Pathology of Anemia II Flashcards Preview

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Flashcards in Pathology of Anemia II Deck (38):
1

What is thalassemia?

Group of genetic disorders characterized by the lack, or decreased synthesis, of either alpha or beta-globin chains of hemoglobin A

2

What is alpha thalassemia?

– alpha-thalassemia􏰁 - globin chain synthesis is reduced

3

What is beta thalassemia?

– beta-thalassemia - 􏰂-globin chain synthesis is absent or reduced

4

What are some consequences of thalassemia?

– low intracellular hemoglobin (hypochromia)
– relative excess of other chain

5

What are the 4 types of alpha thalassemia?

- Silent carrier 􏰁-a/aa
- α-thalassemia trait
--/aa􏰁 (Asian)
-􏰁a/-a􏰃􏰁 (black African)
- HbH disease --/-a
- Hydropsfetalis --/--

6

ß˚􏰂􏰄-thalassemia

It refers to lack of ß􏰂-globin expression

7

ß+-thalassemia

It refers to decreased ß-globin expression

8

How does ß-thalassemia cause anemia?

– reduced synthesis of 􏰂-globin leading to inadequate HbA formation
– hemolytic component of the disease due to relative excess of 􏰁-globin chains

9

Thalassemia Major

Clinical term to describe severe disease, reliance on transfusions

10

Thalassemia Minor

Clinical term to describe patients with asymptomatic, mild or absent anemia, some RBC abnormalities

11

What can be seen in the skull of ß-thalassemia patients?

Crew cut - expansion of marrow in the skull trying to
produce RBCs in beta thalassemia major

12

What do target cells in the smear indicate?

ß-thalassmia Minor

13

What is the only acquired defect in the RBC membrane?

Paroxysmal Nocturnal Hemoglobinuria

14

What is the change in Paroxysmal Nocturnal Hemoglobinuria?

Stem cell disorder that results from a mutation in the phosphatidylinositol glycan A (PIGA) gene which results in a deficiency of the GPI anchor

15

What are some important GPI proteins and what are they functions?

– CD55 (decay-accelerating factor)
– CD59 (membrane inhibitor of reactive lysis)
– C8 binding protein

These proteins are involved in inactivating or the complement pathway - leads to unchecked activation and RBC destruction

16

How can mechanical trauma cause anemia?

- Anemia due to prosthetic cardiac valves that destroy RBCs
- Narrowing of small vessels and fibrin deposition (microangiopathic hemolytic anemia)

17

What is seen on smear with mechanical trauma?

Shistocytes

18

What are often causes of iron deficiency anemia?

-􏰀 Some disorders result in malabsorption of iron (sprue, gastrectomy)
􏰀- Adequate diet under usual circumstances may not meet demand for iron during pregnancy and infancy
􏰀- Most important cause of iron deficiency in the Western world is chronic blood loss

19

What happens to total iron binding capacity (TIBC) in iron deficiency anemia?

Increases

20

What happens to the size of cells in iron deficiency anemia?

They become small - microcytic

21

What is seen on smear with iron deficiency anemia?

Central pallor spreads to almost the entire cell

22

What is megaloblastic anemia?

􏰀Disturbances of proliferation and maturation of erythroblasts due to defective DNA synthesis

23

What are the 2 types of megaloblastic anemia?

- Vitamin B12
- Folate

24

What are the functions of vitamin B12 and folate?

Both B12 and folate are coenzymes in the DNA biosynthetic pathway

25

What happens to the size of cells in megaloblastic anemia?

Enlargement of proliferating cells, particularly in erythroid precursors, is seen - macrocytic

26

What are enlarged RBC precursors and enlarged RBCs called?

– enlarged red cell precursors are called megaloblasts
– enlarged red cells are called macrocytes or macro-ovalocytes

27

Why is there enlargement in megaloblastic anemia?

Impairment of DNA synthesis underlies enlargement. Cellular nuclei are immature and cytoplasm is fully mature: nuclear- cytoplasmic asynchrony.

28

What are some causes of vitamin B12 deficiency?

– Inadequate diet (vegetarians at increased risk)
– Increased requirements
– Impaired absorption (Intrinsic Factor deficiency)

29

What is pernicious anemia?

“Pernicious anemia” applies to vitamin B12 deficiency secondary to atrophic gastritis with failure of production of intrinsic factor (IF)

30

What are the clinical findings with vitamin B12 deficiency?

Clinical findings found mainly in alimentary tract, blood, bone marrow, and in CNS

31

What can be seen on a smear in megaloblastic anemia?

Hypersegmented neutrophil

32

What are the clinical findings of folate deficiency?

Similar to vitamin B12 megaloblastic anemia, but there are no CNS effects

33

How does treatment of vitamin B12 deficiency with folate work out?

Prompt response - folic acid will improve B12 deficiency
as well but does NOT treat the CNS abnormalities

34

What is anemia of chronic disease?

Caused by high levels of plasma hepcidin that blocks transfer of iron from macrophages to erythroid precursors

35

Is anemia of chronic disease macrocytic or microcytic?

Microcytic with low serum iron

36

What is the total iron binding capacity in anemia of chronic disease?

Decreased total iron binding capacity

37

Aplastic Anemia

Failure or suppression of stem cells leads to a hypocellular marrow

38

What is the bone marrow typically like in aplastic anemia?

Bone marrow typically is hypocellular with increased fat and small foci of lymphocytes and plasma cells

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