RBC Infectious Agents and Reticulocytes Flashcards Preview

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Flashcards in RBC Infectious Agents and Reticulocytes Deck (25)
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1
Q

What are these and in what species are low numbers of them normal?

A

Howell-Jolly bodies

normal in cats and horses

increased in regenerative anemia, splenectomy, glucocorticoid administration

2
Q

What are these and seeing what % of them in a cat blood smear is normal? What can they be caused by otherwise?

A

Heinz bodies - up to 5% normal in cats; increased with diabetes, lymphoma, and hyperthyroidism

oxidative damage - onion and garlic ingestion

other: splenectomy (dogs), propylene glycol in soft food (cats), zinc toxicity (dogs), RX (acetaminophen, methylene blue, methionine, phenazopyridine, menadione), napthalene/moth balls, propofol anesthesia (cats)

SKUNK MUSK

3
Q

In what circumstances would you see heinz bodies in large animals?

A

After eating: wild/domestic onions, kale and other brassica species (ruminants), red maple leaves (horses and alpacas), copper toxicity (sheep and goats), lush winter rye (florida cattle

selenium deficient cattle on St. Augustine grass

post-parturient New Zealand cattle on perennial ryegrass

phenothiazine in horses

4
Q

What are these and what RBC morphology are they similar to in cause?

A

Eccentrocytes - similar to Heinz Bodies because also caused by oxidant injury

Causes: acetaminophen, onions, garlic, propofol, viamin K, antagonist rodenticides in dogs, red maple toxicity in horses, IV hydrogen peroxide in a cow, enzyme deficiencies in horses

5
Q

Seeing this - is it a good or bad sign if you see it in an anemic cow?

A

Good - means anemia is regenerative in ruminants

it is basophilic stippling - aggregates of ribosomes and polyribosomes

*can indicate lead toxicity

6
Q

What are these? What do they indicate?

A

siderotic inclusions - focal stippling

may involve iron-laden mitochondria and/or autophagic vacuoles

can indicate zinc toxicity

chloramphenicol and hydroxyzine therapy

hemolytic anemia

dyserythropoiesis

pyridoxine deficiency

7
Q

Name some infectious agents of erythrocytes.

A

Protozoal organisms: babesia, theileria, cytauxzoon

Rickettsial : anaplasma

Mycoplasmal

Bacterial: bartonella

Viral: distemper

8
Q

“spiderman” cells = what disease?

A

babesia

9
Q

This parasite achieves schizogony in what blood cell?

A

lymphocytes

this parasite = theileria

species in USA ruminants are usually non-pathogenic

10
Q

name this parasite!

A

cytauxzoon felis

11
Q

name this parasite! hint: can be transmitted by ticks

A

anaplasma

12
Q

Name this infectious agent. Hint: this slide is from a cat.

A

Mycoplasma

13
Q

Image is from the same infectious agent with two different stains. Bottom stain is Diff-Quik. What is the infectious agent?

A

Distemper virus

14
Q

What is anemia and its clinical signs?

A

low circulating RBCs for the species, breed, gender, and age of animal

a sign of underlying disease, not a disease

clinical signs - due to decreased delivery of O2 to tissues, weakness, lethargy, poor peripheral perfusion (pale MM, sclera), tachycardia, poor pulse quality, systolic murmur, tachypnea, dyspnea

15
Q

Seeing marrow precursor cells in a blood smear indicates what?

A

regenerative anemia

16
Q

How long does reticulocyte maturation take in dogs?

A

24-48 hours

17
Q

What is the difference between the cells marked “A” and the cells marked “P” in the slide?

A

aggregate reticulocytes vs. punctate reticulocytes - punctate are older in the development process, distinguishable from normal RBCs using Wright’s Giemsa stain; only aggregate retics look polychromatophilic with Wright’s Giemsa stain

18
Q

These two slides show two different stains of what RBC developmental stage?

A

reticulocytes (in dog blood)

two stains are: wright-giemsa on left, new methylene blue on right

19
Q

How long does it take reticulocytes to mature in dogs? cats?

A

dogs - one day

cats - aggregate to punctate in one day, punctate to mature in a week or more

20
Q

What is a relative reticulocyte count and how can you use it?

A

percentage of all erythrocytes that are reticulocytes

dogs: less than 1% = healthy, nonanemic
cats: 0-0.5% aggregate and 1 to 10% punctate reticulocytes = healthy nonanemic

RUMINANTS AND HORSES DO NOT NORMALLY HAVE RETICULOCYTES IN BLOOD

21
Q

Why do you not see reticulocytes in equine blood smears?

A

retics almost never released into circulation - maturation confined to the bone marrow

22
Q

If anemia is present and your reticulocyte concentration is 5000 cells/microliter… are you concerned?

A

Yes -

1-10,000 = nonregenerative to very poorly regenerative

10,000-60,000 -nonregenerative to poorly regenerative

60k-200k - mildly to moderately regenerative

200k-500k - very regenerative

23
Q

What does the presence of a regenerative response tell you about the cause of an anemia?

A

anemia caused by hemorrhage or increased erythrocyte destruction, not decreased erythrocyte production

24
Q

How many days does it take for an animal to increase its RBC synthesis and release reticulocytes from bone marrow?

A

3-4 days

25
Q

How does the degree of anemia affect the reticulocyte percentage?

A

Less blood cells total makes fewer reticulocytes seem more important

ie. 1 reticulocyte out of 10 blood cells is 10% but 1 reticulocyte out of 4 blood cells is 25%