Platelets Flashcards
Where is Tpo produced?
Tpo- thrombopoietin
pdx constantly by:
hepatocytes
renal tubular epithelium
BM stromal cells
How is Tpo cleared?
receptor uptake and destruction by platelets and MEgaK
Inverse relationship with paltelets/megaK
Which cytokine can induce hepatocyte pdx of Tpo?
IL-6
What mediates platelet adhesion specifically?
vWF
Factor 5 and 9
platelet receptor Gp-1b
How do platelets bind fibrinogen?
via Receptor Gp2b-3a
What color tube is used to assess platelets?
EDTA puprle top tube
What can cause a thrombocytopenia?
lack of pdx
increased desctruction
increased consumption
sequestration
massive external hemorrhage
What will cause a thrombocytosis?
chronic bleeding
iron def
inflammation
neoplasia
mega K neoplasia
cushings
T/F vWF disease is a coagulopathy
FALSE
What is vWF disease?
Defect in vWF
improper platelet adhesion/aggregation
MOST common inherited blood disorder in dogs
causes bleesing/petechia because cannot resist shear forces, platelet count is NORMAL
vWF Disease Type 1
Autosomal dominant/variable penetrance
mild affected dogs- no bleeding
vWF Type 2
Autosomal recessive
severe form is uncommon
very low levels of vWF in plasma
vWF Type 3
Severe form
autosomal recessive
Absence of all vWF
Clinical signs vWF disease:
mild to severe mucosal bleeding
epistaxis, GI hemmorrhage, cutaneous bleeding
hemoarthrosis
petechia
What test results indicate vWF?
PT, PTT, FIbrinogen, Plt all w/in Normal Limits
increased Buccosal Bleeding Time (good screening test)
