Considerations for Acquired and Inherited Blood Disorders
Course Number: 685
Course Contents
Von Willebrand Disease
Von Willebrand disease results from inherited defects in the structure, function and/or concentration of von Willebrand factor (vWF), a central component of hemostasis. In primary hemostasis, vWF serves as the initial critical bridge between circulating platelets and the injured blood vessel wall, mediates platelet adhesion to injured blood vessel sites, and promotes platelet aggregation at sites of vessel injury. Within secondary hemostasis, vWF acts as a stabilizer of coagulation FVIII in circulation, protects circulating FVIII from inactivation or degradation, and increases the half-life of FVIII from < 1hour to 8-12 hours. When bound to vWF, FVIII may localize to cells and/or sites where it can participate in coagulation.
There are several different types of vWD, responding to different treatment modalities. Figure 4 demonstrates the types and subclassifications of vWD, the severity level, molecular characteristics, and inheritance patterns. vWD Type 1 is by far the most common presentation of the condition. And as with hemophilia A and B, treatment planning and management for all cases of patients with vWD, must include consultation with the patient’s hematologist/HTC to determine the hemostatic treatment plan in order to enable a successful procedure and minimize bleeding risk.
Figure 4. vWD: Types and Classifications of Severity
| Type | % Present within Total Bleeding Disorder* | Molecular Characteristics | Inheritance |
|---|---|---|---|
| vWD Type 1 (mild) | 78% | Partial Quantitative vWF deficiency | Autosomal dominant, incomplete penetrance |
| vWD Type 2A (moderate) | 4% | Qualitative defect, decreased vWF-dependent platelet adhesion | Usually autosomal dominant |
| vWD Type 2B (moderate) | 2% | Qualitative defect, abnormal affinity for platelet glycoprotein (GP-Ib) | Autosomal dominant |
| vWD Type 2M (moderate) | 2% | Qualitative defect, decreased vWF-platelet interaction | Autosomal dominant |
| vWD Type 2N (moderate) | 0.7% | Qualitative defect; decreased vWF-factor VIII binding capacity | Autosomal recessive |
| vWD Type 3 (severe) | 1.5% | Severe quantitative reduction or absence of vWF | Autosomal recessive (or codominant) |
*Data reported by HTCs to CDC from 2012-2023. Missing percentages are comprised of individuals reported with a missing or unknown vWD diagnosis.
Patients with bleeding disorders will present with unique types and frequency of bleeds. Bleeds can occur internally, into joints and muscles, or externally, from mucosal surfaces (nose bleeds, menses), minor cuts, dental procedures, or injuries. Joint bleeding may start as tingling or warm sensation, progressing to severe pain and joint swelling. The joint will stiffen, and it may take several weeks for the joint to recover function. Joint bleeding tends to occur in the same “target” joint, and joint damage and fibrosis will occur with repeated joint bleeds. Internal bleeding may cause stroke-like symptoms if it occurs in the brain, or cause severe abdominal pain, vomiting of dark brown material or dark stools if it occurs in the abdomen. The frequency in which the patient bleeds and the severity of the bleed is dependent upon the amount and function of clotting factor(s) the patient produces naturally.24vWD, unlike hemophilia, is a condition that may be first recognized by a dental provider. Primary symptoms include epistaxis (nosebleeds), and mucosal bleeds inclusive of the gingival tissues. Any suspicion of a bleeding disorder must be communicated with the patient’s primary care provider for further evaluation. Figure 5 highlights the types of bleeds associated with hemophilia A, vWD, along with characteristics and special considerations.