5.2 Microcytic Anemias

Question 1

What is the MCV in microcytic anemias?

Answer 1

Less than 80

Question 2

What is the general problem in microcytic anemia?

Answer 2

Decreased production of Hb

Question 3

What some of the causes of microcytic anemia?

Answer 3

• Fe Deficiency
• Anemia of Chronic Disease
• Sideroblastic (defect of heme synthesis)
• Thalassemia (deficiency of globin)

Question 4

What is the most common type of anemia?

Answer 4

Fe Deficiency Anemia

Question 5

Where does Fe absorption occur?

Answer 5

Duodenum

Question 6

What is the Fe transport molecule?

Answer 6

Transferrin

Question 7

What is the Fe storage molecule?

Answer 7

Ferritin

Question 8

What is the common cause of Fe deficiency in an adult male?

Answer 8

Peptic Ulcer Disease

Question 9

What is the common cause of Fe deficiency in an adult female?

Answer 9

• Menorrhagia

- Pregnancy

Question 10

What is the common cause of Fe deficiency in an elderly adult?

Answer 10

Colon polyps or carcinoma in the West and Hookworm in 3rd world countries.

Question 11

What happens to the TIBC as ferritin decreases?

Answer 11

Increases

Question 12

What are the size of the RBCs in early Fe deficiency?

Answer 12

Normocytic Anemia - RBCs are made normally, but less are made due to deficiency

Question 13

What are the clinical features of Fe deficiency?

Answer 13

• Anemia
• Koilonychia
• Pica

Question 14

What will the value of the RDW be in Fe deficiency anemia?

Answer 14

Increased

Question 15

What is free erythrocyte protoporphyrin?

Answer 15

Free protoporphyrin that is indicative of Fe deficiency anemia due to Fe being decreased but protoporphyrin levels being normal.

Question 16

What is an associated syndrome with Fe deficiency anemia?

Answer 16

Plummer-Vinson Syndrome

Question 17

How does Plummer-Vinson Syndrome present?

Answer 17

Presents with anemia, dysphagia and beefy red tongue

Question 18

What is anemia of chronic disease associated with?

Answer 18

• Chronic Inflammation

- Cancer

Question 19

How does chronic disease lead to anemia?

Answer 19

Hepcidin sequesters Fe in storage site and limits Fe transfer from macrophages and it decreases EPO production.

Question 20

What is the function of hepcidin?

Answer 20

Sequesters Fe to prevent access by bacteria - response to inflammation

Question 21

How can ACD present in its early phase?

Answer 21

Normocytic Anemia

Question 22

Sideroblastic Anemia

Answer 22

Anemia due to defective protoporphyrin synthesis

Question 23

What is the rate limiting enzyme in the formation of protoporphyrin?

Answer 23

ALAS - cofactor is Vitamin B6

Question 24

Where in the cells is Fe attached to protoporphyrin?

Answer 24

Mitochondria

Question 25

What are the cells seen in sideroblastic anemia?

Answer 25

Ring Sideroblasts - Fe is in the mitochondria

Question 26

What is the defect in congenital sideroblastic anemia?

Answer 26

Defect in ALAS enzyme

Question 27

What are some acquired causes of sidroblastic anemia?

Answer 27

- Alcoholism - Lead Poisoning - Vitamin B6 Deficiency

Question 28

What drug can cause Vitamin B6 deficiency?

Answer 28

Isoniazid

Question 29

Thalassemia

Answer 29

Decreased synthesis of globin chains

Question 30

What is thalassemia protective against?

Answer 30

Plasmodium falciparum

Question 31

Components of HbF

Answer 31

alpha2 gamma2

Question 32

Components of HbA

Answer 32

alpha2 beta2

Question 33

Components of HbA2

Answer 33

alpha2 delta2

Question 34

What is the cause of alpha-thalassemia?

Answer 34

Due to a gene deletion - there are normally 4 alpha alleles on Ch16

Question 35

What happens with 1 alpha gene deletion?

Answer 35

Asymptomatic

Question 36

What happens with 2 alpha gene deletions?

Answer 36

Mild anemia with slightly increased RBC count

Question 37

Which deletion of 2 alpha genes is worse, cis or trans?

Answer 37

cis - it is due to an associated with an increased risk of severe thalassemia in offspring

Question 38

What group is the cis deletion of 2 alpha genes seen more often in?

Answer 38

Asians

Question 39

What group is the trans deletion of 2 alpha genes seen more often in?

Answer 39

Africans

Question 40

What happens with 3 alpha gene deletions?

Answer 40

Severe anemia with tetramers of HbH formed from beta chains that damage RBCs

Question 41

What happens with 4 alpha gene deletions?

Answer 41

Lethal in utero due to hydrops fetalis - gamma chains form tetramers called Hb Barts that damage RBCs

Question 42

What is the cause of beta-thalassemia?

Answer 42

Mutation of the beta genes on Ch11

Question 43

Beta Thalassemia Minor

Answer 43

1 normal beta and 1 beta + - Usually asymptomatic

Question 44

What cells are seen on smear of beta thalassemia minor?

Answer 44

Target Cells

Question 45

What is the key lab finding in beta thalassemia minor?

Answer 45

Increased HbA2

Question 46

Beta Thalassemia Major

Answer 46

2 beta 0 - Most severe and presents with anemia several months after birth as HbF is temporarily protective

Question 47

What will be seen on x-ray of a patient with beta thalassemia major?

Answer 47

Crew Cut Appearance

Question 48

What will be seen on blood smear of beta thalassemia major?

Answer 48

Hypochromic Target Cells

Question 49

What is the key lab finding of beta thalassemia major?

Answer 49

Little to no HbA