tailieunhanh - Chapter 098. Iron Deficiency and Other Hypoproliferative Anemias (Part 4)

Stages of Iron Deficiency Iron-deficiency anemia is the condition in which there is anemia and clear evidence of iron lack. The progression to iron deficiency can be divided into three stages (Fig. 98-2). The first stage is negative iron balance, in which the demands for (or losses of) iron exceed the body's ability to absorb iron from the diet. This stage results from a number of physiologic mechanisms, including blood loss, pregnancy (in which the demands for red cell production by the fetus outstrip the mother's ability to provide iron), rapid growth spurts in the adolescent, or inadequate dietary. | Chapter 098. Iron Deficiency and Other Hypoproliferative Anemias Part 4 Stages of Iron Deficiency Iron-deficiency anemia is the condition in which there is anemia and clear evidence of iron lack. The progression to iron deficiency can be divided into three stages Fig. 98-2 . The first stage is negative iron balance in which the demands for or losses of iron exceed the body s ability to absorb iron from the diet. This stage results from a number of physiologic mechanisms including blood loss pregnancy in which the demands for red cell production by the fetus outstrip the mother s ability to provide iron rapid growth spurts in the adolescent or inadequate dietary iron intake. Blood loss in excess of 10-20 mL of red cells per day is greater than the amount of iron that the gut can absorb from a normal diet. Under these circumstances the iron deficit must be made up by mobilization of iron from RE storage sites. During this period iron stores reflected by the serum ferritin level or the appearance of stainable iron on bone marrow aspirations decrease. As long as iron stores are present and can be mobilized the serum iron total iron-binding capacity TIBC and red cell protoporphyrin levels remain within normal limits. At this stage red cell morphology and indices are normal. Figure 98-2 Iron states Negative iron balance Iron-Oeiicienl erythropoiesis Iron deliciency anemia Erythron iron Marrow ifflFl stores t-3 0-1 ft 0 Seitini tarntin ugll 50 200 20 15 15 TIBC ug tJLI 300-360 360 380 400 Si pgMLj 50 150 NL 50 ao Saturation i 30-50 NL 20 10 Marrow sideroblasis 1 4 40-W NL 10 10 nee prcrtoporp-tiyrin ftfflW 30 50 NL 100 200 RBC morptiology NL NL NL Microcyl kJ hypochromic Souk f u i A3 K tp r OL. riunu ld e. St. Longo OL. J ri ion jl. L fc l o J Htrnsc-n s Pnn pfes 1 7th Edition http Copynght e Th Comp ni f. me. All ught fil rv d. Laboratory studies in the evolution of iron deficiency. Measurements of marrow iron stores serum ferritin and