Blood Flashcards
What is Type 1 Von Willebrand disease characterized by?
Presence of all multimers but in reduced concentrations
Bleeding precipitated by surgery, trauma, or concomitant hemostatic defect
Which dog breeds are overrepresented in Type 1 Von Willebrand disease?
- Doberman Pinschers
- Standard Poodles
- Shetland Sheepdogs
- German Shepherd Dogs
- Airedale Terriers
These breeds have a higher incidence of Type 1.
What characterizes Type 2 Von Willebrand disease?
Disproportionate loss of high-molecular weight multimers
This type is associated with severe bleeding.
What is the hallmark of Type 3 Von Willebrand disease?
Almost complete absence of vWF (<0.1%)
This is the most severe form with life-threatening hemorrhage, often occurring within the first year of life.
True or False: Type 1 Von Willebrand disease is the most common type.
True
It is the most frequently occurring form of the disease.
Fill in the blank: Type 3 Von Willebrand disease is characterized by _______.
[almost complete absence of vWF (<0.1%)]
What platelet count is at risk for spontaneous hemorrhage?
50k
A platelet count below 50,000 cells per microliter increases the risk for spontaneous bleeding.
Formula to estimate total platelet count per hpf?
Avg Number/hpf x 15,000
This formula is used to estimate the total platelet count from a microscopic examination.
What is the normal range for Buccal Mucosal Bleeding Time?
<3 minutes
A bleeding time of less than 3 minutes is considered normal.
Which conditions can prolong Buccal Mucosal Bleeding Time?
- Thrombocytopenia
- Thrombopathia
- Vasculopathy (non-specific)
These conditions affect the ability of blood to clot properly, leading to prolonged bleeding times.
What do Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT) test for?
PT -> Extrinsic and/or common pathway
APTT -> Intrinsic and/or common pathway
These tests assess different pathways of the coagulation cascade.
What percentage decrease in a single factor can lead to prolongation in PT or APTT?
25 to 30%
A decrease of this magnitude indicates potential bleeding disorders.
What condition is the PT particularly sensitive to?
- vitamin K deficiency
- liver disease
- deficiencies in clotting factors like VII, X, V, and II
Due to the short half-life of factor VII, PT is affected quickly by vitamin K status.
What does Activated Clotting Time (ACT) evaluate?
Intrinsic and common pathways
ACT is used to monitor anticoagulation therapy and surgical bleeding risks.
How does the sensitivity of ACT compare to APTT?
Less sensitive
ACT is not as responsive as APTT in detecting minor coagulation issues.
What are Fibrin Split Products generated from?
When plasmin lyses fibrinogen, soluble fibrin, or cross-linked fibrin
This process indicates increased fibrinolysis in the body.
What do elevated concentrations of Fibrin Split Products indicate?
A fibrin degradation product (FDP), also known as a fibrin split product, is a small protein fragment that remains in the bloodstream after a blood clot dissolves, essentially a byproduct of the body breaking down a clot through a process called fibrinolysis; elevated levels of FDPs can indicate a potential clotting disorder or excessive clot breakdown.
Increased fibrinolysis and/or fibrinogenolysis
While they may be elevated in DIC, they are not specific to it.
What are d-Dimers a specific degradation product of?
Cross-linked fibrin
d-Dimers are particularly useful in diagnosing thrombotic conditions. Cross-linked fibrin is a protein polymer that forms clots and stabilizes platelet plugs. It’s created when activated coagulation factor XIII (FXIIIa) cross-links fibrin molecules.
What conditions are d-Dimers sensitive indicators of?
- Disseminated intravascular coagulation
- Thromboembolism
d-Dimers are more sensitive to thrombosis than fibrin split products.
What is the endpoint of all clotting assays?
Fibrin clot
The formation of a fibrin clot is the final step in the coagulation cascade.
At level concentration does fibrinogen typically become prolong on test?
<50 to 100 mg/dL
Significant prolongation of clotting tests usually occurs only after fibrinogen levels drop below this range.
What role does fibrinogen play during inflammation?
Elevated concentrations occur with inflammation
Fibrinogen is an acute phase protein and can reflect inflammatory states.
What do Viscoelastic Testing methods like Thromboelastography (TEG) and Rotational Thromboelastometry (ROTEM) assess?
the hemostatic process
Providing a real-time, holistic view of clot formation, strength, and dissolution in whole blood.
These tests evaluate the interplay between plasma and cellular components in coagulation.
What is edema?
Presence of abnormally large amounts of fluid in the intercellular tissue spaces of the body