ch.24alterations in erythron

Question 1

Why are indicators of regeneration, such as polychromasia and reticulocytosis absent or unreliable in the horse?

Answer 1

because RBCs remain in bone marrow until fully matured before they are released into circulation

Question 2

The mean cell volume represents what?

Answer 2

the average erythrocyte volume

Question 3

What does an increased MCV mean?

Answer 3

regenerative anemia in the ruminant
**occasionally in the horse

Question 4

What does a decreased MCV mean?

Answer 4

iron deficiency anemia (also copper)

**can be seen in healthy calves & foals

Question 5

define MCHC

Answer 5

mean cell hemoglobin concentration
–Hgb concentration per average erythrocyte & is calculated from the GB concentration & HCT

Question 6

What does decreased MCHC mean?

Answer 6

iron deficiency anemia
–regenerative anemias in cattle

Question 7

What does an increased MCHC mean?

Answer 7

typically false increases: hemolyzed, severely icteric or lipemic samples

Question 8

define anisocytosis

Answer 8

variation in erythrocyte size

Question 9

increased anisocytosis indicates

Answer 9

a regenerative anemia in ruminants

Question 10

polychromasia in erythrocyte means

Answer 10

slightly immature, macocyctic cells that appear blue-gray on Wright-stained blood smear d/t retained cytoplasmic ribonculeic acid

Question 11

increased polychromasia seen in RBCs

Answer 11

indicates a regenerative response
**polychromatophilic erythrocytes are relatively analogous to reticulocytes

Question 12

define howell jolly bodies

Answer 12

circular structures consisting of nuclear material within erythrocytes

Question 13

increased howell jolly bodies are seen in

Answer 13

regenerative anemias
splenic dysfunction

Question 14

In cattle Howell-Jolly bodies look similar to what organism?

Answer 14

Anaplasma marginale

Question 15

small numbers of nucleated rbcs with polychromasia seen in ruminants indicates?

Answer 15

regernative anemia

Question 16

increased circulating nucleated rbcs can be indicative of

Answer 16

bone marrow damage–> toxic damage, hypoxia, neoplasia

Question 17

the presence of nucleated RBCs and basophilic stippling in the absence of significant anemia should prompt consideration of what diagnosis?

Answer 17

lead toxicity (more common in ruminants)

Question 18

define basophilic stippling

Answer 18

multiple small basophilic inclusions within erythrocytes d/t staining of ribosomal aggregates

Question 19

when is basophilic stippling seen?

Answer 19

with regenerative anemias in ruminants
**Can be seen with lead toxicity in presence of nRBCs

Question 20

Heinz bodies form in erythrocytes as a result of

Answer 20

oxidative damage that leads to precipitation of Hgb

Question 21

List potential causes of heinz bodies

Answer 21

wilted red maple leaves
onions
garlic
phenothiazine
Brassica spp
copper toxicity

Question 22

Heinz body formations causes affected erythrocytes to be more susceptible to?

Answer 22

**more susceptible to both intravascular & extravascular hemolysis

Question 23

what is another rbc morphology (besides Heinz body formations) that are indicative of oxidative damage?

Answer 23

Eccentrocytes

Question 24

Define eccentrocytes

Answer 24

partial fusion of RBC membrane causing displacement of HgB contents to one side of the erythrocyte

Question 25

Eccentrocytes have been reported in horses with what two rare erythrocyte enzyme deficiencies

Answer 25

glucose-6-phosphate dehydrogenase deficiency
flavin adenine dinucleotide deficiency
**makes affected RBCs more susceptible to oxidative damage by endogenous or exogenous sources

Question 26

what rbc morphology is seen normally seen in healthy horses, but not healthy ruminants

Answer 26

roulleux

Question 27

describe agglutination of rbcs

Answer 27

is a result of surface-associated antibody on erythrocytes causing clumping

Question 28

What erythrocyte parasites can be seen on peripheral blood smears?

Answer 28

Mycoplasma spp
Anaplasma spp
theileria spp
babesia spp

Question 29

What does the Coombs test, test for?

Answer 29

used to detect erythrocyte surface associated antibody

Question 30

A Positive Coombs test is supportive of what diagnosis?

Answer 30

IMHA (including neonatal isoerythrolysis)

Question 31

Does a negative Coombs test the rule out IMHA?

Answer 31

No– b/c this test is known to have a relatively low sensitivity

Question 32

How long does it take for the bone marrow to respond to severe hemolysis in ruminants vs horses?

Answer 32

Ruminants: 2 to 4 days to see polychormasia/reticulocytes; peak bone marrow response w/in 7 days; may take 2 to 4 wks or more in ruminants for HCT to return to normal after an episode of hemorrhage or hemolysis

Equine: sluggish– may take u p to 1 to 2 months following severe hemolysis or 2 to 3 months following severe hemorrhage for HCT values to return to normal

Question 33

Causes of anemia in the horse due to BLOOD LOSS

Answer 33

trauma, surgery, ectoparasites (lice, ticks) endoparasites (strongyles), GI bleeding (ulcers, neoplasia) IMHA, Equine purpura hemorrhagica

DIC, guttural pouch mycosis, hematuria, hemoabdomen, moldly sweet lover toxicosis, rodenticide toxicosis, congenital coagulation factor deficiencies (hemophilia A), platelet function disorders

Question 34

Causes of anemia in the horse due to HEMOLYSIS

Answer 34

neonatal isoerthryolysis, red maple leaf toxicosis, equine infectious anemia

DIC?vasculitis, IMHA, secondary IMHA (clostridial infections, penicillin, therapy) lymphoma, theileriosis/Babesisos, onion toxicosis, phenothiazine toxicosis, glucose-6-phosphate dheydrogenase deficiency

Question 35

Cause of anemia in the horse due to DEC RBC production

Answer 35

anemia of chronic inflammation (chronic abscessation, pneumonia, pleuritis, lymphoma)
anemia of chronic renal failure, bone marrow neopasia (leukemia, met neopplasia) myelobfibrosis, apalstic anemia (idiopathic, drug including phenylbutazone)

Question 36

Cause of anemia in ruminants due to BLOOD LOSS

Answer 36

trauma, endoparasites (haemonchus sp. & liver flukes), ectoparasites (lice, ticks), abomasal ulcers, bleeding, acute asevere salmonella hemorrhagic diarrhea, oak toxicosis iwth hemorrhagic diarrhea, hemorrhagic bowel syndrome (jejunal hemorrhage syndrome)

hemorrhagic enteritis, hemoadbomen, bleeding diathesis assoc with DIC, moldly sweet clover toxicosis, caudal vena caval syndrome, severe acute pyelnonephritis, BVDV mucosal dz complex

Question 37

cause of anemia in ruminants d/t hemolysis

Answer 37

BVDV vaccine, anaplasmosis, Brassica spp toxicosis, Leptospirosis, onion toxicosis, clostridial infections, chronic copper toxicosis, water deprivation or salt poisoning following by ingestion of fresh water

babesiosi/theileriosis, mycoplasma spp infection, postparurient hemoglobinuria, immune mediated hemolytic anemia

Question 38

causes of anemia in ruminants d/t decreased RBC production

Answer 38

anemia of inflammatory disease, chronic pneumonia, chronic abscessation, Johnes disease, chronic BVDV, lymphoma
anemia of chronic renal failure, bracken fern toxicosis, radiation tox, myelofibrosis (pygmy goats) myelophthisis

Question 39

Erythrocytosis (polycythemia) refers to

Answer 39

an increased RBC count

Question 40

Hemoconcentration is most often due to

Answer 40

dehydration & loss of plasma volume

Question 41

Endotoxic shock can result in hemoconcentration because

Answer 41

increased vascular permeability & subsequent fluid shifts form the intravascular to extravascular space

Question 42

absolute erythrocytosis can be due to primary or secondary increases in erythropoeisis, differentiate between the two

Answer 42

1. primary: d/t INC EPO levels or activity— d/t chronic hypoxemia, such as chronic pulmonary disease, R to L CV shunting or animals living at a high altitude
2. Tumor producing EPO or EPO-like substances