What is anemia? What are the four main types of anemia?
Anemia is low concentration of hemoglobin in the blood. The four main types of anemia are the nutrient-deficiency anemia, anemia caused by blood loss, hemolytic anemia and aplastic anemia. Nutrient-deficiency anemia is caused by dietary deficiency of fundamental nutrients for the production or functioning of the red blood cells, like iron (iron deficiency anemia), vitamin B12 and folic acid. Anemia caused by blood loss occurs in hemorrhagic conditions or in diseases like peptic ulcerations and hookworm disease. Hemolytic anemia is caused by excessive destruction of red blood cells, for example, in diseases like malaria or in hypervolemic conditions (excessive water in blood that causes lysis of red blood cells). Aplastic anemia occurs from deficiencies of the hematopoiesis and it happens when the bone marrow is injured by cancers from other tissues (metastasis), by autoimmune diseases and by intoxication from drugs (like sulfas and anticonvulsants) or by chemical substances (like benzene, insecticides, paints, herbicides and solvents in general). Some genetic diseases also affect the bone marrow causing aplastic anemia.
