RBC morphology and blood groups
what is the order from largest to smallest RBC size (MCV) in mammals?
dogs>cows>cats>horses
what 3 values do you look at to determine anemia?
HCT/PCV, Hgb, RBC
what is hemostasis
a sequence of events that stops bleeding
what is the main goal of secondary hemostasis
formation of fibrin clot
what is the goal of tertiary hemostasis and what is the pathophysiology?
fibrinolysis
in order to remove the clot, endothelium releases tPA - tPA activates plasminogen to plasmin - plasmin hydrolyzes fibrin fibers into FDPs - FDPs are removed by macrophages
describe the main characteristics of exotics RBCs
Nucleated
aerobic metabolism
large elliptical cells
What value on CBC is the best indicator of regenerative anemia?
Reticulocytosis
-not seen in horses, so you need to see if there is macrocytosis
what occurs in primary hemostasis?
vascular spasm and platelet plug formation
what clotting factors are in the intrinsic pathway?
12, 11, 9, 8
what are the clinical signs of a primary hemostatic disorder
petechia and mucosal bleeding
what type of RBC distribution is seen in healthy horses but can be pathologic in other animals?
Rouleau
What does this mean in other animals? hyperglobulinemia and/or hyperfibrinogenemia - can be due to inflammation and/or dehydration
what are 3 additional indicators of RBC regeneration?
Howell-Jolly bodies, metarubricytes, basophilic stippling in cattle
what are 2 diseases that cause thrombocytopenia?
Rickettsial diseases and von Willebrand disease
what clotting factors are in the extrinsic pathway?
3 and 7
what are the clinical signs specific to secondary hemostasis?
large hematomas, cavity bleeding, frank hemorrhage
When performing a blood smear, you find poikilocytosis such as schizocytes or keratocytes. What type of injury has likely occurred?
Vasculitis
What are the 2 most common causes of non-regenerative anemia?
anemia of inflammatory disease
anemia of chronic renal failure
what is released during vasospasm
sympathetic stimulation by norepinephrine
release of endothelin, thromboxane A2, ADP, and serotonin
what are the clotting factors in the common pathway?
10, 5, 2, 1
how can you tell the difference between regenerative and non-regenerative anemia by RBC indices?
regenerative - MCV: macrocytic, MCHC: hypochromic
non-regenerative - MCV: microcytic or normocytic, MCHC: hypochromic or normochromic
You are running bloodwork on a dog that has come into the clinic for an annual exam. Bloodwork shows decreased RBCs and an increase in MCV. What is most likely occurring, and what additional test should be done?
most likely agglutination is occuring and a saline agglutination test should be done to confirm.
failure to disperse is indicative of IMHA
dispersion indicates dehydration/inflammation
what is the difference in pathogenesis of extravascular and intravascular hemolytic anemias?
extravascular - macrophages engulf and lyse RBCs in the spleen, spheroctes in dogs, macrophages degrade hemoglobin to bilirubin and overwhelms the liver causing icterus, hyperbilirubinemia, bilirubinuria
intravascular - marked damage to RBC membrane, erythrocytes lyse within the blood vessels and cause anemia, hemoglobin is present in plasma and urine - hemoglobinemia and hemoglobinuria
what happens to platelets once they are activated?
change shape - oval to star shape
cytoskeletal reorganization
granule release
expression of surface receptors: GP IIb/IIIa
production of TXA2
what clotting factors are dependent of vitamin K?
2, 7, 9, 10
what tests are used to diagnose intrinsic pathway or extrinsic pathway disorders?
intrinsic: APTT and ACT
extrinsic: PT