enough B-12 aren't able to absorb the vitamin. This can lead to vitamin deficiency anemia, also known as pernicious anemia.
Anemia of inflammation. Certain diseases-such as cancer, HIV/AIDS, rheumatoid arthritis, kidney disease, Crohn's disease and other acute or chronic inflammatory diseases-can interfere with the production of red blood cells.
Aplastic anemia. This rare, life-threatening anemia occurs when your body doesn't produce enough red blood cells. Causes of aplastic anemia include infections, certain medicines, autoimmune diseases and exposure to toxic chemicals.
Anemias associated with bone marrow disease. A variety of diseases, such as leukemia and myelofibrosis, can cause anemia by affecting blood production in your bone marrow. The effects of these types of cancer and cancer-like disorders vary from mild to life-threatening.
Hemolytic anemias. This group of anemias develops when red blood cells are destroyed faster than bone marrow can replace them. Certain blood diseases increase red blood cell destruction. You can inherit a hemolytic anemia, or you can develop it later in life.
Sickle cell anemia. This inherited and sometimes serious condition is a hemolytic anemia. It's caused by a defective form of hemoglobin that forces red blood cells to assume an abnormal crescent (sickle) shape. These irregular blood cells die prematurely, resulting in a chronic shortage of red blood cells.
What are the risk factors for Anemia?
These factors place you at increased risk of anemia:
A diet lacking in certain vitamins and minerals. A diet consistently low in iron, vitamin B-12 and folate increases your risk of anemia.
Intestinal disorders. Having an intestinal disorder that affects the absorption of nutrients in your small intestine-such as Crohn's disease and celiac disease-puts you at risk of anemia.
Menstruation. In general, women who haven't had menopause have a greater risk of iron deficiency anemia than do men and postmenopausal women. Menstruation causes the loss of red blood cells.
Pregnancy. If you're pregnant and aren't taking a multivitamin with folic acid and iron, you're at an increased risk of anemia.
Chronic conditions. If you have cancer, kidney failure, diabetes or another chronic condition, you could be at risk of anemia of chronic disease. These conditions can lead to a shortage of red blood cells. Slow, chronic blood loss from an ulcer or other source within your body can deplete your body's store of iron, leading to iron deficiency anemia.
Family history. If your family has a history of an inherited anemia, such as sickle cell anemia, you also might be at increased risk of the condition.
Other factors. A history of certain infections, blood diseases and autoimmune disorders increases your risk of anemia. Alcoholism, exposure to toxic chemicals, and the use of some medications can affect red blood cell production and lead to anemia.
Age. People over age 65 are at increased risk of anemia.