11.5: Anemia I Flashcards Preview

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Flashcards in 11.5: Anemia I Deck (57):
1

What is a pluripotent stem cell?

Precursor of all blood cell lines: RBC, WBC, platelet

2

What is hematopoiesis?

- Series of events in which pluripotent stem cells mature into functional blood cells
- Occurs in marrow

3

RBC characteristics?

- Anucleate
- Bi concave
- Make up majority of blood cells

4

What is blood smear?

- Allows visualization of formed blood elements
- Drop of blood on glass then stained

5

How do you see if there is issue with hematopoiesis?

Bone marrow aspirate and biopsy

6

What is a reticulocyte?

- First stage or RBC released from marrow into periphary
- Cytoplasm may be blueish bind from residual RNA

7

Life span of RBC?

120 Days

8

What is the structure of RBC membrane? How is it different from other cells?

***Membrane skeleton controlling bi concave shape and cell malleability: Allows for microcirculation transit
- Otherwise is phospholipid bilayer with membrane proteins, glycolipids and cholesterol just like other cells

9

What is hemoglobin?

- Functional protein in RBC allowing for O2 transport

10

2 Biosynthetic pathways involved in hemoglobin synthesis?

1. Synthesis of HEME
2. Synthesis of globin chains

11

What is heme?

- 4 pyrrole groups joined in a ring
- Ferrous iron is incorporated in center

12

What are globin chains?

- 150 aa protein with heme binding site
- 2 Globin dimers form hemoglobin
- Hemoglobin A comprises 95% of globin in adults

13

What is hemoglobin A?

- Makes of 95% of adult hemoglobin
- Composed of 2 alpha and 2 beta chains

14

How are aging RBCs removed?

- Mononuclear phagocytes in spleen responsible for removal of aged RBCs
- Heme is divided into iron which is recycled, and porphyrin rings: removed as bilirubin
- Globin is dismantled into amino acids

15

What are porphyrin rings?

- Byproduct of heme degradation
- Eliminated as bilirubin

16

Term for accelerated RBC destruction?

Hemolysis

17

What is anemia?

- Reduced oxygen carrying capacity of the blood
- Reduction in red cell mass

18

3 Classes of anemia?

1. Blood loss
2. Hemolytic: increased rate of destruction
3. Diminished production

19

Intrinsic factors leading to increased hemolysis?

1. Spherocytosis
2. G6PD deficiency
3. Sickle Cell anemia
4. Thalassemia
5. PNH (Acquired)

20

3 types of disturbances in differentiation?

1. Iron deficiency anemia
2. Megaloblastic anemia: B12/folate
3. Anemia of chronic disease

21

What is MCV?

"Mean cell volume"
- Reading from CBC

22

What is MCH?

"Mean cell Hemoglobin"
- Reading from CBC

23

What is MCHC?

"Mean cell Hemoglobin concentration"
- Reading from CBC

24

What is RDW?

"Red cell distribution width"
- Measures anisocytosis
- Variation in RBC volume

25

What is anisocytosis?

Variation in RBC size

26

Examples of MICROcytic anemia?

1. Iron deficiency
2. Thalassemias
3. Anemia of chronic disease

27

Examples of MACROcytic anemia?

1. Megaloblastic anemia: B12 / Folate deficiency

28

Characteristics of hemolytic anemias?

1. Shortened RBC lifespan
2. Accumulation of products of RBC metabolism
3. Increase in erythropoiesis from bone marrow

29

Where does extravascular hemolysis occur?

Spleen

30

Where does intravascular anemia occur and what does in cause?

Occurs in vascular compartment causing:
1. Hemoglobinemia
2. Hemoglobinuria
3. Hemosiderinuria: byproduct of iron metabolism

31

What happens to free hemoglobin in the blood?

- Binds to haptoglobin and is removed by liver
- Low haptoglobin means hemolytic anemia

32

What does low haptoglobin mean?

- Hemolytic anemia
- It is binding the hemoglobin to remove it from serum

33

What is extravascular hemolysis?

- Accelerated destruction of RBCs in spleen by macs
- More common than intravascular
- Don't see same products in serum
- Hyperactive reticular system leads to splenomegaly

34

What is hereditary spherocytosis?

- Intrinsic deficiency in RBC spectrin or ankyrin
- Spheroid RBCs, less malleable
- More vulnerable to splenic destruction/sequestration
- Autosomal dominant

35

What is spectrin?

- Main protein in membrane skeleton of RBC
- Deficiency leads to spherocytosis

36

What is ankyrin?

- Protein that anchors spektrin to membrane proteins
- Deficient in autosomal dominant Spherocytosis
- Recessive is spectrin deficiency

37

Pathophysiology of spherocytosis?

- Decreased interaction w/ skeleton and lipids layer
- Reduced membrane stability and loss of fragments
- Decreased surface are to volume ratio causing spherical shape

38

What does biconcave shape of RBC allow for?

- Deformation allowing it to squeeze through tight spaces in spleen and other areas
- If you are spherical, takes longer to get through spleen and macs eat you

39

What can improve spherocytosis?

- Splenectomy
- Prevents destruction of RBCs in spleen
- Still have disease by symptoms are better

40

What are RBCs w/o central pallor in smear indicative of?

Spherocytosis

41

Clinical findings in spherocytosis?

1. Jaundice
2. Anemia
3. Splenomegaly
4. Increased osmotic fragility
5. Increased MCHC

42

What are anemia, jaundice, and splenomegaly consistent with?

Spherocytosis

43

What is Aplastic crisis?

- Occurs in hemolytic anemia
- Bone marrow ramps up and is maxed out
- If infection occurs, marrow cannot respond with WBCs

44

What is increased MCHC characteristic of?

Spherocytosis

45

How is G6PD deficiency inherited?

- X linked
- Higher incidence in males than females

46

When does G6PD deficiency manifest?

- Usually there are no symptoms
- When there is oxidative stress on RBC from stress or infection

47

What is the glutathione system?

- Manner in which RBCs deal with oxidative stress
- Glutathione is oxidized by stress to protect RBC
- NADPH reduces Glutathione so it can be used again becoming NADP in process
- G6PD responsible for converting back into NADPH

48

How does oxidative stress damage RBC?

- H2O2 oxidizes sulfhydryl groups of globin chains
- Hemoglobin denatures and precipitates forming Heinz bodies
- Heinz bodies attach to RBC membrane decreasing maleability

49

What are Heinz bodies?

- Denatured hemoglobin from oxidative stress
- Bind to RBC decreasing maleability
- Causes intravascular hemolysis
- Macs also bit off Heinz bodies leading to spherocytes

50

Clinical course of G6PD deficiency?

- Intravascular hemolysis
- Hemoglobinemia
- Hemoglobinuria
- Decreased hematocrit
- Bone marrow produces more RBCs to compensate

51

What is Sickle Cell disease?

- Structurally abnormal hemoglobin synthesis
- Most common form of familial hemolytic anemia
- Defective HbS
- You must be homozygous to show symptoms

52

What is the most common form of hemolytic anemia?

Sickle cell Disease

53

What is HbS?

- Responsible for sickle cell trait

54

Pathophys of sickle cell?

- Point mutation of valine for glutamic acid in B globin
- Forms HbS molecules that aggregate and polymerize
- Red cell distorts into sickle shape

55

3 things sickling of cells dependant on?

1. Fall in PH
2. Amount of HbS
3. High MCHC

56

Clinical consequences of sickling?

1. Hemolytic anemia
2. Occlusion of small vessels
3. Splenomegaly in kids
4. Hypoxic damage to spleen leading to fibrosis
5. Vaso Occlusive / painful crises
6. Aplastic crises
7. Increased susceptibility to infection
8. Ischemic damage from occlusion

57

What happens in sickle cell trait?

- Usually not clinical appearance