Microcytic Anemias (Part 1)

Question 1

MCV classification and cause of microcytosis and microcytic anemia

Answer 1

MCV < 80 um^3, due to extra RBC division in order to maintain normal concentration of Hb, due to decreased production of Hb (1. Iron deficiency 2. Anemia of chronic disease 3. sideroblastic anemia (low protoporphyrin) 4. thalassemia (low globin production))

Question 2

What is the most common type of anemia?

Answer 2

Iron deficiency anemia

Question 3

Where in the body is iron absorbed? Which form of iron is more readily absorbed?

Answer 3

In the duodenum via enterocytes in heme and non-heme forms; Heme form more readily absorbed.

Question 4

Describe the process of iron absorption, transport within the blood and storage

Answer 4

Iron transported across cell membrane into blood via ferroportin. Transported within blood via transferrin and is stored within liver and bone marrow macrophages bound to ferritin.

Question 5

Why is the binding and storage of iron within the body important?

Answer 5

Prevent iron forming free radicals via the Fenton rxn

Question 6

4 laboratory measures of iron status within the body

Answer 6

Serum iron - iron in the blood, Total iron binding capacity (TIBC) - number of transferrin molecules in the blood, % saturation - % transferrin molecules bound to iron, serum ferritin - reflects iron stores in macrophages and liver

Question 7

Typical presentations of iron deficiency

Answer 7

Usually dietary or blood loss. 1) Infants (low iron in breast milk) 2) Children with poor diet 3) Adults (PUD or menorrhagia/pregnancy) 4) Elderly: Western world: colon polyps/carcinoma, developing world: hookworm (Ancylostoma duodenale and Necator americanus) 5) gastrectomy (Acid environment maintains absorbable Fe2+ state), malabsorption, malnutrition

Question 8

4 Stages of iron deficiency

Answer 8

1. Storage iron is depleted - decrease ferritin, increase TIBC (more transferrin made) 2. Depleted serum iron - decreased serum iron and decreased % sat 3. Normocytic anemia - fewer normal sized RBCs 4. Microcytic hypochromic anemia - BM makes smaller and fewer RBCs

Question 9

Clinical presentation of iron deficiency

Answer 9

Anemia, koilonychia (spoon-shaped nails), pica (chewing random shit)

Question 10

Lab findings of microcytic anemia

Answer 10

ucytic hypochromic RBCs with increased RDW, ferritin decrease, TIBC increase, serum iron decrease, % sat decrease, free erythrocyte protoporphytin (FEP) increase

Question 11

Tx for microcytic anemia

Answer 11

Ferrous sulfate

Question 12

What is Plummer-Vinson syndrome?

Answer 12

Iron deficiency anemia with esophageal web and atrophic glossitis - anemia dysphagia and beefy red tongue