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Questions and Answers
Which of the following laboratory findings is characteristic of von Willebrand disease (vWD)?
Which of the following laboratory findings is characteristic of von Willebrand disease (vWD)?
In which type of von Willebrand disease is a decreased platelet count typically observed?
In which type of von Willebrand disease is a decreased platelet count typically observed?
What is the expected prothrombin time (PT) result in a patient with von Willebrand disease (vWD)?
What is the expected prothrombin time (PT) result in a patient with von Willebrand disease (vWD)?
Which assay is crucial for differentiating between various subtypes of von Willebrand disease (vWD)?
Which assay is crucial for differentiating between various subtypes of von Willebrand disease (vWD)?
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What is the expected platelet function in a patient with Hemophilia A or B?
What is the expected platelet function in a patient with Hemophilia A or B?
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What is the primary role of von Willebrand factor (VWF) in the context of hemostasis?
What is the primary role of von Willebrand factor (VWF) in the context of hemostasis?
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Which type of von Willebrand disease (VWD) is characterized by a partial quantitative deficiency of VWF?
Which type of von Willebrand disease (VWD) is characterized by a partial quantitative deficiency of VWF?
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In Type 1 von Willebrand disease, what is typically observed in laboratory tests?
In Type 1 von Willebrand disease, what is typically observed in laboratory tests?
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Which type of von Willebrand disease (VWD) is considered the most severe form?
Which type of von Willebrand disease (VWD) is considered the most severe form?
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Which of the following is a characteristic of Type 3 von Willebrand disease?
Which of the following is a characteristic of Type 3 von Willebrand disease?
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In type 2N von Willebrand disease, what specific defect is observed?
In type 2N von Willebrand disease, what specific defect is observed?
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Which type of von Willebrand Disease has decreased affinity for GP1b?
Which type of von Willebrand Disease has decreased affinity for GP1b?
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A patient is suspected of having a bleeding disorder. Initial tests reveal normal levels of Factor VIII but prolonged bleeding time. Which subtype of von Willebrand disease should be suspected?
A patient is suspected of having a bleeding disorder. Initial tests reveal normal levels of Factor VIII but prolonged bleeding time. Which subtype of von Willebrand disease should be suspected?
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Flashcards
Type 2 VWD
Type 2 VWD
A subtype of von Willebrand disease characterized by defective platelet aggregation with ristocetin and often low levels of VWF.
Bleeding Time
Bleeding Time
A laboratory test measuring how long it takes for bleeding to stop, often prolonged in VWD.
Factor VIII Levels
Factor VIII Levels
Factor VIII is a blood-clotting protein; low levels indicate a risk for bleeding, particularly in hemophilia A and VWD.
APTT Prolongation
APTT Prolongation
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Defective Platelet Aggregation
Defective Platelet Aggregation
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von Willebrand Disease (VWD)
von Willebrand Disease (VWD)
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Von Willebrand Factor (VWF)
Von Willebrand Factor (VWF)
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Epistaxis
Epistaxis
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Menorrhagia
Menorrhagia
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Inheritance pattern of Type 1 VWD
Inheritance pattern of Type 1 VWD
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Study Notes
Von Willebrand Disease (VWD)
- VWD is a congenital bleeding disorder, the most common hereditary bleeding disorder affecting both sexes.
- It's characterized by a lifelong tendency towards easy bruising, frequent nosebleeds (epistaxis), and heavy menstrual bleeding (menorrhagia).
- Von Willebrand factor (VWF) acts as a carrier for factor VIII (FVIII) and is crucial for platelet adhesion and aggregation.
VWD Classification
- VWD is classified based on either reduced levels or abnormal function of VWF, stemming from a point mutation or major deletion.
- Quantitative VWD:
- Type 1: Partial VWF deficiency
- Type 3: Complete VWF deficiency
- Qualitative VWD:
- Type 2: Qualitative mutants of VWF (further categorized into subtypes 2A, 2B, 2M, and 2N)
Type 1 VWD
- This is the most common subtype (70-80% of cases).
- Characterized by a partial quantitative decrease in VWF and FVIII.
- Individuals often have mild symptoms.
- Inherited as an autosomal dominant trait.
- Lab findings: A proportional decrease in VWF activity, VWF antigen, and FVIII is observed.
Type 3 VWD
- The most severe form.
- Marked deficiency of both VWF and FVIII in the bloodstream.
- Absence of VWF from platelets and endothelial cells.
- Characterized by severe clinical bleeding.
Type 2 VWD
- Qualitative mutants of VWF.
- Classified further into four subtypes based on functional defects:
- 2A: Decreased affinity for GP1b
- 2B: Increased affinity for platelets leading to platelet aggregation
- 2M: Large multimers with decreased affinity for platelets
- 2N: Defective factor VIII binding site, decreased affinity for FVIII, but normal in other aspects (often mistaken for hemophilia)
Secondary Classification of Type 2 VWD
- A table classifying type 2 VWD subtypes further based on platelet-associated function, factor VIII binding capacity, and high MW VWF multimers.
Lab Investigations for VWD
- Bleeding time is often prolonged.
- Factor VIII levels are frequently low; if low, a factor VIII/VWF binding assay is performed.
- Activated Partial Thromboplastin Time (APTT) may be prolonged.
- VWF levels are typically low.
- Platelet aggregation with ristocetin (VWF:RCo) and other agents (ADP and thrombin) is often normal.
- Multimer analysis is used for subtype classification.
- Platelet count is usually normal, except in type 2B VWD.
Comparison of VWD with Hemophilia A and B
- Comparison table showing differences in inheritance, main sites of bleeding, platelet count, bleeding time, clotting factors, ristocetin-induced platelet aggregation, and other tests for VWD, Hemophilia A, and Factor IX deficiency.
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Description
This quiz covers the essentials of Von Willebrand Disease (VWD), a common hereditary bleeding disorder. It includes details on its classification, types, symptoms, and the role of Von Willebrand factor in the condition. Test your understanding of this important medical topic.
