17: Von Willebrand’s Disease: Assessment, Analysis, and Associated Dental Management Guidelines

17

Von Willebrand’s Disease: Assessment, Analysis, and Associated Dental Management Guidelines

The vWF gene is responsible for the making of von Willebrand factor, which is made within endothelial cells of blood vessels and the bone marrow cells. The factor is made of several identical subunits and mutations in the vWF gene, which results in the different types of von Willebrand Disease (vWD). Von Willebrand Disease (vWD), hemophilia A, and hemophilia B are the three leading inherited bleeding disorders, and vWD is the most common of the three. Von Willebrand’s Disease (vWD) affects both males and females.

As discussed in the previous chapter, when injury occurs, the blood vessels at the injured site constrict. This attracts the circulating platelets to the site of injury. The platelets link with each other and form the platelet plug. Von Willebrand’s Factor (vWF) thus plays a very important role in primary hemostasis because it enhances platelet cohesiveness. Von Willebrand Factor also helps transport and stabilizes Factor VIIIc (VIII clotting) in the circulation. Factor VIIIc participates in the clotting cascade.

Depending on the severity of the disease in patients with vWD, the half-life and activity of Factor VIIIc is decreased. The PTT will be prolonged in such cases. Therefore, patients with von Willebrand’s disease can present with problems associated with either primary or secondary hemostasis, or both.

TYPES OF VON WILLEBRAND’S DISEASE

Type 1 vWD

Type 1 vWD is the most common and mildest form of the disease; 85% of patients diagnosed with vWD have type 1 vWD. It is least symptomatic in most patients, but if symptomatic, it usually presents as nosebleeds, easy bruising, or menorrhagia (heavy menstrual periods). However, some cases may present with significant bleeding.

The quality of the vWF is normal. The amount of von Willebrand’s Factor (vWF) in the blood is reduced, but adequate amounts exist in the endothelial stores. Thus, it is a quantitative defect. These patients are usually asymptomatic but can have the immediate type of bleeding and significant oozing beyond 24 hours following an extraction.

Type 2 vWD

Type 2 vWD accounts for about 20–30% of cases. Mutations that disrupt the function of the von Willebrand factor cause the four subtypes of type 2 von Willebrand disease. These mutations can disrupt the factor’s ability to form a blood clot. There are normal levels of vWF but the multimers are structurally abnormal. Thus, the quality of the vWF is affected, both in the blood and at the storage sites. There are four subtypes that exist: 2A, 2B, 2M, and 2N. Type 2B is also associated with a decreased platelet count or thrombocytopenia.

Type 3 vWD

Type 3 is the most severe form of von Willebrand disease. It is associated with a complete a/>

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Jan 4, 2015 | Posted by in General Dentistry | Comments Off on 17: Von Willebrand’s Disease: Assessment, Analysis, and Associated Dental Management Guidelines
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