MLAB 1315- Hematology Keri Brophy-Martinez Unit 9: Iron Metabolism and Hypochromic Anemias

Iron Metabolism Primary function of iron is oxygen transport Iron absorption and storage is influenced by: The amount and type of available iron in the diet Incomplete absorption due to GI tract problems Current iron stores Increased demand (pregnancy, the growth years) Excessive loss due to acute or chronic hemorrhage menstrual period for women of childbearing years, GI bleeding for men

Clinical Syndromes of Iron Metabolism Iron Deficiency Anemia (IDA) This is the most common form of anemia. IDA occurs when the iron stores in the body are inadequate to preserve homeostasis. Peripheral blood smear in IDA is microcytic-hypochromic. If IDA is caused by bleeding, leukocytosis and thrombocytosis are possible. Typical lab findings in addition to low RBC, Hgb, Hct, MCV, MCH, MCHC: to normal retic Serum iron ↑ Total iron-binding capacity (TIBC) ↓ Serum ferritin

Clinical Syndromes of Iron Metabolism Dysfunction of Iron Utilization Usually this is due to an existing disease condition and is known as anemia of chronic disease. This will be discussed in a later section.

Clinical Syndromes of Iron Metabolism Iron Excess and Sideroblastic States Hemosiderosis - accumulation of excess iron in tissue macrophages which could be due to organ bleeding Hemochromatosis Hereditary condition caused by increased iron absorption which deposits in vital organs such as the liver, spleen and pancreas which then become fibrotic. People with this take on a bronze color. Therapy consists of iron removal by therapeutic phlebotomy or chelation

Clinical Syndromes of Iron Metabolism Iron Excess and Sideroblastic States Sideroblastic anemia Primary is genetic Secondary caused by: Certain therapeutic drugs Chronic transfusions (for aplastic anemia, leukemia, thalassemia) Alcoholism and food fads Use of iron utensils or increased iron in water Diagnostic lab finding is ringed sideroblasts in the bone marrow and Pappenheimer bodies in peripheral blood.

Clinical Syndromes of Iron Metabolism Iron Excess and Sideroblastic States Lead poisoning Lead interferes with iron storage in the mitochondria Lead damages the activity of enzymes used for heme synthesis (basophilic stippling)

Clinical Syndromes of Iron Metabolism Heme synthesis Porphyria - excessive production of porphyrins in the bone marrow (or liver) Rare disease caused by accumulation of porphyrins in developing RBC’s Characterized by dermal photosensitivy and rash caused by the sun. The original werewolf was probably a person with erythropoietic porphyria.