Ch5 - 2) Microcytic anemia Flashcards Preview

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Flashcards in Ch5 - 2) Microcytic anemia Deck (103)
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Microcytic anemias include

(1) iron deficiency anemia, (2) anemia of chronic disease, (3) sideroblastic anemia, and (4) thalassemia.


Iron deficiency anemia is due to?

decreased levels of iron -> dec heme -> dec hemoglobin —» microcytic anemia


What is the most common type of anemia?

iron deficiency anemia


What is the most common nutritional deficiency in the world?

Lack of iron, affecting roughly 1/3 of world's population


Iron is consumed in what forms?

heme (meat-derived) and non-heme (vegetable-derived) forms


Absorption of iron occurs in the?

duodenum, Enterocytes have heme and non-heme (DMT1) transporters; the heme form is more readily absorbed


How do enterocytes transport iron?

across the cell membrane into blood via ferroportin


How does transferrin transports iron?

in the blood and delivers it to liver and bone marrow macrophages for storage.


Stored intracellular iron is bound to what?

ferritin, which prevents iron from forming free radicals via the Fenton reaction


Laboratory measurements of iron status

1) serum iron 2)TIBC 3) % saturation 4) Serum ferritin


What does the serum iron measure?

Serum iron is a measure of iron in the blood


What does total iron-binding capacity (TIBC) measure?

transferrin molecules in the blood


What does % saturation of iron measure?

percentage of transferrin molecules that are bound by iron (normal is 33%)


What does serum ferritin measure?

reflects iron stores in macrophages and the liver


What is iron deficiency is usually caused by?

dietary lack or blood loss


What is iron deficiency is usually caused by in infants?

breast-feeding (human milk is low in iron)


What is iron deficiency is usually caused by in children?

poor diet


What is iron deficiency is usually caused by in adults?

(20-50 years old)—peptic ulcer disease in males and menorrhagia or pregnancy in females


What is iron deficiency is usually caused by in elderly?

colon polyps/carcinoma in the Western world; hookworm (Ancylostoma duodenale and Nieator americanus) in the developing world


What are some other causes for iron deficiency?

malnutrition, malabsorption, and gastrectomy (acid aids iron absorption by maintaining the Fe2+ state, which is more readily absorbed


What are the stages of iron deficiency?

1. Storage iron is depleted— decreased serum ferritin; increased TIBC (transferrin) 2. Serum iron is depleted— dec serum iron; dec % saturation 3. Normocytic anemia—Bone marrow makes fewer, but normal-sized, RBCs 4. Microcytic, hypochromic anemia—Bone marrow makes smaller and fewer RBC's


The initial stage of iron deficiency results in what type of anemia?

normocytic anemia b/c the bone marrow's initial response is to make as many normal RBC's as possible


what are the clinical features of iron deficiency

anemia, koilonychia, and pica.


Laboratory findings for iron deficiency include?

microcytic, hypochromic RBCs with increased red cell distribution width increased RDW, 2. decreased ferritin; inc TIBC; dec serum iron; dec % saturation 3. inc Free erythrocyte protoporphyrin (FEP


What is FEP?

free erythrocyte protoporphoryin - decreased Fe means less protoporphorin is bound producing heme.


Why do you have increased RDW in iron deficiency?

initial response of bone marrow is to produce as many normal RBC's as possible, after the anemia progresses it produces small RBC's - varying sizes means increased RDW


What is RDW?

red blood cell distribution width, measures the spectrum of size of the RBC's


What does a low RDW mean?

all of the red blood cells have the same size


What does a high RDW mean?

RBC's have diffent sizes


What is the treatment for iron deficiency anemia?

involves supplemental iron (ferrous sulfate) - always ask why is the pt iron deficient