Anemia and iron deficiency are two common terms that go hand in hand mainly because the commonest cause of anemia is iron deficiency. However, there is a lot more to anemia than iron deficiency. Therefore, it is important to understand the differences between the two terms.
Anemia is defined medically as having below normal hemoglobin levels for the age and health status. In general, the lowest normal hemoglobin concentration is 10mg/dl. Hemoglobin is the red pigment in the red blood cells. It is made up of four globin chains and four heme groups. Hemoglobin is the oxygen transport system in blood. One hemoglobin molecule can bind to four oxygen molecules. Hemoglobin binds with oxygen when the oxygen partial pressure is high, and releases bound oxygen, where it is low. Therefore, physiologically there are two types of hemoglobin. They are deoxygenated and oxygenated hemoglobin. When the amount of deoxygenated hemoglobin is high, the skin turns a light shade of blue, and this is called cyanosis. Normal oxygen partial pressures in blood shift between 10.5 KPa to 13.5 KPa. Normal carbon dioxide levels shift between 4.5 KPa to 6 KPa. Anemia can be due to many causes.
What causes anemia can be poor production of hemoglobin; abnormal production or excessive loss. Red blood cells are made in the bone marrow of adults. Bone marrow diseases lead to poor production (aplastic anemia). Lack of body iron slows down red blood cell production and excessive blood loss leads to low body iron (iron deficiency anemia). Abnormal production leads to hemoglobinopathies. Excessive red blood cell destruction leads to hemolytic anemia. Long lasting diseases may give rise to anemia of chronic diseases.
All these types of anemia share a common set of symptoms and signs. Patients with any type of anemia will present with lethargy, reduced exercise tolerance, weakness and paleness. They may also have chest pain if anemia is severe enough. In addition to common features, menorrhagia, hematemesis, melena, hemorrhoids, hemoptysis, poor clotting, bone pain, recurrent infection, angular stomatitis, coated tongue, jaundice, dark urine and dark stools may be there. A full blood count will show low hemoglobin. There are many types of anemia depending on the size, morphology and hemoglobin concentration in red blood cells. Small red blood cells (microcytic), large red blood cells (macrocytic), and poorly staining red blood cells (hypochromic) are the common types. A blood picture will help in differentiating between the types. Iron studies will show the status of body iron stores. Vit B, folic acid levels, serum bilirubin, urinalysis, bone marrow biopsy may be needed to come to a definitive diagnosis in difficult cases. In all types of anemia, iron replacement is vital. If needed vitamin B, C, folic acid and blood transfusion may be administered.
Iron deficiency is having a below normal iron stores for the physiological status. Expected iron store values are different in females, males, pregnancy and lactation. Iron deficiency may be due to poor input, excessive loss, and excessive utilization. Diet containing poor iron content, enteropathies leading to loss of gut lining cells, and excessive production of red blood cells due to a secondary cause may lead to iron deficiency. Serum iron, ferritin, and iron binding protein levels are important to assess iron stores. Iron deficiency anemia is a result of low body iron and blood loss.
What is the difference between Anemia and Iron Deficiency?
• Anemia is low hemoglobin concentration while iron deficiency is low body iron levels.
• Anemia is a known result of iron deficiency.