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Von Willebrand Factor
Aka: Von Willebrand Factor, VWF, Von Willebrand Factor Antigen, Von Willebrand Factor Ristocetin Cofactor Activity, VWF:Ag, VWF:RCo
- See Also
- Von Willebrand Deficiency
- Bleeding Disorder
- Physiology
- Von Willebrand Factor synthesis
- Vascular endothelium
- Megakaryocytes
- Von Willebrand Factor release
- Platelet activation
- Endothelial cells
- Von Willebrand Factor activity
- Binds factor VIII in circulation (prolongs Factor VIII half-life)
- Releases factor VIII in response to bleeding
- Factor VIII in turn is a Cofactor in the conversion of Factor IX to IXa in the initrinsic Clotting Pathway to form thrombin
- Bridges exposed collagen and platelets when vascular injury occurs
- Von Willebrand Factor mediates platelet adhesion
- Von Willebrand Factor is a large protein that binds damaged vasculature and traps, binds platelets to form a platelet plug
- Analogous to 6-pack plastic ring holder that traps wildlife
- Von Willebrand Factor deficiency
- Results in delayed platelet plug formation
- Results in mucocutaneous bleeding
- Labs
- Normal VWF range: 50-200 IU/dl
- Causes: Decreased VWF Levels or function
- Von Willebrand Deficiency
- Type O Blood (25% lower VWF than other blood types)
- Acquired Von Willebrands Deficiency
- Hypothyroidism (causes decreased VWF Synthesis)
- Wilms Tumor and lymphoproliferative disorders are associated with tumor cell binding to VWF resulting in VWF Deficiency
- Conditions with antibodies to VWF
- Lymphoproliferative disorders
- Monoclonal Gammopathy
- Systemic Lupus Erythematosus
- Conditions that alter VWF conformation via shearing resulting in increased proteolysis
- Ventricular Septal Defect
- Aortic Stenosis
- Hypertrophic Cardiomyopathy
- Primary Pulmonary Hypertension
- Left Ventricular Assist Device
- Conditions with significant Thrombocythemia
- Essential Thrombocythemia
- Polycythemia Vera
- Myeloproliferative disorders
- Medications
- Ciprofloxacin
- Valproic Acid
- Griseofulvin
- References
- Kumar (2002) Mayo Clin Proc 77(2): 181-7 [PubMed]
- Causes: Falsely increased VWF Levels
- Inflammatory Conditions
- Pregnancy