Diagnosing VWD

Von Willebrand Disease (VWD) is the most common inherited bleeding disorder, occurring in about 1 in every 100 people⁴. Whereas hemophilia occurs mostly in males, VWD affects both males and females.

The disease is characterized by easy bruising and excessive mucosal bleeding, such as heavy menstrual periods and bleeding from the mouth or nose. VWD is caused by a deficiency or abnormality of von Willebrand factor (VWF), a protein in the blood that is instrumental in promoting platelet adhesion to areas of blood vessel injury.

To diagnose VWD, your doctor should consider:

Your health history — When did you first start bleeding excessively? How long does the bleeding last? When does the bleeding start and where and how often do you bleed?
Family history — VWD is an inherited bleeding disorder,^* so your doctor may ask about bleeding patterns of family members
Lab tests — Blood samples may show if you have VWD and if so, what type

^*In most cases, a person inherits VWD from a parent; in rare cases, VWD can be acquired¹

VWD can be difficult to diagnose. Here’s why:

Symptoms of VWD can be very mild, even unnoticeable.²

Mild symptoms of VWD may be mistaken for other illnesses
People with VWD may not even suspect they have the disease and may never get tested
Some find out they have VWD only after they’ve had heavy bleeding following an accident or dental surgery
In women, menorrhagia (heavy menstrual bleeding) may be the only manifestation of VWD

The amount of von Willebrand factor in someone’s blood can vary at different times.

Certain situations or conditions (stress, pregnancy, infection, etc.) can cause the amount of VWF to temporarily increase,³ making it hard for doctors to make a specific diagnosis
This means blood tests would need to be taken more than once

Testing for VWD is complicated.

Testing for VWD involves many different kinds of blood tests.
If you believe you have VWD, it is important to go to a hemophilia treatment center or to a hematologist, (a doctor who specializes in testing for and treating bleeding disorders)

Should you get tested for VWD?
If you have mild symptoms (easy bruising, nosebleeds, etc.), you should get tested for VWD. Why? If you are in an accident or you need surgery, you may experience heavy and prolonged bleeding. To give you the proper treatment, your doctor would need to know what’s causing the extra bleeding—the VWD or the injury itself.

In order to diagnose VWD and select the appropriate therapeutic option, your doctor must determine the specific disease type and subtype. Doing so could require several specific blood tests, which may include one or more of the following:

VWF activity (VWF:ristocetin cofactor, or VWF:Rco) – provides a measurement of VWF function
VWF multimer assay – analyzes the quality and provides a measurement of VWF multimers; this is an essential test for determining subtype.
FVIII clotting activity (FVIII:C) – determines the degree of FVIII activity.
VWF antigen (VWF:Ag) – measures the quantity of VWF.
Ristocetin-induced platelet aggregation (RIPA) – provides a measurement of VWF function.
Platelet function analyzer 100 (PFA-100) – identifies the presence of VWD through primary hemostasis simulation.

Repeated laboratory tests are required to confirm or rule out a diagnosis of VWD. This is because VWF levels can fluctuate due to exercise, stress, recent surgery, infection, hormone therapy, medications, and pregnancy, childbirth, and breast feeding. The patient’s blood type can also complicate diagnosis of VWD as blood group O individuals have plasma levels of VWF 20% to 25% lower than non-O individuals⁵.

Important Safety Information

Humate-P is indicated for treatment and prevention of bleeding in adult patients with hemophilia A (classical hemophilia). Humate-P is also indicated in adult and pediatric patients with von Willebrand disease (VWD) for (1) treatment of spontaneous and trauma-induced bleeding episodes, and (2) prevention of excessive bleeding during and after surgery. This applies to patients with severe VWD, and patients with mild and moderate VWD for whom use of desmopressin is known or suspected to be inadequate. Humate-P is not indicated for the prophylaxis of spontaneous bleeding episodes.

Humate-P is contraindicated in individuals with a history of anaphylactic or severe systemic response to antihemophilic factor or von Willebrand factor preparations.

Monitor for intravascular hemolysis and decreasing hematocrit values in patients with A, B, and AB blood groups who are receiving large or frequent doses. Also monitor VWF:RCo and FVIII levels in VWD patients, especially those undergoing surgery.

Thromboembolic events have been reported in VWD patients receiving coagulation factor replacement. Caution should be exercised and antithrombotic measures considered, particularly in patients with known risk factors for thrombosis.

Humate-P is derived from human plasma. The risk of transmission of infectious agents, including viruses and, theoretically, the Creutzfeldt-Jakob disease (CJD) agent, cannot be completely eliminated.

In patients receiving Humate-P in clinical studies for treatment of VWD, the most commonly reported adverse reactions observed by >5% of subjects are allergic-anaphylactic reactions, including urticaria (hives), chest tightness, rash, pruritus (itching), and edema (swelling). For patients undergoing surgery, the most common adverse reactions are postoperative wound or injection-site bleeding, and epistaxis (nosebleed).

Please see full prescribing information.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.

References

The “Other” Bleeding Disorder. Available at:http://www.haemophilia.org.za/Vonwil2.htm. Accessed June 20, 2006.
Montgomery RR, Hilgartner MW. Understanding von Willebrand Disease. The National Hemophilia Foundation; 1991.
National Hemophilia Foundation, Bleeding Disorders Information Center/von Willebrand disease. Available at: http://www.hemophilia.org/bdi/bdi_types3.htm. Accessed June 20, 2006.
Rodeghiero F, Castaman G, Dini E. Epidemiological investigation of the prevalance of von Willebrand’s disease. Blood. 1987;69:454-459.
Lillicrap D. The basic science, diagnosis and clinical management of von Willebrand disease, in Treatment of Hemophilia (World Federation of Hemophilia, publishers). 2004;35:1-11.