TAILIEUCHUNG - Chapter 058. Anemia and Polycythemia (Part 1)

Cytoplasmic maturation defects result from severe iron deficiency or abnormalities in globin or heme synthesis. Iron deficiency occupies an unusual position in the classification of anemia. If the iron-deficiency anemia is mild to moderate, erythroid marrow proliferation is decreased and the anemia is classified as hypoproliferative. However, if the anemia is severe and prolonged, the erythroid marrow will become hyperplastic despite the inadequate iron supply, and the anemia will be classified as ineffective erythropoiesis with a cytoplasmic maturation defect. In either case, an inappropriately low reticulocyte production index, microcytosis, and a classic pattern of iron values make the diagnosis. | Chapter 058. Anemia and Polycythemia Part 1 Cytoplasmic maturation defects result from severe iron deficiency or abnormalities in globin or heme synthesis. Iron deficiency occupies an unusual position in the classification of anemia. If the iron-deficiency anemia is mild to moderate erythroid marrow proliferation is decreased and the anemia is classified as hypoproliferative. However if the anemia is severe and prolonged the erythroid marrow will become hyperplastic despite the inadequate iron supply and the anemia will be classified as ineffective erythropoiesis with a cytoplasmic maturation defect. In either case an inappropriately low reticulocyte production index microcytosis and a classic pattern of iron values make the diagnosis clear and easily distinguish iron deficiency from other cytoplasmic maturation defects such as the thalassemias. Defects in heme synthesis in contrast to globin synthesis are less common and may be acquired or inherited Chap. 352 . Acquired abnormalities are usually associated with myelodysplasia may lead to either a macro- or microcytic anemia and are frequently associated with mitochondrial iron loading. In these cases iron is taken up by the mitochondria of the developing erythroid cell but not incorporated into heme. The iron-encrusted mitochondria surround the nucleus of the erythroid cell forming a ring. Based on the distinctive finding of so-called ringed sideroblasts on the marrow iron stain patients are diagnosed as having a sideroblastic anemia almost always reflecting myelodysplasia. Again studies of iron parameters are helpful in the differential diagnosis and management of these patients. Blood Loss Hemolytic Anemia In contrast to anemias associated with an inappropriately low reticulocyte production index hemolysis is associated with red cell production indices times normal. The stimulated erythropoiesis is reflected in the blood smear by the appearance of increased numbers of polychromatophilic macrocytes. A marrow

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