Blood work

Question 1

Name toxic changes in the leukogram

Answer 1

• basophilia
• granulation
• vacuolation of the cytoplasm
• scalloped cell borders
• adherence of neutrophils to RBC

–> reflect action of cells to inflammatory mediators such as TNF-alpha, IL-1 and inflammatory mediators produced by neutrophils (toxic to bacteria) , degree of changes can be used to assess severity and monitor progress

Question 2

How does anemia of chronic disease (chronic inflammation) occur?

Answer 2

decreased erythrogenesis secondary to iron sequestration by bone marrow macrophages

Question 3

What is considered thrombocytopenia and at what point can clinical bleeding be expected in horses?

Answer 3

Thrombocytopenia: <100 000/ul
bleeding: >30 000/ul

Question 4

What does activated clotting time assess and deficiency in which factors prolong it?

Answer 4

secondary hemostasis, intrinsic and common pathways

5, 8, 9, 10, 11, prothrombin, fibrinogen

Question 5

What does partial thromboplastin time assess (PTT) and deficiency in which factors prolong it?

Answer 5

intrinsic and common pathways
higher sensitivity than ACT

5, 8, 9, 10, 11, 12, prothrombin, fibrinogen

Question 6

What is the difference between PTT and aPTT

Answer 6

with activated PTT a contact activator is added to the blood sample (kaolin, silicates, ellagic acid)

Question 7

What genetic diseases may cause prolonged PTT and aPTT in horses?

Answer 7

hemophilia A
plasma prekallikrein deficiency

Question 8

What does prothrombin time assess and deficiency in which factors prolong it?

Answer 8

extrinsic and common pathways

specifically ability to convert fibrinogen to fibrin

Prolongation with deficiency of: tissue factor (3), 5, 7, 10, prothrombin and fibrinogen
also: Vitamin K deficiency

Question 9

What does thrombin time assess and deficiency in which factors prolong it?

Answer 9

terminal common pathway, secondary hemostasis

Prolongation with deficiency in: fibrinogen
FDPs can prolong as well