Vascular Disorders & Thrombosis 3

Question 1

Primary hemostasis:

What test is used to measure platelet count?

Answer 1

CBC

Question 2

Primary hemostasis:

What test is used to measure platelet global number and function?

Answer 2

Buccal mucosal bleeding time (BMBT)

Question 3

Primary hemostasis:

What test is used to measure von Willebrand factor?

Answer 3

vWF antigen concentration

Question 4

Primary hemostasis:

What test is used to assess the vessel wall?

Answer 4

Biopsy

Question 5

Secondary hemostasis:

What test is used to assess the extrinsic pathway (VII)?

Answer 5

Prothrombin time (PT)

Question 6

Secondary hemostasis:

What test is used to assess the intrinsic pathway (XII, XI, IX, X)?

Answer 6

Activated partial thromboplastin time (aPTT)

Question 7

Fibrinolysis:

What tests are used to measure products of degradation?

Answer 7

FDPs, D-dimer

Question 8

Fibrinolysis:

What tests are used to measure protein activity or concentration?

Answer 8

t-PA, plasminogen

Question 9

Trauma, inflammation, invasive neoplasms, infectious agents, endotoxemia, uremic toxins, immune complexes, and collagen disorders can all lead to ______________ injury.

Answer 9

Endothelial

Question 10

Rickettsia rickettsii, a tick-borne bacteria, causes which illness in dogs?

Answer 10

Rocky Mountain spotted fever

Question 11

What is the pathogenesis of Rocky Mountain spotted fever?

Answer 11

• Bacteria invade and replicate within endothelial cells of small blood vessels, leading to endothelial injury
• Endothelial injury causes hemorrhage and thrombosis, leading to DIC

Question 12

What are some clinical signs of Rocky Mountain spotted fever?

Answer 12

Fever, anorexia, lymphadenopathy, polyarthritis, edema, petechiae, ecchymoses

Question 13

What are some laboratory findings commonly seen in Rocky Mountain spotted fever?

Answer 13

Anemia, thrombocytopenia, prolongation of aPTT, hyperfibrinogenemia, and increased FDP concentrations

Question 14

Erysipelothrix rhusiopathiae causes which illness in swine?

Answer 14

Swine erysipelas or “diamond skin disease”

Question 15

What is the pathogenesis of swine erysipelas/“diamond skin disease”?

Answer 15

• Septicemia leads to bacterial embolization in the skin, causing vasculitis
• Vasculitis causes hemorrhage, thrombosis, ischemia, and infarct

(Result = multifocal, red/purple, rhomboid, slightly raised skin lesions)

Question 16

Decrease in platelet numbers

Answer 16

Thrombocytopenia

(Decreased production: e.g. bone marrow suppression)
(Increased consumption: e.g. immune-mediated, DIC)

Question 17

Decrease in platelet function

Answer 17

Thrombocytopathy

(Can be inherited or acquired)

Question 18

Inherited disorder caused by lack of von Willebrand factor protein (vWF); highest incidence in Doberman Pinschers

Answer 18

Von Willebrand disease (vWD) in dogs

Question 19

What are some clinical signs of vWD?

Answer 19

• Mild to severe bleeding tendency
• Spontaneous bleeding from the nose/mouth/urinary tract/repro tract/GI tract
• Excessive bleeding after surgery

Question 20

True or False: vWD is associated with decreased vWF antigen, but normal platelet number, PT/aPTT, and FDP/D-dimer

Answer 20

True

Question 21

Which breed is known to bleed spontaneously after minor trauma/surgery, and seems to have slower clot kinetics and weaker clot strength compared to other breeds?

Answer 21

Greyhounds

(Cause unknown - no defect in primary/secondary hemostasis)

Question 22

Antibody-mediated platelet destruction that can be secondary to infection, drug administration, neoplasia, and other immune-mediated disease; often involves hemorrhage in multiple organs

Answer 22

Immune-mediated thrombocytopenia (IMTP) in dogs

Question 23

Form of anemia caused by EIAV/lentivirus; infects cells of monocyte-macrophage system in horses; causes immune-mediated hemolysis and platelet destruction (anemia and thrombocytopenia); hemorrhage in multiple organs

Answer 23

Equine Infectious Anemia

Question 24

Warfarin, brodifacoum, and moldy sweet clover are all vitamin K _______________.

Answer 24

Antagonists

(Remember: Warfarin is an anticoagulant found in prescription medications and some rodenticides!)

Question 25

What is the basic pathogenesis of rodenticide toxicosis?

Answer 25

Inhibition of vitamin K epoxide-reductase in the body
- Decreased active reduced vitamin K
- Decreased production of vitamin K-dependent coag factors (II, VII IX, and X)

Question 26

What are some clinical signs of rodenticide toxicosis?

Answer 26

Mild hemorrhage to severe spontaneous bleeding

(epistaxis, melena, hematuria, SQ hemorrhage, hemothorax, thymic hemorrhage, hemarthrosis, etc.)

Question 27

True or False: Rodenticide toxicosis is associated with normal platelet count and decreased PT/aPTT

Answer 27

False; normal platelet count and PROLONGED PT/aPTT

(Remember: Vit-K dependent coag facters = II, VII, IX, and X)