Hematology - Levine Regenerative Anemia SG Flashcards
What is the body’s normal response to anemia, and what hormone regulates this?
The bodies normal response to anemia is accelerated erythropoiesis
Erythropoietin (EPO) regulates this
EPO release is induced by _______ _______.
renal hypoxia
What is the most useful marker of regeneration?
Increased number of reticulocytes
What is a reticulocyte?
An immature non-nucleated erythrocytes
What two stains can be used to visualize reticulocytes on a blood smear?
New methylene blue
Brilliant cresyl blue
What are the two types of cat reticulocytes, and what is the difference between the two?
Cats have aggregate and punctate reticulocytes
Punctate reticulocytes have few basophilic granules and are in circulation for several weeks
Which type of feline reticulocyte tells you about an acute anemia and is the one that is reported by the lab?
Aggregate reticulocytes
What is the formula to calculate the absolute reticulocyte count?
Absolute reticulocyte count = RBC count x RP
RP is reticulocyte percentage
What else on a CBC can provide evidence of regeneration?
Increased MCV
Increased RDW
Decreased MCHC
Polychromasia
Howell-Jolly bodies
What is the canine blood volume in ml/kg?
Canine – 8-10% body weight; 90 ml/kg
What is the feline blood volume in ml/kg?
Feline – 6-8% of body weight; 60 ml/kg
If you have a 2 kg kitten, what is its blood volume in ml?
120 ml
If you can safely sample 10% of an animal’s blood volume for diagnostic testing, how much volume can you sample from a 2kg kitten?
12 mL
A dog presents to you with a regenerative anemia. Which of the following steps are appropriate in determining the cause of his anemia?
a. Evaluate his total protein
b. Evaluate his blood smear for spherocytes
c. Obtain a thorough drug history
d. Perform a bone marrow exam
e. All of the above
f. All of the above except d
f. All of the above except d
What happens in the body initially with acute blood loss anemia (protective mechanisms)?
Peripheral vasoconstriction and tachycardia
Regional blood flow to the skin and spleen is curtailed to protect perfusion to the brain, heart, and viscera
Why are the PCV and TP initially normal with an acute bleed?
All blood components are lost in similar proportions
Splenic contraction plays a role early in the process, causing a transient increase in PCV
How long after an acute bleed do you see a fall in PCV/TP? Why?
2-3 hours after the onset of bleeding, and continuing for 48-72 hours, blood volume replacement occurs by the addition of interstitial fluid
Plasma volume increases, diluting cells, and protein
How long after an acute bleed would you expect to see a rise in TP (as long as the bleeding has stopped)?
2-3 days after a bleed
After a blood loss event, when is the maximal retic response seen?
3-4 days after the bleed
What three clinicopathologic markers are typically present with external blood loss?
Anemia
Hypoproteinemia
Reticulocytosis
What are the four main objectives in the management of acute blood loss?
Stop bleeding and prevent further bleeding
Replace lost red cells
Careful volume resuscitation
Treatment of an underlying disorder
Why can depletion of RBC mass be difficult to estimate in acute blood loss?
Due to concurrent plasma loss; the HCT decreases only after the total blood volume returns to normal
What is the major cause of iron deficiency anemia in cats and dogs?
Chronic external blood loss
Where is most iron located in the body?
In RBC’s as hemoglobin
List some common causes of chronic blood loss in cats and dogs:
Fleas
Hookworms
Bleeding GI neoplasia
Ulcerogenic drugs like NSAIDs and glucocorticoids
Frequent phlebotomy
What would you expect the MCHC and MCV to be in severe iron deficiency anemia?
Microcytic and hypochromic or microcytic and normochromic
Why does microcytosis occur in iron deficiency anemia?
RBCs continue to divide in order to obtain ideal Hgb concentration per cell
What is the normal lifespan of the canine erythrocyte? Feline erythrocyte?
Dog -120 days
Cat – 70 days
What is extravascular hemolysis?
RBCs are degraded within macrophages, so no hemoglobin is released from the cytoplasm therefore there is no hemoglobinuria or hemoglobinemia
Also accompanied by bilirubinemia and bilirubinuria
What is intravascular hemolysis?
RBCs are lysed within the circulation as a result of membrane permeability changes or cellular fragmentation
Hemoglobin is directly released into the blood
Hemoglobinuria ensues when the amount filtered through the kidney exceeds the limited capacity of the tubule to resorb hemoglobin
Clinically, how can you tell the difference between intravascular and extravascular hemolysis?
You will have hemoglobinemia and hemoglobinuria in intravascular hemolysis and not in extravascular
Look at the following CBC. Calculate the absolute reticulocyte count. Determine if the anemia is regenerative.
2.93x106x .0393 = 117,114
In a dog, anything over 80,000 is regenerative
Why do you think this dog is anemic? (Hint: look closely at the urinalysis, color vs. sediment examination results.)
Not entirely sure about this one but I think it is extravascular hemolysis because of the bilirubinuria
