Hematopoesis, erythrocytes, and Regenerative Anemia Flashcards
What would bone marrow look like in a young animal? Old animal?
Hypercellular
Hypocellular
Where does hematopoesis occur in domestic animals? Birds?
Hematopoetic spaces
Venous sinuses
What cells regulate the release of cells into sinuses?
Reticular cells
What are the first two committed stem cells in the production of erythrocytes?
BFU-E
CFU-E
Where is erythropoetin produced and what stimulates it?
Produced in the kidneys of adults
Stimulated by hypoxia
What factors inhibit erythropoesis?
TNFalpha, IL-6, TGF-Beta, Estrogen
What stage of the RBC does hemoglobin synthesis start?
Early rubricyte
What is the first cell to be identified as part of RBC lineage?
Rubriblast
What stage is the nucleus extruded?
Metarubricyte
What stage is released from bone marrow?
Reticulocyte
At what stage of RBC creation does cell division stop?
Late rubricyte
What species has the longest average erythrocyte life span? Shortest?
Cattle = 160 d. Birds = 35 d.
What is different about cats’ spleens?
They have a closed splenic circulation; makes them less efficient at RBC removal and they lack large RBC reserve pools
What is MCV and what does it mean?
Mean corpuscular volume; it is the volume per average erythrocyte
What is the terminology for describing MCV?
Normocytic, Macrocytic (increased), Microcytic (decreased)
What are causes of microcytosis?
Iron deficiency, liver dz, anemia of inflammatory dz
What causes macrocytosis?
Reticulocytosis (BIG), breed association, agglutination
What is MCHC and what does it mean?
Mean Cell Hemoglobin Concentration; average hemoglobin concentration per average erythrocyte
What are the terms for describing MCHC?
Normochromic, Hyperchromic (increased), Hypochromic (decreased)
What are some causes of hyperchromia?
Hemolysis, RBC shape changes, lipemia
What are some causes of hypochromia?
Reticulocytosis and iron deficiency
What is anisocytosis?
The index of the variability in erythrocyte size in a sample
What are reticulocytes? What are some facts about them?
They are immature, non-nucleated RBCs
They are larger and bluer than RBCs
Reticulocytosis is an important indicator of what?
accelerated erythropoesis
What are the two types of reticulocytes in cats?
Punctate: not considered a sign of regeneration
Aggregate: counted in reticulocyte count
T/F Reticulocytes are released by every species during a regenerative anemia
FALSE; horses do not reliably release reticulocytes during regenerative anemia
What is the reticulocyte percentage? What is the CRP?
% of RBCs that are reticulocytes
CRP: % estimate of RP if the patient were not anemic
How do you figure the CRP? What are the baselines and how do you interpret them?
RP X (Patient's HCT / Average HCT) HCT Average: Dog 45%, Cat 40%, Cow 35% Dog: >1.0 = regenerative Cat and Cow: >.4 = regenerative
Anemia is classified as what?
Decrease in RBC count, hemoglobin, or HCt
Caused by increased RBC loss, Increased RBC destruction, or decreased production
How do we assess regeneration of anemia in cats and dogs?
If reticulocytes are present (regenerative) or absent (non-regenerative)
What is different about assessing anemia in ruminants?
Nucleated RBCs can also be used to determine regeneration
In dogs and cats, what is the difference between appropriate and inappropriate rubricytosis?
Appropriate: rubricytes with reticulocytes
Inappropriate: nRBCs in circulation without reticulocytosis
What are the two types of hemolysis and what are the differences?
Intravascular: erythrocyte destruction occurs within blood vessels
Extravascular: accelerated phagocytosis of RBCs
Where does bilirubin come from?
Degregation of Hgb
What are some causes of hemolytic anemia caused by intravascular hemolysis?
Complement mediated lysis, physical injury, oxidative injury, osmotic lysis, metabolic
What are some common oxidative agents in vet med?
Onions, garlic, zinc, copper, acetaminophen, vitamins K1 and K3, hydrogen peroxide
What are Heinz Bodies?
Aggregates of denatured hemoglobin from oxidative damage
What are ghost cells?
Pathologic finding of intravascular hemolysis
Artifact from traumatic blood draw
What are some causes of hemolytic anemia via extravascular hemolysis?
Immune mediated, decreased RBC deformability, reduced glycolysis, or increased macrophage phagocytic activity
What’s the most common cause of hemolytic anemia in dogs?
Immune hemolytic anemia
What are spherocytes?
Left over RBCs that have been partially phagocytosed
What causes RBCs to agglutinate?
Anti-erythrocyte IgM or VERY high anti-erythrocyte IgG
What is the saline dispersion test?
When your agglutinated RBCs do not disperse when saline is added
What is evidence for an IHA diagnosis?
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)
