RBC Infectious Agents and Reticulocytes Flashcards
What are these and in what species are low numbers of them normal?
Howell-Jolly bodies
normal in cats and horses
increased in regenerative anemia, splenectomy, glucocorticoid administration
What are these and seeing what % of them in a cat blood smear is normal? What can they be caused by otherwise?
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
In what circumstances would you see heinz bodies in large animals?
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
What are these and what RBC morphology are they similar to in cause?
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
Seeing this - is it a good or bad sign if you see it in an anemic cow?
Good - means anemia is regenerative in ruminants
it is basophilic stippling - aggregates of ribosomes and polyribosomes
*can indicate lead toxicity
What are these? What do they indicate?
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
Name some infectious agents of erythrocytes.
Protozoal organisms: babesia, theileria, cytauxzoon
Rickettsial : anaplasma
Mycoplasmal
Bacterial: bartonella
Viral: distemper
“spiderman” cells = what disease?
babesia
This parasite achieves schizogony in what blood cell?
lymphocytes
this parasite = theileria
species in USA ruminants are usually non-pathogenic
name this parasite!
cytauxzoon felis
name this parasite! hint: can be transmitted by ticks
anaplasma
Name this infectious agent. Hint: this slide is from a cat.
Mycoplasma
Image is from the same infectious agent with two different stains. Bottom stain is Diff-Quik. What is the infectious agent?
Distemper virus
What is anemia and its clinical signs?
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
Seeing marrow precursor cells in a blood smear indicates what?
regenerative anemia
How long does reticulocyte maturation take in dogs?
24-48 hours
What is the difference between the cells marked “A” and the cells marked “P” in the slide?
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
These two slides show two different stains of what RBC developmental stage?
reticulocytes (in dog blood)
two stains are: wright-giemsa on left, new methylene blue on right
How long does it take reticulocytes to mature in dogs? cats?
dogs - one day
cats - aggregate to punctate in one day, punctate to mature in a week or more
What is a relative reticulocyte count and how can you use it?
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
Why do you not see reticulocytes in equine blood smears?
retics almost never released into circulation - maturation confined to the bone marrow
If anemia is present and your reticulocyte concentration is 5000 cells/microliter… are you concerned?
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
What does the presence of a regenerative response tell you about the cause of an anemia?
anemia caused by hemorrhage or increased erythrocyte destruction, not decreased erythrocyte production
How many days does it take for an animal to increase its RBC synthesis and release reticulocytes from bone marrow?
3-4 days
How does the degree of anemia affect the reticulocyte percentage?
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%
