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What is anemia?
decrease in the oxygen carrying capacity of the blood, decrease in RBC count
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What test can we do in the clinic to test for anemia?
PCV - a decrease in PCV indicates anemia
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Is anemia a disease?
no, its a clinical sign
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What are the clinical signs of anemia?
- pale mucous membranes
- weakness, tire easily
- syncope
- tachycardia
- tachypnea
- cool extremities
- heart murmur
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What is syncope?
fainting
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Is a heart murmur caused by anemia reversable? And if so, how is reversed?
- yes
- as soon as anemia is corrected, heart murmur is corrected
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Can clinical signs of anemia vary?
yes, the more anemic the more severe the clinical signs.
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Where are red blood cells mainly made? Where are other places red blood cells are made?
- bone marrow
- can also be made in the spleen, nodes, and liver
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How long is the life span of red blood cells in dogs and cats?
- dogs: 110 days
- cats: 70 days
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What are red blood cells and what do they do?
- contain hemoglobin
- carries oxygen
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If loss of red blood cells is greater than the production of red blood cells, then what occurs?
anemia
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Can anemia be life threatening?
yes
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Where are red blood cells broken down?
in the reticuloenothelial system
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What does hemoglobin break down to?
- globin
- iron
- unconjugated bilirubin
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What parts of hemoglobin are reused and which are not?
- globin and iron are reused
- unconjugated bilirubin is taken to the liver and changed to conjugated bilirubin which is then passed in urine and feces
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What is erythropoietin?
hormone that is released to stimulate the production of RBC
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Where does erythropoietin come from?
the juxtaglomerular apparatus of the kidney
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How is erythropoietin stimulated?
when oxygen levels drop below a certain level erythropoietin is released from the kidney. this stimulates the bone marrow to release RBCs and in crease RBC production
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If erythropoietin is present in anemia then is it regenerative or nonregenerative?
regenerative anemia
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How do we evaluate RBCs?
- PCV
- RBC count and hemoglobin
- erythrocyte morphology
- reticulocyte count
- bone marrow aspiration
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When is a reticulocyte count useful?
only when we know the patient is anemic and when we want to determine if the anemia is responsive or non-responsive
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What is a normal PCV for dogs, cats, horses, cows?
- dogs: 45%
- cats: 37%
- horses: 42%
- cows: 34%
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Which test is the most accurate to test for anemia?
PCV
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With what kind of stain do we see reticulocytes?
NMB
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Can we stain RBCs with NMB and then with Diff Quik?
yes
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How many reticulocytes are considered normal in dogs?
1%
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Reticulocytes increase with which type of anemia?
responsive
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When we look at for reticulocytes in cats which ones do we count? Which ones do we not count?
cont the aggregate ones and don't count the punctate ones
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Do normal large animals have reticulocytes in the peripheral blood?
no
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When do we see reticulocytes in ruminants?
- in responsive anemia
- no need to count them because if any exist then they have responsive anemia
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Where do we find reticulocytes in horses? Do they ever have any in the peripheral blood?
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If a dog is anemic how many reticulocytes can we see?
up to 50%
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How do we do a manual reticulocyte count?
- mix blood with NMB (1:1)
- let it sit in the NMB for 10 minutes
- make a blood smear
- count reticulocytes per 1, 000 RBCs
- divide by 10 to get %
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Why do we need to do a corrected reticulocyte count?
must correct for the fewer mature RBCs in an anemic animal
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How do we do a corrected reticulocyte count?
multiply observed retic count times observed PCV/normal range (45% for dogs, 35% for cats)
retic count (%) x actual PCV/normal PCV
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Will the corrected reticulocyte count always be lower than the observed count?
yes
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How do we get an absolute retic count?
multiply corrected retic %'s by RBC count
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What are the two causes of regenerative anemia?
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What causes blood loss anemia?
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What causes hemolytic anemia?
IMHA, HBHA, blood parasites
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What is IMHA?
immune mediated hemolytic anemia
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What is HBHA?
heinz body hemolytic anemia
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What does hemolytic anemia mean?
more RBCs are being destroyed than replaced
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How long can it take for us to see a reticulocyte response?
may take up to 7 days
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What is anisocytosis?
variation in size of RBC
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Which animal is anisocytosis normal?
cows
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What type of anemia do we see anisocytosis?
responsive anemias
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What is polychromasia?
variation in RBC color from blue to red
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What causes polychromasia?
increased reticulocytes
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What are Howell Jolly Bodies?
- nuclear reminant
- one per cell
- blue dot anywhere in the cell
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What can we confuse Howell Jolly Bodies with?
parasites
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What kind of anemia do we usually see Howell Jolly Bodies in?
responsive anemia
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What is another name for a nucleated RBC?
metarubricyte
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When will we see metarubricytes?
in responsive anemias
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What can machines confuses metarubricytes with?
WBCs
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Is it possible to see some metarubricytes in normal animals?
yes
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If we have an animal with nonspecific GI symptoms and metarubricytes what is the most likely cause?
lead poisoning
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How do we do a corrected WBC count?
- count nucleated RBCs as part of differential (100 cells)
- calculate absolute number by multiplying % x leukocyte count
- subtract from total leukocyte count
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What is autoagglutination?
clumpingof RBCs
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What can agglutination be easily confused with?
rouleaux
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Which type of anemia is agglutination usually seen in?
IMHA
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What are spherocytes?
- round RBC with no central pallor and usually smaller than a normal RBC
- stain denser than a normal RBC
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Which type of anemia are spherocytes usually seen in?
IMHA
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What are spherocytes often associated with?
agglutination
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What are heinz bodies?
denatured hemoglobin
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Where are heinz bodies usually located?
on edge of RBC
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What do heinz bodies look like when stained with DQ? NMB?
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What can heinz bodies be confused with in cats?
erythrocyte refractile bodies
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What usually causes heinz bodies?
toxcities
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What types of toxicities cause heinz bodies?
- acetominophen
- methylene blue (found in cleaners)
- onions
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What is basophilic stipling?
blue dots in RBCs stained with DQ
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What usually causes basophilic stipling?
lead poisoning
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Lead toxicity may cause what?
anemia
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What is mycoplasma haemofelis?
small blue dot on edge of RBC in cats
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What is the first thing we look for when we have an anemic cat?
mycoplasma haemofelis
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What can mycoplasma haemofelis cause?
feline infectious anemia
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What other parasites can cause anemia?
- ehrlichia
- anaplasma
- babesia
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What tests can determine blood parasites?
- snap
- PCR
- serological tests
- blood smear
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What is affected by non-regenerative anemia?
bone marrow
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What are the 4 mechanisms of non-regenerative anemia?
- destruction
- depression
- depletion
- degeneration
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What causes non-regenerative anemia?
- renal disease
- infections
- drugs
- neoplasia
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What is MCV stand for? What is it?
- mean corpuscular volume
- average size of RBC
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How do we determine the MCV?
PCV divided by RBC count (in scientific notation) x 10
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What is it called if MCV is normal? Above normal? Below normal?
- normal: normocytosis
- above normal: macrocytosis
- below normal: microcytosis
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What are most macrocytic anemias?
regenerative
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What is microcytic anemia usually due to?
Fe deficiency
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What does MCHC stand for? What is it?
- mean corpuscular hemoglobin concentration
- average hemoglobin in RBC
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How do we determine the MCHC?
HbG/PCV x 100
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What is the normal range for MCHC?
normochromia: between 31 and 36
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Does hyperchomia exist?
no
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If a MCHC is smaller than 31 what does it mean?
hypochromia
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What is hypochromia?
large pale area in center of RBC
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What causes hypochromia?
decrease in HbG due to blood loss or decrease in iron
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Why would we do a bone marrow biopsy?
- to find a cause for unexplained increase or decrease in blood cells
- can tell if anemia is regenerative
- evaluate normal WBCs and RBCs
- can determine if cells are abnormal
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What is wrong with these RBCs?
agglutination
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What is on this WBC?
Ehrlichia or Anaplasma
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What is wrong with these RBCs?
anisocytosis
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What parasite is on these RBCs?
Babesia
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Which ones are aggregates and which ones aare punctate?
- aggregates: the RBCs with more blue dots
- punctate: the RBCs with only a couple blue dots
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What is on these RBCs?
heinz bodies
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What is on these RBCs?
heinz bodies
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What is on this RBC?
howell jolly body
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What is wrong with these RBCs?
hypochromia
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What does this indicate?
leukemia
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What is this?
mast cell
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What is this?
metarubricytes
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What are on the edges of this cat's RBCs?
mycoplasma haemofelis
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What is wrong with these RBCs?
polychromasia
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What are the smaller RBC's called?
spherocytes
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List 3 general physiologic mechanisms by which anemias are produced.
- blood loss
- hemolysis
- bone marrow destruction
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List 5 different specific causes of anemia.
- bleeding
- parasites (internal and external)
- renal disease
- infections
- drugs
- neoplasia
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List 2 ways the lab findings in autoimmune hemolytic anemias differ from those in other types of anemias.
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What is the significance of a Heinz body hemolytic anemia? List three causes of a HBHA.
- denatured hemoglobin
- acetominophen, methylene blue (in cleaners), onions
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List 4 findings you may see in a Diff Quik stained blood smear from an animal with a responsive anemia.
- autoagglutination
- spherocytes
- heinz bodies
- basophilic stipling
- mycoplasma haemofelis
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A dog has a PCV of 18%. You count 36 reticulocytes/1000 rbcs on the blood smear.
What is the observed reticulocyte count?
What is the corrected reticulocyte count?
Is this a responsive anemia?
In the absence of a reticulocyte count, how else could you determine if the anemia is responsive?
- 3.6%
- observed retics x (observed PCV/normal PCV)...3.6% x (18%/45%) = 1.4%
- yes, slight
- check a blood smear for erythrocyte morphology
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A dog has a PCV of 21%, an erythrocyte count of 3,000,000/dl and a hemoglobin of 2 gm/dl.
What is the MCV?
What is the MCHC?
Based on the above how would you classify the anemia?
- (PCV/RBC)x10...(21/3)x10=70
- (HbG/PCV)x100...(2/21)x100=9.5
- normocytic, hypochromic anemia
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