ch.24alterations in erythron Flashcards
Why are indicators of regeneration, such as polychromasia and reticulocytosis absent or unreliable in the horse?
because RBCs remain in bone marrow until fully matured before they are released into circulation
The mean cell volume represents what?
the average erythrocyte volume
What does an increased MCV mean?
regenerative anemia in the ruminant
**occasionally in the horse
What does a decreased MCV mean?
iron deficiency anemia (also copper)
**can be seen in healthy calves & foals
define MCHC
mean cell hemoglobin concentration
–Hgb concentration per average erythrocyte & is calculated from the GB concentration & HCT
What does decreased MCHC mean?
iron deficiency anemia
–regenerative anemias in cattle
What does an increased MCHC mean?
typically false increases: hemolyzed, severely icteric or lipemic samples
define anisocytosis
variation in erythrocyte size
increased anisocytosis indicates
a regenerative anemia in ruminants
polychromasia in erythrocyte means
slightly immature, macocyctic cells that appear blue-gray on Wright-stained blood smear d/t retained cytoplasmic ribonculeic acid
increased polychromasia seen in RBCs
indicates a regenerative response
**polychromatophilic erythrocytes are relatively analogous to reticulocytes
define howell jolly bodies
circular structures consisting of nuclear material within erythrocytes
increased howell jolly bodies are seen in
regenerative anemias
splenic dysfunction
In cattle Howell-Jolly bodies look similar to what organism?
Anaplasma marginale
small numbers of nucleated rbcs with polychromasia seen in ruminants indicates?
regernative anemia
increased circulating nucleated rbcs can be indicative of
bone marrow damage–> toxic damage, hypoxia, neoplasia
the presence of nucleated RBCs and basophilic stippling in the absence of significant anemia should prompt consideration of what diagnosis?
lead toxicity (more common in ruminants)
define basophilic stippling
multiple small basophilic inclusions within erythrocytes d/t staining of ribosomal aggregates
when is basophilic stippling seen?
with regenerative anemias in ruminants
**Can be seen with lead toxicity in presence of nRBCs
Heinz bodies form in erythrocytes as a result of
oxidative damage that leads to precipitation of Hgb
List potential causes of heinz bodies
wilted red maple leaves
onions
garlic
phenothiazine
Brassica spp
copper toxicity
Heinz body formations causes affected erythrocytes to be more susceptible to?
**more susceptible to both intravascular & extravascular hemolysis
what is another rbc morphology (besides Heinz body formations) that are indicative of oxidative damage?
Eccentrocytes
Define eccentrocytes
partial fusion of RBC membrane causing displacement of HgB contents to one side of the erythrocyte
Eccentrocytes have been reported in horses with what two rare erythrocyte enzyme deficiencies
glucose-6-phosphate dehydrogenase deficiency
flavin adenine dinucleotide deficiency
**makes affected RBCs more susceptible to oxidative damage by endogenous or exogenous sources
what rbc morphology is seen normally seen in healthy horses, but not healthy ruminants
roulleux
describe agglutination of rbcs
is a result of surface-associated antibody on erythrocytes causing clumping
What erythrocyte parasites can be seen on peripheral blood smears?
Mycoplasma spp
Anaplasma spp
theileria spp
babesia spp
What does the Coombs test, test for?
used to detect erythrocyte surface associated antibody
A Positive Coombs test is supportive of what diagnosis?
IMHA (including neonatal isoerythrolysis)
Does a negative Coombs test the rule out IMHA?
No– b/c this test is known to have a relatively low sensitivity
How long does it take for the bone marrow to respond to severe hemolysis in ruminants vs horses?
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
Causes of anemia in the horse due to BLOOD LOSS
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
Causes of anemia in the horse due to HEMOLYSIS
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
Cause of anemia in the horse due to DEC RBC production
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)
Cause of anemia in ruminants due to BLOOD LOSS
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
cause of anemia in ruminants d/t hemolysis
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
causes of anemia in ruminants d/t decreased RBC production
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
Erythrocytosis (polycythemia) refers to
an increased RBC count
Hemoconcentration is most often due to
dehydration & loss of plasma volume
Endotoxic shock can result in hemoconcentration because
increased vascular permeability & subsequent fluid shifts form the intravascular to extravascular space
absolute erythrocytosis can be due to primary or secondary increases in erythropoeisis, differentiate between the two
- 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
- Tumor producing EPO or EPO-like substances
