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howell-jolly bodies (micronuclei) =
normal in which animals?

dark dots of micronuclei seen on RBC

normal in horses and cats bc their spleen doesn't have a very good pitting function bc they are full of muscle compared to our spleens which have many reticular things that pick out howell jolly bodies


what things cause howell-jolly bodies?

- regenerative anemias
- splenectomy
- glucocorticoids (immunosuppressants - if you suppress macrophages, they wont be good at kicking out micronuclei)
- oxidative damage (onions and garlic/baby food)
- zinc toxicity
- acetaminophen toxicity


what should you do when looking for heinz bodies?

do a new metylene blue stain
- and look at MCHC: heinz bodies are 1 of only 3 things that can artificially elevate it.


EXAM Q: what 3 disease processes in cats will increase heinz body formation?

1. diabetes
2. lymphoma
3. hyperthyroidism


can you see heinz bodies in a normal blood film?

no! you may see howell-jolly bodies (micronuclei) but you can only see heinz bodies on new methylene blue stains


EXAM Q: what causes a really robust regenerative anemia in large animals?

basophilic stippling


are heinz bodies an issue in large animals?

not really - they will be selenium deficient and be exhibiting neuromuscular issues before you start seeing heinz bodies so you will have bigger fish to fry than heinz bodies


things that cause eccentrocytes (Hgb only on part of RBC)

- oxidant injury
- acetaminophen toxicity
- red maple toxicity in horses


basophilic stippling =

aggregates of ribosomes on RBCs, they will be different sizes and be more than 15

- hardly see them with Pb toxicity in small animal


when do you see basophilic stippling in small animal?

basophilic stippling + no anemia (aberrant metarubriocytosis - absence of polychromasia and anemia) = Pb toxicity


siderotic inclusions =

iron laden in RBC. it will look like basophilic stippling but these inclusions will be focal and kind of clump together


what is the leading cause of hemolytic anemia?

infectious agents of RBCs


what agent is not pathogenic, is a protozoal agent and usually found in ruminants?

Theileria spp. (they can still cause hemolysis so you dont want them floating around)


how do fevers work? - cytauxzoon felis and cats example

fever is caused by inflammation.
- macrophages react to inflammation by producing Interleukin-1
- Ilk-1 resets hypothalamus to a higher body temperature by making you do heat generating activities to keep bacteria from replicating
- once fever breaks, animals will be hypothermic


why are animals hypothermic when emerging from a fever?

- body lyses RBCs which causes you to become anemic
- anemia causes poor perfusion which causes you to go into hypervolemic shock
- hypervolemic shock causes you to shunt the blood you have left (after all lysing) to vital areas like heart and brain which causes your temperature to drop.


hemotrophic =

meaning they are everywhere


how are mycoplasma pathogenic?

by literally sitting on the cell and sucking out nutrients bc they dont have their own cell wall


EXAM Q: what does white/pale gums mean?

poor peripheral perfusion!!

(NOT anemia)


extravascular hemolysis

lysis of RBCs at an increased rate due to an infectious agent not within vasculature but within the spleen. you are destroying your RBCs earlier than you should, buts its ok bc you will recycle all the materials like iron, protein, etc but it is still a form of anemia just has a better prognosis


EXAM Q: which stain is best to see distemper inclusions?


distemper inclusions infect RBCs when they are rubrioblasts - when they are in the bone marrow and have a nucleus


what are clinical signs of anemia due to?

decreased blood supply to tissues!


clinical signs of anemia are influenced by:

are due to decreased O2 supply to tissues
- rate of decrease in RBC number
- severity of decrease in RBC number
- cardiopulmonary function
- age and activity of animal
- cause of anemia


clinical signs of anemia

- weakness
- lethargy
- poor peripheral perfusion (pale mm)
- cardiovascular: tachycardia (bc its trying to get less blood to places faster), poor pulse quality, systolic murmur
- pulmonary (tachypnea, dyspnea)


when do RBCs stop dividing and just start differentiating?



do cats have punctate retics, aggregate retics, or both?

Both! they are the only species to have punctate retics and aggregate retics. all other animals have only aggregate retics.


do we care about punctate retics or aggregate retics?

aggregate bc they live in circulation for only a day while punctates last 10 days.


what is the difference in appearance of aggregate retics vs punctate retics?

aggregate retics have little bands or blobs of RNA while punctate retics have little basophilic stippling of RNA within the RBC (in new methylene blue)

--> only aggregates appear to be polychromatophilic with wright giemsa stain. punctate retics look like normal mature RBCs with wright giemsa stain


relative reticulocyte count =

the percentage of all RBCs that are reticulocytes.

- a normal animal has less than 1% retics circulating around
- large animals dont release any retics so their % should be zero
- remember you are basing this % off your PCV so you really want absolute numbers


EXAM Q: do horses release retics?



Interpretation of retic concentration

when anemia is present, a greater degree of release of retics from the marrow is expected if the marrow is able to respond to the anemia properly