Overview of Anemia

Anemia may be caused by excessive bleeding Anemia Due to Excessive Bleeding Anemia due to excessive bleeding results when loss of red blood cells exceeds production of new red blood cells. When blood loss is rapid, blood pressure falls, and people may be dizzy. When... read more . Bleeding may be sudden, as may occur as a result of an injury or during surgery. Often, bleeding is gradual and repetitive (chronic bleeding), typically due to abnormalities in the digestive or urinary tract or heavy menstrual periods Abnormal Uterine Bleeding (AUB) Abnormal uterine bleeding in women of childbearing age is bleeding from the uterus that does not follow the normal pattern for menstrual cycles. That is, it occurs too frequently or irregularly... read more . Chronic bleeding typically leads to low levels of iron, which leads to worsening anemia (see Iron Deficiency Anemia Iron Deficiency Anemia Iron deficiency anemia results from low or depleted stores of iron, which is needed to produce red blood cells. Excessive bleeding is the most common cause. People may be weak, short of breath... read more ).

Anemia may also result when the body does not produce enough red blood cells (see also Formation of Blood Cells Formation of Blood Cells Red blood cells, most white blood cells, and platelets are produced in the bone marrow, the soft fatty tissue inside bone cavities. Two types of white blood cells, T and B cells ( lymphocytes)... read more ). Many nutrients are needed for red blood cell production. The most critical are iron, vitamin B12, and folate (folic acid), but the body also needs trace amounts of copper, as well as a proper balance of hormones, especially erythropoietin (a hormone that stimulates red blood cell production). Without these nutrients and hormones, production of red blood cells is slow and inadequate, or the red blood cells may be deformed and unable to carry oxygen adequately.

Chronic inflammation, infection, or cancer also may suppress red blood cell production. In other circumstances, the bone marrow space may be invaded and replaced (for example, by leukemia Overview of Leukemia Leukemias are cancers of white blood cells or of cells that develop into white blood cells. White blood cells develop from stem cells in the bone marrow. Sometimes the development goes awry... read more , lymphoma Overview of Lymphoma Lymphomas are cancers of lymphocytes, which reside in the lymphatic system and in blood-forming organs. Lymphomas are cancers of a specific type of white blood cells known as lymphocytes. These... read more , or metastatic cancer), resulting in decreased production of red blood cells.

Anemia may also result when too many red blood cells are destroyed. Normally, red blood cells live about 120 days. Scavenger cells in the bone marrow, spleen, and liver detect and destroy red blood cells that are near or beyond their usual life span. If red blood cells are destroyed prematurely (hemolysis), the bone marrow tries to compensate by producing new cells faster. When destruction of red blood cells exceeds their production, hemolytic anemia results. Hemolytic anemia Autoimmune Hemolytic Anemia Autoimmune hemolytic anemia is a group of disorders characterized by a malfunction of the immune system, resulting in the production of autoantibodies that attack red blood cells as if they... read more is relatively uncommon compared with the anemia caused by excessive bleeding and decreased red blood cell production. Hemolytic anemia may result from disorders of the red blood cells themselves, but more often it results from other disorders that cause red blood cells to be destroyed.

Many disorders that cause anemia, such as cancer, including blood cancers such as myelodysplastic syndrome Myelodysplastic Syndrome (MDS) Myelodysplastic syndrome refers to a group of related disorders in which abnormal blood-forming cells develop in the bone marrow. At first, these cells interfere with the production of normal... read more and multiple myeloma Multiple Myeloma Multiple myeloma is a cancer of plasma cells in which abnormal plasma cells multiply uncontrollably in the bone marrow and occasionally in other parts of the body. People often have bone pain... read more , tend to be more common among older people. Thus, many older people develop anemia. Anemia of chronic disease Anemia of Chronic Disease In anemia of chronic disease, inflammation caused by a chronic disorder slows the production of red blood cells and sometimes decreases survival of red blood cells. (See also Overview of Anemia... read more (caused by chronic inflammation, infection, or cancer) and iron deficiency anemia Iron Deficiency Anemia Iron deficiency anemia results from low or depleted stores of iron, which is needed to produce red blood cells. Excessive bleeding is the most common cause. People may be weak, short of breath... read more caused by abnormal bleeding are the most common causes of anemia among older people. Anemia is not a normal consequence of aging, and a cause should always be sought when anemia is identified.

Symptoms of anemia are basically the same regardless of age. Also, even when anemia is mild, older people are more likely to become confused, depressed, agitated, or listless than younger people. They may also become unsteady and have difficulty walking. These problems can interfere with being able to live independently. However, some older people with mild anemia have no symptoms at all, particularly when anemia develops gradually, as it often does.

In older people, anemia caused by vitamin B12 deficiency may be mistaken for dementia Dementia Dementia is a slow, progressive decline in mental function including memory, thinking, judgment, and the ability to learn. Typically, symptoms include memory loss, problems using language and... read more because this type of anemia may affect mental function.

Having anemia may shorten the life expectancy of older people. Thus, identifying the cause and correcting it are particularly important.