What is Anemia?
[[File:Iron deficiency anemia blood film.jpg|thumb|Blood film with iron deficiency anemia.]] [[File:Sickle cell anemia.jpg|thumb|Sickle cell anemia. Normal red blood cells are shown in Figure 1; with sickle cell anemia, red blood cells look like figure 2]] '''Anemia''' (U.S. spelling) or '''anaemia''' is the most common blood disorder. It is caused by not having enough [[red blood cell]]s or [[hemoglobin]] in the [[blood]]. == Types (and causes) of anemia according to size of red blood cells == === Microcytic anemia === Microcytic anemia develops when red blood cells are smaller than usual because they don’t contain enough hemoglobin. Hemoglobin is a protein in red blood cells responsible for carrying oxygen to different parts of the body. * [[Iron deficiency anemia]] is the most common type of anemia overall * [[hemoglobinopathy|Hemoglobinopathies]]—much rarer ** [[Sickle-cell disease]] (once called ''sickle-cell anemia'') ** [[Thalassemia]] === Normocytic anemia === Normocytic anemia occurs when the number of red blood cells is lower than normal, and those cells contain less hemoglobin than they should. This type of anemia is often caused by an underlying chronic condition. Treatment for normocytic anemia typically involves addressing the underlying illness. * Acute [[hemorrhage|blood loss]] * [[Anemia of chronic disease]] * [[Aplastic anemia]] ([[bone marrow]] failure) === Macrocytic anemia === Macrocytic anemia is a blood condition where the bone marrow produces unusually large red blood cells. These oversized cells lack the necessary nutrients to function properly. While macrocytic anemia itself is not a severe condition, it can lead to serious health complications if left untreated. * [[Megaloblastic anemia]] due to not having enough of either [[vitamin B12]] or [[folic acid]] (or both) * [[Pernicious anemia]] is an [[autoimmune]] problem with the [[parietal cell]]s of the stomach * [[Alcoholism]] * [[Methotrexate]], [[zidovudine]], and other drugs that stop [[DNA replication]]. This is the most common