Vascular Disorders & Thrombosis 3 Flashcards
Primary hemostasis:
What test is used to measure platelet count?
CBC
Primary hemostasis:
What test is used to measure platelet global number and function?
Buccal mucosal bleeding time (BMBT)
Primary hemostasis:
What test is used to measure von Willebrand factor?
vWF antigen concentration
Primary hemostasis:
What test is used to assess the vessel wall?
Biopsy
Secondary hemostasis:
What test is used to assess the extrinsic pathway (VII)?
Prothrombin time (PT)
Secondary hemostasis:
What test is used to assess the intrinsic pathway (XII, XI, IX, X)?
Activated partial thromboplastin time (aPTT)
Fibrinolysis:
What tests are used to measure products of degradation?
FDPs, D-dimer
Fibrinolysis:
What tests are used to measure protein activity or concentration?
t-PA, plasminogen
Trauma, inflammation, invasive neoplasms, infectious agents, endotoxemia, uremic toxins, immune complexes, and collagen disorders can all lead to ______________ injury.
Endothelial
Rickettsia rickettsii, a tick-borne bacteria, causes which illness in dogs?
Rocky Mountain spotted fever
What is the pathogenesis of Rocky Mountain spotted fever?
- Bacteria invade and replicate within endothelial cells of small blood vessels, leading to endothelial injury
- Endothelial injury causes hemorrhage and thrombosis, leading to DIC
What are some clinical signs of Rocky Mountain spotted fever?
Fever, anorexia, lymphadenopathy, polyarthritis, edema, petechiae, ecchymoses
What are some laboratory findings commonly seen in Rocky Mountain spotted fever?
Anemia, thrombocytopenia, prolongation of aPTT, hyperfibrinogenemia, and increased FDP concentrations
Erysipelothrix rhusiopathiae causes which illness in swine?
Swine erysipelas or “diamond skin disease”
What is the pathogenesis of swine erysipelas/“diamond skin disease”?
- 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)
Decrease in platelet numbers
Thrombocytopenia
(Decreased production: e.g. bone marrow suppression)
(Increased consumption: e.g. immune-mediated, DIC)
Decrease in platelet function
Thrombocytopathy
(Can be inherited or acquired)
Inherited disorder caused by lack of von Willebrand factor protein (vWF); highest incidence in Doberman Pinschers
Von Willebrand disease (vWD) in dogs
What are some clinical signs of vWD?
- Mild to severe bleeding tendency
- Spontaneous bleeding from the nose/mouth/urinary tract/repro tract/GI tract
- Excessive bleeding after surgery
True or False: vWD is associated with decreased vWF antigen, but normal platelet number, PT/aPTT, and FDP/D-dimer
True
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?
Greyhounds
(Cause unknown - no defect in primary/secondary hemostasis)
Antibody-mediated platelet destruction that can be secondary to infection, drug administration, neoplasia, and other immune-mediated disease; often involves hemorrhage in multiple organs
Immune-mediated thrombocytopenia (IMTP) in dogs
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
Equine Infectious Anemia
Warfarin, brodifacoum, and moldy sweet clover are all vitamin K _______________.
Antagonists
(Remember: Warfarin is an anticoagulant found in prescription medications and some rodenticides!)
What is the basic pathogenesis of rodenticide toxicosis?
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)
What are some clinical signs of rodenticide toxicosis?
Mild hemorrhage to severe spontaneous bleeding
(epistaxis, melena, hematuria, SQ hemorrhage, hemothorax, thymic hemorrhage, hemarthrosis, etc.)
True or False: Rodenticide toxicosis is associated with normal platelet count and decreased PT/aPTT
False; normal platelet count and PROLONGED PT/aPTT
(Remember: Vit-K dependent coag facters = II, VII, IX, and X)
