Platelets and Coagulation- The essentials Flashcards
In what species are thrombocytes not nucleated cells?
Mammals
What protein stimulates the production of megakaryocytes and development of platelets
Thrombopoietin
What is the average platelet life span?
5-10 days
What are some potential challenges for a platelet analyser?
Struggle to separate especially if the erythrocytes are small and the platelets are large
What breed of dog has large platelets?
Cavalier King Charles Spaniel
What is Thrombocytosis?
Occurs when another disease/ condition causes you to have a high platelet count
What are some conditions that may cause you to have a high platelet count?
Inflammation
response to iron deficiency
recovery from previous thrombocytopenia
Response to epinephrin or exercise
What is Cytopenia?
Having low levels of different blood cells
What are some different ways cytopenia can occur?
Increased loss
Decreased production
Increased consumption
Sequestration
What are some ways thrombocytopenia can occur?
response to some drugs
spleen removing cells from circulation
What is the difference between primary and secondary IMHA?
Primary- where the immune system attacks its own red blood cells
Secondary- where an underlying disease modifies the red blood cells
What is disseminated intravascular coagulation?
abnormal blood clotting throughout the bodies vessels
What is envomation?
The injection of venom
What is haemostasis?
Balance between clot formation and clot breakdown
These processes are in continual balance
What is primary haemostasis?
Evaluation of the platelets
What is a coagulopathy?
A condition that affects how your blood clots
it can result in a lack of platelets/ a lack of functioning platelets
What is secondary haemostasis?
The formation of fibrin through the clotting cascade
What is primary haemostasis?
The initial response of the body to vascular injury and involves interactions between platelets
What kind of pathway is the PT pathway?
extrinsic
What kind of pathway is the APTT pathway?
intrinsic
Why cant you use the APTT Pathway testing for avians?
They do not have factor 12
What is fibrinolysis?
Breakdown of a clot
What kind of plasma is required to assess clotting factors?
citrate plasma
What are D-Dimers and FDP’s
evidence of?
Evidence of Clot breakdown
What is viscoelastic testing?
provides a full hemostasis overview from a patient whole blood sample
What kind of state cannot be identified on PT/ APTT testing
Hypercoagulable states
What are some platelet disorders that can be inherited?
Glanzmann’s thrombasthenia
vWD
What is type I disease?
all vWF multimers are present but proportionately low
What is type II disease?
deficiency of vWF multimers with high molecular weight
What is type III disease?
absence of all vWF multimers
What is vWD factor important for?
its important for platelet adhesion and aggregation, it competes with factor 7 for stabilisation
What is the clinical presentation of primary haemostasis/ decreased platelets
Haemorrage
e.g * Petechiae – 1-4mm –
* Epistaxis
* Haematuria
What is the clinical presentation of secondary haemostasis/ decreased clotting factors
- Ecchymoses
- Haematomas
- Haemorrhage into body cavities, joints
What is a D-Dimer
A fibrin degredation
evidence of clot degredation
Give an example of a coagulpathy
Von Willebrands disease
Whys hould you not use a glass tube for measuring clotting factors?
Glass surfaces will activate the clotting factors
What does the extrinsic coagulation pathway begin with?
Tissue factor
What is the extrinsic pathway also known as?
the PT pathway
What is the intrinsic pathway also known as?
the APTT pathway
What is type I vWF disease?
all multimers are present but proportionately low
What is type II vWF disease?
deficiency of vWF multimers with high molecular weight
What is type III vWF disease?
absence of all vWF multimers
At what magnification will platelets need to be identified at?
x100 oil immersion
Give some examples of things that can cause disseminated intravascular coagulation
- Envenomation
- Hepatic disease
- infection
- necrosis
- pancreatitis
How can you test the function of platelets in house?
buccal mucousal bleeding test
What causes platelet sequestration?
Platelets get stuck in the spleen
What causes platelet destruction?
immune-mediated thombocytopenia
What causes decreased production of platelets?
response to drugs or an infection
What causes platelet consumption?
coagulopathy, e.g DIC