Magazine article American Nurse Today

Von Willebrand Disease 101

Magazine article American Nurse Today

Von Willebrand Disease 101

Article excerpt

When looking back on nursing school, most nurses probably remember diagnosing themselves with the "disease of the day." Nursing students question every symptom and ailment they have ever experienced as they dive into the details of unfamiliar diseases. You may have even thought you had von Willebrand disease (VWD) when you first learned of it.

Whether or not you suspected you had VWD, you probably don't remember much about it and you might not have cared for anyone with the disease, since experts estimate that only about 1% of the population has the condition. But VWD is the most common inherited bleeding disorder, which means it's important for you to understand the basics of the disorder so you can deliver the care patients with VWD need.

Overview

Dr. Erik von Willebrand first described VWD in 1926. This congenital bleeding disorder is characterized by low or ineffective von Willebrand factor, which is essential for platelet adhesion and helps to transport factor VIII in the blood. VWD causes a variety of bleeding symptoms such as abnormal bruising, heavy menstrual periods, nosebleeds that are difficult to stop, mucosal bleeding, and abnormal bleeding after surgery or trauma. While VWD is not curable, it is treatable.

VWD can be inherited from either parent. Although it affects both men and women, women are diagnosed more frequently, most likely because of symptoms related to heavy menstrual periods. (See Types of VWD)

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Types of VWD

VWD occurs in three major types. Type 1, the most common, is
characterized by low levels of von Willebrand factor. People with type
1 VWD also may have low levels of factor VIII. Type 1 causes mild
symptoms.

People with type 2 VWD have a normal amount of VWF, but the factor
doesn't function properly. Type 2 VWD is broken down into subtypes
2A, 2B, 2M, and 2N. The defective clotting process differs in each
subtype, and each is caused by a different genetic mutation. Treatment
depends on the subtype, so proper diagnosis is essential. People with
type 2 VWD can experience mild to moderate bleeding problems.

Type 3 VWD is rare and usually only occurs in people who have two
parents with VWD. This type results in little or no von Willebrand
factor and low levels of factor VIII. Type 3 VWD is severe and
requires a more aggressive treatment plan. These patients must be
diligent in being aware of bleeding symptoms and get immediate
treatment when bleeding occurs.

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Diagnosis

There is no single test for VWD, which can make diagnosis challenging. The first step in evaluating a patient is to obtain a complete family history. Be aware that because of mild unnoticed symptoms, a family history of VWD or abnormal bleeding may not always be present.

Next, initial laboratory tests are done to eliminate other causes of abnormal bleeding. These tests include a complete blood count, activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen level, and platelet count.

If these tests fail to identify a cause for bleeding, additional testing is done. The tests more specific to VWD are von Willebrand factor antigen (VWF:Ag), von Willebrand factor ristocetin cofactor (VWF:RCo), and a factor VIII level. The VWF antigen test will show the amount of VWF in the blood. A level less than 30 IU/dl is definitive for VWD; however, a level between 30 IU/dl and 50 IU/dl also can be indicative. The VWF:RCo test indicates the functionality of VWF; that is, how well it is working.

A hematologist familiar with VWD must evaluate the patient's history and the results of all of these tests. Further testing may be required. For example, if VWD is confirmed, a multimeric test is done to determine which type of VWD is present. If a patient has a bleeding history and the VWD testing is negative, a platelet aggregation may be completed to explore a different diagnosis. Also, testing multiple times is recommended because of events that may alter levels temporarily such as medications, pregnancy, menstrual cycle, breastfeeding, recent surgery, or stress. …

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