Hemostasis 1

Question 1

what is the difference between primary and secondary hemostasis?

Answer 1

primary: platelet plug formation
secondary: cogulation cascade

Question 2

______ causes initial vasoconstriction when there is a vascular injury

Answer 2

endothelin

Question 3

what two things lead to platelet ahesion?

Answer 3

exposure to subendothelial collagen, and the adhesive protein von Willebrand factor

Question 4

what does vWF do to help clots form?

Answer 4

acts as a tether for platelets helping them adhere to the site of injury, and it’s esp important in vessels with high shear forces/high flow

Question 5

what are some common clinical signs for disorders of primary hemostasis?

Answer 5

superficial hemorrhages of the skin and mucosa: petechiae, purapura, ecchymosis, persistent oozing from incisions, spitaxsis, melena, hematochezia, hematuria

Question 6

what is the difference between thrombocytopenia and thrombopathia?

Answer 6

thrombocytopenia is decreased platelets
thrombopathia is platelet function disorder

Question 7

what are the 3 general causes of an acquired thombocytopenia?

Answer 7

increased platelet destruction (immune mediated thrombocytopenia, either idopathic or secondary)
increased platelet consumption (DIC or thrombosis)
decreased platelet production (bone marrow disease, drug induced, viral induced)

Question 8

true or false: primary or idipathic IMT is a diagnosis of exclusion

Answer 8

true

Question 9

increased platelet consumption can be caused by:

Answer 9

DIC, thrombosis
vasculitis

Question 10

myelophthisis and myelofibrosis can both cause

Answer 10

decreased bone marrow production (decrease platelets)

Question 11

the three most common causes of SEVERE thrombocytopenia (acquired) is:

Answer 11

• IMT, primary or secondary
• drug induced
• decreased BM production

Question 12

how does a congenital thrombocytopenia usually look on a blood smear?

Answer 12

large platelets and a decreased number of platelets

Question 13

do animals with congenital thrombocytopenia usually have hemorrhage?

Answer 13

no! you should suspect congenital thrombocytopenia if the animal has a persistent thrombocytopenia with no clinical signs!

Question 14

what is Von Willebrand’s Disease?

Answer 14

an extrinsic disorder of paltelet function caused by a deficinecy in vWF, and it is the most common hereditary bleeding disorder in dogs, pigs, and people

Question 15

what are the 3 types of von willebrand disease?

Answer 15

• type 1: not enough vWF but it works normally, most common form
• type 2: not enough vWF and it doesn’t work, severe but rare
• type 3: almost no vWF at all, severe but rare

Question 16

what is a BMBT and when would you use this?

Answer 16

buccal mucosal bleeding time, used to evaluate function of platelets when they are in NORMAL NUMBERS! DO NOT DO THIS IF THEY HAVE THROMBOCYTOPENIA!

Question 17

why would you want a BM aspirate for thrombocytopenia?

Answer 17

to distinguish between immune mediated and bone marrow disease

Question 18

what is the vWF: Ag assay?

Answer 18

von willebrand factor antigen assay which can evaluate vWF deficiency/disease.

Question 19

8 yo male stafford bull terrier, mild decrease in activity, petechail hemorrhages in mucus membranes. he has a marked/very severe thrombocytopenia, and his blood smear shows the occasional polychromatophil and metarubricyte.

Answer 19

• could be desruction, increased consumption, or decreased production
• IMT considering the platelet count is SO LOW!

Question 20

9 yo FS pitbull, lethargy, inappetence, fever. mild left shift with mild toxic change, moderate thrombocytopenia with giant platelets present on blood smear. there seems to be an organism inside a neutrophil on the smear

Answer 20

rickettsial bacterial infection

Question 21

2 yo F doberman, continuous vaginal bleeding since giving birth 8 weeks ago, skin rash that bleeds frequently. the RBCs, WBCs, and thrombogram are all normal…hmmm that’s sus

Answer 21

concern for thrombopathia, consider doing a BMBT test, it’s probs vWD