Disorders of Coagulation Flashcards
what are the four rule outs for thrombocytopenia?
consumption
destruction
production
sequestration
what are the spontaneous clinical signs of a problem with clotting?
petechiation
ecchymosis
epitaxis
GI hemorrhage
hematuria
what can you use to assess platelet function?
platelet aggregometry: not clinically available
buccal mucosal bleeding time
difficult to do
what are normal platelet numbers?
200,000-500,000/microL
spontaneous bleeding is rare if platelets are above ____________________
40,000/microL
how many platelets per high powered field is equal to about 15,000/microL?
one
what is buccal mucosal bleeding time prolonged with?
moderate thrombocytopenia
thrombocytopathia
von willebrand’s disease
what can lead to loss of platelets and thrombocytopenia?
bleeding
thrombosis
sequestration- trapped
what can cause destruction of platelets?
immune mediated thrombocytopenia
how common is immune mediated thrombocytopenia?
common
what can be seen on physical exam to show spontaneous bleeding?
petechiation, ecchymosis
epistaxis
GI hemorrhage
hematuria
ocular hemorrhage
what can be seen on a CBC with immune mediated thrombocytopenia?
severe thrombocytopenia- <15,000/microL
regenerative anemia
leukocytosis- inflammatory state
when should you be suspicious of a platelet function defect?
young dogs
platelet type bleeding
what is the most common inherited bleeding disorder?
von willebrand disease
what can you give to increase von willebrand factor release?
DDAVP (desmopressin)
what do you see with secondary hemostatic problems?
cavitary bleeding
hematomas
respiratory: hemoptysos
GI: hematemesis
when do PT/aPTT become prolonged?
> 75% of factors lost
if you have a prolonged PT and normal aPTT, what could be the problem?
factor VII deficiency
which factors are implicated in hemophilia?
factor VIII: A
factor IX: B
how is hemophilia transmitted?
sex linked recessive
more common in males
what can you give for excessive fibrinolysis?
aminocaproic acid
what makes up virchow’s triad?
endothelial damage
hypercoagulability
turbulent blood flow/stasis
what diseases are associated with hypercoagulability?
systemic inflammation
loss of endogenous anticoagulants
iatrogenic: corticosteroid use
neoplasia
what are some things that cause changes in blood flow?
cardiac disease in cats
immobility or paralysis
compression of vessel by mass
organ torsion: vascular torsion
how can we diagnose thrombosis?
index of suspicion:
underlying disease
physical exam
imaging
why do we not use thrombolytics that much?
can result in bleeding
what is disseminated intravascular coagulation?
coagulopathy associated with severe disease
mixed thrombosis and bleeding
what is secondary hemostasis?
fibrin clot
what is primary hemostasis?
platelet plug
what happens in excessive bleeding?
decreased platelet numbers and function
decreased clotting factors
what is an inherited disorder of primary hemostasis?
von willebrand’s disease
how many platelets per high powered field are normal?
8-15
what does buccal mucosal bleeding time assess?
platelet adhesion and aggregation
what can cause decreased production of platelets?
bone marrow disease: aplastic anemia, myelofibrosis, neoplasia
drugs, toxins
radiation therapy
what is directed against platelets in primary immune mediated thrombocytopenia?
autoantibodies
are females or males more commonly impacted by ITP?
females
how long does it take to respond to immunosuppression with prednisone?
4-6 days
what does vincristine do?
increases platelet production by megakaryocytes
more rapid platelet count response
what can cause acquired thrombocytopathia?
FIP
hyperglobulinemia
drug induced
uremia
hypo/hyperthermia
sepsis
what is impaired in von willebrand’s disease?
von willebrand factor mediated platelet adhesion
what is von willebrand factor?
major binding protein of platelet
stored in platelets and endothelial cells
bound to factor VIII
mediates contact of platelets with extracellular matrix
how many types of von willebrand disease are there?
three
I, II, III
what does DDAVP do?
stimulates von willebrand factor to release from endothelium
what are the types of cavitary bleeding?
hemathrosis
hemothorax
hemoabdomen
if there is a deficiency in factors IX and VIII, what is seen on PT/aPTT?
normal PT
elevated PTT
which animals are symptomatic for hemophilia?
homozygotes
what can lead to loss of endogenous anticoagulants?
PLN
PLE
what drugs can cause hypercoagulability?
corticosteroids
where can venous thrombi occur?
lungs- PTE (pulmonary thromboembolism)
legs- DVT (deep vein thrombosis)
portal vein- PVT (portal vein thrombosis)
what triggers microvascular coagulation in disseminated intravascular coagulation?
systemic inflammation
what becomes depleted in disseminated intravascular coagulation?
endogenous anticoagulants
clotting factors
