Microcytic Anemias

Question 1

What is the cause of microcytic anemias?

Answer 1

Decreased production of hemoglobin

Question 2

Why is microcytosis seen in the presence of decreased hemoglobin?

Answer 2

RBCs must divide an extra time in order to try and maintain hemoglobin concentration, causing microcytic anemia

Question 3

What is the composition of heme?

Answer 3

Iron and protoporphyrin

Question 4

What are the 4 microcytic anemias?

Answer 4

1) iron deficiency anemia
2) anemia of chronic disease
3) sideroblastic anemia
4) thalassemia

Question 5

Anemia due to decreased levels of iron…

Answer 5

Iron deficiency anemia

Question 6

Where does the absorption of iron occur?

Answer 6

Duodenum

Question 7

How is iron transported across the cell membrane into the blood?

Answer 7

Enterocytes transport iron using ferroportin

Question 8

What substance is responsible for the transport of iron in the blood?

Answer 8

Transferrin

Question 9

Where does transferrin transport iron for storage?

Answer 9

To the liver and bone marrow macrophages

Question 10

What is stored intracellular iron bound to?

Answer 10

Ferritin

Question 11

What does the storage of iron bound ferritin prevent?

Answer 11

Free radical formation via the Fenton reaction

Question 12

What are the 4 laboratory measurements used to evaluate iron status in patients?

Answer 12

1) serum iron
2) Total iron-binding capacity (TIBC)
3) % saturation
4) Serum Ferritin

Question 13

What serum iron measuring?

Answer 13

Measure of iron in the blood

Question 14

What is total iron-binding capacity (TIBC) measuring?

Answer 14

Measure of transferrin molecules in the blood

Question 15

What is % saturation of iron measuring?

Answer 15

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

Question 16

What is serum ferritin measuring?

Answer 16

Iron stores in macrophages and the liver

Question 17

What is the most common cause of microcytic anemia seen in infants?

Answer 17

Breast-feeding—human milk is low in iron

Question 18

What is the most common cause of microcytic anemia in children?

Answer 18

Poor diet

Question 19

What is the most common cause of microcytic anemia in male adults ages 20-50?

Answer 19

Peptic ulcer disease

Question 20

What is the most common cause(s) of microcytic anemia in female adults ages 20-50?

Answer 20

Menorrhagia

Pregnancy

Question 21

What is the most common cause(s) of microcytic anemia in the elderly?

Answer 21

Colon polyps/carcinoma in Western world

Hookworm in developing world

Question 22

Malnutrition, malabsorption and gastrectomy are all causes of why type of anemia?

Answer 22

Microcytic anemia

Question 23

What is the first stage of iron deficiency?

Answer 23

Storage iron is depleted

Question 24

What are the laboratory values, with respect to ferritin and TIBC, in the first stage of iron deficiency?

Answer 24

Ferritin: decreased
TIBC: increased

NOTE: If ferritin is decreased then TIBC will be increased, ALWAYS

Question 25

What is the second stage of iron deficiency?

Answer 25

Serum iron is depleted

Question 26

What are the laboratory values, with respect to serum iron and % saturation of iron, in the second stage of iron deficiency?

Answer 26

Serum iron: decreased | % Saturation: decreased

Question 27

What is the third stage of iron deficiency?

Answer 27

Normocytic anemia

Question 28

Why is normocytic anemia seen in the third stage of iron deficiency?

Answer 28

The bone marrow is making fewer, but normal sized RBCs

Question 29

What is the fourth stage of iron deficiency?

Answer 29

Microcytic, hypochromic anemia—bone marrow is making smaller and fewer RBCs

Question 30

What are the clinical features of iron deficiency?

Answer 30

Anemia Koilonychia Pica

Question 31

What are the laboratory findings seen with iron deficiency anemia with respect to the following: RBCs, Ferritin, TIBC, serum iron, % saturation, and free erythrocyte protoporphyrin (FEP)?

Answer 31

``` RBCs: microcytic and hypochromic with increased red cell distribution width Ferritin: decreased TIBC: increased Serum iron: decreased % Saturation: decreased FEP: increased ```

Question 32

What is the treatment for iron deficiency microcytic anemia?

Answer 32

Supplemental iron—ferrous sulfate

Question 33

Iron deficiency anemia with esophageal web and atrophic glossitis that presents as anemia, dysphagia, and beefy-red tongue…

Answer 33

Plummer-Vinson syndrome