Anemia occurs when the amount of hemoglobin (found in the red blood cells) drops below normal. Hemoglobin is necessary for the transport and delivery of oxygen throughout the body. There are many different types of anemia, but we will limit this page to the most common ones.
Iron and Vitamin Deficiencies
Iron deficiency anemia is the most common of the anemias and is usually due to bleeding. In women, iron deficiency may be due to heavy menstrual periods, but in older women and in men, the bleeding is usually from disease of the intestines. In children and in pregnant women, the body needs more iron, and iron deficiency may be due simply to not eating enough iron in the diet. Iron deficiency may also result from some extreme diets. Treatment of iron deficiency usually involves iron supplements. In older women and in men, there is usually also some further testing to determine the reasons for the abnormal blood loss.
Pregnant and nursing women frequently develop this deficiency since the baby requires large amounts of iron for growth. Lack of iron can lead to low birth weight babies and premature delivery. Pre-pregnant and pregnant women are routinely given iron supplements to prevent these complications. Newborns who are nursing from deficient mothers tend to have iron deficiency anemia as well.
Blood tests may show a normal or low hemoglobin, decreased iron, low ferritin, and abnormal red blood cell indices. The total iron-binding capacity (TIBC) or transferrin will be increased. The ferritin test is considered to be the most specific for identifying iron deficiency anemia, unless infection or inflammation are present.
Vitamin B12 deficiency is less common than iron deficiency and is usually not due to dietary deficiency of vitamin B12. The most common cause is a disease called pernicious anemia, in which the body stops making a substance (called “intrinsic factor”) that is needed to absorb vitamin B12 from the diet. Vitamin B12 deficiency can also cause nerve problems, often causing numbness and tingling that start first in the hands and feet. Hemoglobin is low, but red blood cells are abnormally large.
Folic acid deficiency can cause the same pattern of changes in hemoglobin and red cell indices as does vitamin B12 deficiency. Folic acid is found in many foods, especially in green, leafy vegetables. Folic acid is also added to most grain products in the United States so that deficiency in folic acid is rarely seen in the U.S. today. During pregnancy, however, there is an increased need for folic acid so deficiency can develop during this time. This is especially dangerous because deficiency in folic acid can cause problems in the development of the brain and spinal cord of the baby. Pregnant women usually need folic acid supplements.
Aplastic anemia is a rare disease, caused by a decrease in the number of blood cells produced due to bone marrow failure. Symptoms of aplastic anemia include prolonged bleeding and the frequent appearance of bruises due to decreased platelets, pale skin color and fatigue from decreased hemoglobin, and increased number and severity of infections due to a low white blood cell count. The differential white blood count shows a decrease in all types of cells (pancytopenia). A bone marrow aspiration will show a decrease in the number of mature cells. Treatment depends on the cause. Blood transfusions and a bone marrow transplant may be needed in severe cases.