Microcytic Anemia

Question 1

Alpha-thalassemia is caused by

β-thalassemia is caused by

Answer 1

alpha: allele deletions (4 possible)

β: allele mutations (2 possible)

Question 2

Crew cut skull on X-ray pathopneumonic for

Answer 2

β-thalassemia

due to extreme extramedullary hematopoesis in skull

Question 3

What type of thalassemia is at risk for aplastic crisis with parvo-B19 infection

Answer 3

β-thalassemia major

Question 4

Subtypes of β-thalassemia

Answer 4

β-thalassemia minor: usually asymptomatic, HbA2 (alpha2delta2) increased
β-thalassemia major: absent HbA, severe extramedullary hematopoesis (crew cut X-ray), transfusion-dependent, 2˚ hemochromotosis

Question 5

What are the three types of normal Hb in people

Answer 5

HbF: α2γ2
HbA:α2β2
HbA2:α2δ2 (elevated in beta-thalassemia minor)

Question 6

This type of microcytic anemia becomes symptomatic only after 6 months of age

Answer 6

β-thalassemia major

because HbF predominates until then

Question 7

α-thalassemia is protective against infection with which organism

Answer 7

Plasmodium falcipara

Question 8

What type of globin is found in all types of Hb

Answer 8

α-globin

2 allele pairs (4 total) at different foci

Question 9

What are the components of Hb and their associated pathologies

Answer 9

Hb = heme (protoporphyrin + Fe) + globin
protoporphyrin: sideroblastic
Fe: iron-deficiency
globin: thalassemias

Question 10

α-thalassemia

mutations may occur on different alleles, using this terminology

Answer 10

cis: occurs on same chromosome
* worse for offspring if they inherit this one
trans: occurs on opposite chromosome

Question 11

α-thalassemia
1 mutation
2 mutations
3 mutations
4 mutations

Answer 11

1: silent
2: not severe anemia
3: HbH disease (made of β4) because very little α-chain
4: hydrops, formation of γ4

Question 12

Iron deficiency anemia

microcytic or what?

Answer 12

begins normocytic
becomes microcytic because cells continue to divide
the cells want to concentrate their Hb to make themselves nice and pink
but their cytoplasm gets less with each division
–> microcytic

Question 13

Labs in iron deficiency anemia
iron
TIBC
transferrin
ferritin

Answer 13

iron: low
TIBC: high
transferrin: high
ferritin: low

Question 14

What do these labs measure?
iron
TIBC
transferrin
ferritin

Answer 14

iron: serum iron
TIBC: binding sites available on transferrin
transferrin: amt of transferrin protein in serum
ferritin: measures iron stores in macrophages in liver, BM, etc

Question 15

FEP (free erythrocyte protoporphyrin) in iron-deficiency anemia

Answer 15

high

because there is excess protoporphyrin, relative deficiency compared to iron

Question 16

What is the basic defect is sideroblastic anemia

Answer 16

iron overloaded state
because of defect in δALA-synthase protein
iron builds up in mitochondria around nucleus

Question 17

How do you stain for sideroblastic anemia

Answer 17

Prussian blue stain

Question 18

Inheritance pattern of genetic sideroblastic anemia

Answer 18

X-linked

Question 19

Etiologies of sideroblastic anemia

Answer 19

genetic
lead
alcohol (most common)
B6 deficiency (commonly from isoniazid)
Cu deficiency

Question 20

Iron status in sideroblastic anemia

Answer 20

iron overload

Question 21

Labs in sideroblastic anemia
iron
TIBC
ferritin

Answer 21

iron: high
TIBC: normal to low
ferritin: high (high iron storage)