Exam 1: Lecture 4

Question 0

what things cause howell-jolly bodies?

Answer 0

• 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

Question 1

howell-jolly bodies (micronuclei) =

normal in which animals?

Answer 1

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

Question 2

what should you do when looking for heinz bodies?

Answer 2

do a new metylene blue stain

- and look at MCHC: heinz bodies are 1 of only 3 things that can artificially elevate it.

Question 3

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

Answer 3

1. diabetes
2. lymphoma
3. hyperthyroidism

Question 4

can you see heinz bodies in a normal blood film?

Answer 4

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

Question 5

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

Answer 5

basophilic stippling

Question 6

are heinz bodies an issue in large animals?

Answer 6

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

Question 7

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

Answer 7

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

Question 8

basophilic stippling =

Answer 8

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

• hardly see them with Pb toxicity in small animal

Question 9

when do you see basophilic stippling in small animal?

Answer 9

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

Question 10

siderotic inclusions =

Answer 10

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

Question 11

what is the leading cause of hemolytic anemia?

Answer 11

infectious agents of RBCs

Question 12

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

Answer 12

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

Question 13

how do fevers work? - cytauxzoon felis and cats example

Answer 13

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

Question 14

why are animals hypothermic when emerging from a fever?

Answer 14

• 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.

Question 15

hemotrophic =

Answer 15

meaning they are everywhere

Question 16

how are mycoplasma pathogenic?

Answer 16

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

Question 17

EXAM Q: what does white/pale gums mean?

Answer 17

poor peripheral perfusion!!

NOT anemia

Question 18

extravascular hemolysis

Answer 18

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

Question 19

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

Answer 19

dif-quick!!

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

Question 20

what are clinical signs of anemia due to?

Answer 20

decreased blood supply to tissues!

Question 21

clinical signs of anemia are influenced by:

Answer 21

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

Question 22

clinical signs of anemia

Answer 22

• 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)

Question 23

when do RBCs stop dividing and just start differentiating?

Answer 23

metarubriocyte

Question 24

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

Answer 24

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

Question 25

do we care about punctate retics or aggregate retics?

Answer 25

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

Question 26

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

Answer 26

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

Question 27

relative reticulocyte count =

Answer 27

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

Question 28

EXAM Q: do horses release retics?

Answer 28

NO!!!

Question 29

Interpretation of retic concentration

Answer 29

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

Question 30

reticulocytosis =

Answer 30

increased numbers of reticulocytes means you have a regenerative anemia - bone marrow is not a problem because its working

Question 31

what does regenerative response mean?

Answer 31

it means the anemia was caused by hemorrhage or increased RBC destruction. NOT by decreased RBC production

Question 32

how many days does it take bone marrow to respond to anemia? what is the significance of this?

Answer 32

3 - 4 days. if you catch regenerative anemia in the very beginning before the bone marrow has had a chance to respond, it may look like non-regenerative anemia which means the bone marrow could be a problem. <-- tricky window to be in

Question 33

what is the average HCT (=PCV) for a dog?

Answer 33

45%

Question 34

what is the average HCT (=PCV) for a cat?

Answer 34

37%

Question 35

corrected reticulocyte count formula (know the numbers!!)

Answer 35

raw reticulocyte count (%) x (HCT of patient /mean HCT of species) =

Question 36

absolute reticulocyte count

Answer 36

take percentage x RBC mass = allows you to focus on absolute numbers