Hematology - Anemia Flashcards
What is anemia?
Decrease in circulating RBC mass expressed by reduction in RBC count, hemoglobin, and Hct (PCV)
What is anemia caused by?
Decreased production, increased destruction, and increased loss
What are clinical signs of anemia due to?
Decreased O2 carrying capacity, reduced blood volume, and underlying disease
What do the severity of anemia signs depend on?
Rapidity of onset, degree and cause of anemia, and extent of physical activity
What is the normal response to anemia?
Accelerated erythropoiesis
How does accelerated erythropoiesis occur?
There is reduced oxygen carrying capacity which results in renal hypoxia. Renal hypoxia stimulates erythropoietin (EPO) release
After acute blood loss, dogs increase RBC production to __ to ___ times the normal rate.
6 to 8 times
After acute blood loss, cats increase RBC procution _ to _ fold.
3 to 5
What is the most useful marker of regeneration?
increased number of reticulocytes
What are reticulocytes?
immature non-nucleated erythrocytes
How long does it take reticulocytosis to develop? When does it peak? When does it decline in dogs? Cats?
Takes 2 to 4 days to develop.
Peaks between 4 and 7 days.
Declines at 2-3 weeks in dogs.
Declines in 9-13 days in cats.
What type of reticulocytes do cats have?
Aggregate and punctate
Which feline reticulocyte is present in the circulation for longer?
punctate
Which feline reticulocyte is counted in the laboratory reticulocyte count?
Aggregate
What is the reticulocyte percentage?
The percentage of RBC that are reticulocytes
What reticulocyte percentage indicates regenerative anemia in dogs? Cats?
0-1.0% in dogs, 0-0.4% in cats
How do you calculate the absolute reticulocyte count?
RBC count x RP
At what number of reticulocytes is considered to be a sign of regenerative anemia in dogs?
> 80,000 reticulocytes
At what number of reticulocytes is considered to be a sign of regenerative anemia in cats?
> 50,000 reticulocytes
True or False: Reticuocytes are the only absolute thing that you can use to determine if a patient has regnerative anemia.
TRUE
What are some other indicators of regeneration?
Increased MCV (macrocytic), increased RDW, decreased MCHC (hypochromic), polychromasia, and Howell-Jolly bodies
What is the hallmark of external blood loss? (Hint: it is a triad)
Anemia, hypoproteinemia, and reticulocytosis
What are some signs of a primary hemostatic defect?
Petechiae, ecchymoses, hematuria, melena, and epistaxis
What are some signs of a secondary hemostatic defect?
Hemoabdomen, hemothorax, hematomas, and joint bleeding
What factors can be measured to determine if there is a primary hemostatic defect?
Platelet count and von Willebrand factor (vWF)
What tests can be done to determine if there is a secondary hemostatic defect?
Coagulation times - PT and aPTT
Are there any clues on the CBC of acute bleed anemia?
Shistocytes (DIC and hemangiosarcoma) and possibly decreased platelets
Below what number of platelets are patients at risk for spontaneous bleeding?
below 30,000 platelets/microliter
If the cause of acute (regenerative) anemia is not obvious, what other diagnostics can be done? What should not be done?
Radiographs, ultrasound, and endoscopy
Bone Marrow evaluation is not indicated for a regenerative anemia
How much is the canine blood volume?
90 ml/kg - it is 8-10% of body weight
How much is the feline blood volume?
60 ml/kg - it is 6-8% of body weight
When hemorrhage is greater than 20% of blood volume, what signs occur?
cardiovascular signs