Hematopoesis, erythrocytes, and Regenerative Anemia

Question 1

What would bone marrow look like in a young animal? Old animal?

Answer 1

Hypercellular

Hypocellular

Question 2

Where does hematopoesis occur in domestic animals? Birds?

Answer 2

Hematopoetic spaces

Venous sinuses

Question 3

What cells regulate the release of cells into sinuses?

Answer 3

Reticular cells

Question 4

What are the first two committed stem cells in the production of erythrocytes?

Answer 4

BFU-E

CFU-E

Question 5

Where is erythropoetin produced and what stimulates it?

Answer 5

Produced in the kidneys of adults

Stimulated by hypoxia

Question 6

What factors inhibit erythropoesis?

Answer 6

TNFalpha, IL-6, TGF-Beta, Estrogen

Question 7

What stage of the RBC does hemoglobin synthesis start?

Answer 7

Early rubricyte

Question 8

What is the first cell to be identified as part of RBC lineage?

Answer 8

Rubriblast

Question 9

What stage is the nucleus extruded?

Answer 9

Metarubricyte

Question 10

What stage is released from bone marrow?

Answer 10

Reticulocyte

Question 11

At what stage of RBC creation does cell division stop?

Answer 11

Late rubricyte

Question 12

What species has the longest average erythrocyte life span? Shortest?

Answer 12

Cattle = 160 d.
Birds = 35 d.

Question 13

What is different about cats’ spleens?

Answer 13

They have a closed splenic circulation; makes them less efficient at RBC removal and they lack large RBC reserve pools

Question 14

What is MCV and what does it mean?

Answer 14

Mean corpuscular volume; it is the volume per average erythrocyte

Question 15

What is the terminology for describing MCV?

Answer 15

Normocytic, Macrocytic (increased), Microcytic (decreased)

Question 16

What are causes of microcytosis?

Answer 16

Iron deficiency, liver dz, anemia of inflammatory dz

Question 17

What causes macrocytosis?

Answer 17

Reticulocytosis (BIG), breed association, agglutination

Question 18

What is MCHC and what does it mean?

Answer 18

Mean Cell Hemoglobin Concentration; average hemoglobin concentration per average erythrocyte

Question 19

What are the terms for describing MCHC?

Answer 19

Normochromic, Hyperchromic (increased), Hypochromic (decreased)

Question 20

What are some causes of hyperchromia?

Answer 20

Hemolysis, RBC shape changes, lipemia

Question 21

What are some causes of hypochromia?

Answer 21

Reticulocytosis and iron deficiency

Question 22

What is anisocytosis?

Answer 22

The index of the variability in erythrocyte size in a sample

Question 23

What are reticulocytes? What are some facts about them?

Answer 23

They are immature, non-nucleated RBCs

They are larger and bluer than RBCs

Question 24

Reticulocytosis is an important indicator of what?

Answer 24

accelerated erythropoesis

Question 25

What are the two types of reticulocytes in cats?

Answer 25

Punctate: not considered a sign of regeneration Aggregate: counted in reticulocyte count

Question 26

T/F Reticulocytes are released by every species during a regenerative anemia

Answer 26

FALSE; horses do not reliably release reticulocytes during regenerative anemia

Question 27

What is the reticulocyte percentage? What is the CRP?

Answer 27

% of RBCs that are reticulocytes | CRP: % estimate of RP if the patient were not anemic

Question 28

How do you figure the CRP? What are the baselines and how do you interpret them?

Answer 28

``` RP X (Patient's HCT / Average HCT) HCT Average: Dog 45%, Cat 40%, Cow 35% Dog: >1.0 = regenerative Cat and Cow: >.4 = regenerative ```

Question 29

Anemia is classified as what?

Answer 29

Decrease in RBC count, hemoglobin, or HCt | Caused by increased RBC loss, Increased RBC destruction, or decreased production

Question 30

How do we assess regeneration of anemia in cats and dogs?

Answer 30

If reticulocytes are present (regenerative) or absent (non-regenerative)

Question 31

What is different about assessing anemia in ruminants?

Answer 31

Nucleated RBCs can also be used to determine regeneration

Question 32

In dogs and cats, what is the difference between appropriate and inappropriate rubricytosis?

Answer 32

Appropriate: rubricytes with reticulocytes Inappropriate: nRBCs in circulation without reticulocytosis

Question 33

What are the two types of hemolysis and what are the differences?

Answer 33

Intravascular: erythrocyte destruction occurs within blood vessels Extravascular: accelerated phagocytosis of RBCs

Question 34

Where does bilirubin come from?

Answer 34

Degregation of Hgb

Question 35

What are some causes of hemolytic anemia caused by intravascular hemolysis?

Answer 35

Complement mediated lysis, physical injury, oxidative injury, osmotic lysis, metabolic

Question 36

What are some common oxidative agents in vet med?

Answer 36

Onions, garlic, zinc, copper, acetaminophen, vitamins K1 and K3, hydrogen peroxide

Question 37

What are Heinz Bodies?

Answer 37

Aggregates of denatured hemoglobin from oxidative damage

Question 38

What are ghost cells?

Answer 38

Pathologic finding of intravascular hemolysis | Artifact from traumatic blood draw

Question 39

What are some causes of hemolytic anemia via extravascular hemolysis?

Answer 39

Immune mediated, decreased RBC deformability, reduced glycolysis, or increased macrophage phagocytic activity

Question 40

What's the most common cause of hemolytic anemia in dogs?

Answer 40

Immune hemolytic anemia

Question 41

What are spherocytes?

Answer 41

Left over RBCs that have been partially phagocytosed

Question 42

What causes RBCs to agglutinate?

Answer 42

Anti-erythrocyte IgM or VERY high anti-erythrocyte IgG

Question 43

What is the saline dispersion test?

Answer 43

When your agglutinated RBCs do not disperse when saline is added

Question 44

What is evidence for an IHA diagnosis?

Answer 44

Regenerative anemia Spherocytes on smear Agglutination on smear Saline dispersion test; agglutination persists Inflammatory leukogram Positive Coombs test (Only run in saline dispersion is negative)