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VON WILLEBRAND DISEASE

An Introduction to the Basics

Complete on-line presentation– 1 CEU Credit

AHF®, INC. – The Hemophilia Disease Management Company provides a full line of clotting medications, supplies, and ancillaries to families who are on home infusion programs.  Bleeding disorders are our only business and we have provided uninterrupted services to families and medical institutions since 1989.

AHF sponsors this presentation to improve services to individuals and families living with bleeding disorders.   One CEU (Continuing Education Unit) is available from CCMC (Commission for Case Managers Certification) for this course.  In order to obtain credit, you will need to read the attached course presentation and then complete the CEU evaluation.  The completed evaluation form will need to be returned to the address indicated below.

vWd

Von Willebrand disease (vWd) is characterized by the inability of the blood to clot normally. Blood is a fluid carried through the body in tubes called arteries, veins, and capillaries. When a tube is injured, a small hole forms, letting blood flow out. Stopping the flow of blood, or clotting, is necessary.

Blood clotting is a process that requires the following three steps to be successful.

    1. Vasoconstriction - the blood vessel narrows and slows the passage of blood from the hole
    2. Plug - platelets rush to the site, stick together, and act as a sticky cap or plug to stop the blood flowing– when von Willebrand factor (vWf) is missing from a person’s blood, the clotting problem starts here
    3. Clot - clotting factors and proteins in the blood, stop at the site, form a solid fibrin clot, and seal the hole, stopping the flow blood

If any of these steps is missed or does not work correctly, no clot is formed. The missing, defective, or poorly working element in vWd is a protein called vWf. VWf is a substance made by the lining cells of the blood vessels. VWf acts as a "catcher’s mitt" to bind platelets to the internal site of the "hole in the vessel" creating a plug.

A person with vWd may experience the inability to form a platelet plug from several kinds of events. Such events may include bleeding from injury, surgery, or from a spontaneous bleed. VWf also carries and protects Factor VIII (FVIII). Lack of FVIII will additionally cause a disruption in the entire clotting chain (cascade) making clot formation slow or unlikely. Without medical treatment to promote and sustain clotting, internal bleeding may continue and may cause long-term damage.

VWd occurs in 1 – 3% of the US population.

VWd is an equal opportunity disorder equally affecting women and men.

This means that approximately 2.6 million persons in the US have vWd.

 The Inheritance of vWd

The transmitter for vWd is on a non-sex linked chromosome. This means that a child of one gender is just as likely to receive this gene as a child of the other gender. vWd is transmitted when either parent passes on an altered gene to an unborn child. vWd is inherited in an autosomal dominant mode. This means that a parent who has vWd has a 50% chance of passing it to each child. If both parents are symptomatic for vWd, they have a 25% chance of having an affected child, a 50% chance of having a child who is a carrier, and 25% chance of having a child unaffected by vWd.

Some cases of vWd result from a spontaneous mutation during prenatal development. These individuals will then go on to carry the disorder to future generations. In rare cases, vWd is acquired during childbirth, drug-therapy, or autoimmune diseases such as rheumatoid arthritis, types of kidney failure, or certain cancers. Levels of severity range from low to moderate to severe.

Levels of severity are usually the same within a family, but in rare cases, may vary from one family member to another.

The Symptoms of vWd

Recurrent nose bleeds

Easy bruising

Heavy or prolonged menstrual flow

Bleeding from digestive or urinary tract

Unusual or excessive bleeding from mouth or gums

Unusual bleeding after surgery, dental procedures, and injury

Bleeds into joints, muscles, or the brain, though less common

Recurrent spontaneous bleeding anywhere, though less common

Testing for vWd to Measure Levels, Function, Severity, and Type

Levels can be mild, moderate, or severe.

Types include type 1 (comprising 70 – 80% of cases), type 2, and type 3 (rare and severe).

Type 1 is characterized by decreased vWf activity.

Type 2 is characterized by abnormal vWf.

Type 3 is characterized by no vWf at all.

Specialized labs are necessary, and many community labs are not equipped, to undertake diagnostic tests for vWd.

 Diagnostic testing includes:

Bleeding Time –minutes needed to stop a bleed from a small laceration made in the skin

Factor VIII: C –measures amount of factor VIII activity

VWf Antigen – measures amount of vWf

Ristocetin Cofactor Activity – measures vWf function

VWf Multimers – measures the structure of the vWf molecule

Platelet Function Tests – measures how well platelets work in the test tube

Test results are often not accurate. Tests may need to be repeated several times, over months, before a precise diagnosis can be confirmed. Test results may be affected by many variables in the patient as well as the lab technician.

 Results of diagnostic tests may be influenced by:

Menstrual cycle

Use of aspirin or non-steroidal anti-inflammatories

Cold environment

Birth control pills, hormone therapy, pregnancy, breast feeding, and childbirth

Exercise, stress, and crying

 Diagnosis of vWd

Diagnosis can be at birth (in families suspecting vWd). Diagnosis may also follow severe bleeding from accident, dental work, sports injury, or trauma. OBGYNs treating heavy menstrual bleeding or assessing excessive bleeding with childbirth may make a diagnosis of vWd.

 Common Misdiagnoses and Possible Results

Medical practitioners may fail to consider a bleeding disorder as an explanation when treating a symptomatic female patient. Some may be unfamiliar with bleeding disorders, unaware of available diagnostic tests, or deem tests unnecessary. Bleeding symptoms may be thought to be a result of other causes, for example:

A low platelet count may be considered the result of leukemia, autoimmunity, or other conditions.

Heavy menstrual bleeding may be seen as hormonal or gynecological.

Surgical solutions, such as hysterectomy, may be carried out unnecessarily as a result of misdiagnosis of a bleeding disorder.

Bleeding may persist and yet remain undiagnosed, presenting a risk of death in traumatic situations.

 Treatment for vWd

Mild bleeds may be treated with pressure. Often mild bleeds are self-limiting.

Commonly used medications for more severe bleeding include:

Hormones found in oral contraceptives administered intravenously, orally, topically, or by patch application can often be helpful in prevent bleeding.

Localized bleeding in the nose or mouth may be treated at the site with Thrombinar, Avitene, or Instat followed by a medication such as Amicar (aminocaprioc acid).

For more severe bleeds, DDAVP, a synthetic hormone that causes the body to release its own stores of vWf and FVIII, is successful in treating type 1. (Intravenous injection or nasal spray administers DDAVP.) Intermediate purity FVIII products can be used for vWf type 2 and 3 by intravenous injection. This acts as a replacement for the missing protein.

Recombinant and monoclonal FVIII products do not contain any vWf and cannot be used.

Although not a treatment, pregnancy may increase estrogen and, thereby, decrease the impact of vWd.

 AHF does not engage in the practice of medicine. Under no circumstance does AHF recommend a particular treatment or medication for a particular individual. In all cases, AHF recommends that a patient consult a physician or hemophilia treatment center before beginning a specific treatment.

Setting the Standard of Care for People with Bleeding Disorders

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 VON WILLEBRAND DISEASE  - INTRODUCTION TO THE BASICS - 1 CEU

EVALUATION – 1 Credit

It has been our pleasure to share our knowledge and understanding of von Willebrand disease. We ask that you please take a moment to complete the questions below. Your comments are very valuable to us. This evaluation is required by CCMC to fulfill CEU obligations. Please print out this form and return it to AHF, Inc., 31 Moody Road, P.O.B 985, Enfield, CT 06083. Thank you very much for your cooperation.

                                                                    YES     NO

Did you find the overview informative?            ___      ___

Name 3 characterists of vWd.

 

How is vWd inherited in families?  Are there spontaneous mutations with no family history?  How many people in the U.S. have vWd?

 

What factors are missing from the blood in vWd and why does the blood not clot normally?

 

Name the different kinds of vWd and the 3 different levels of severity of vWd.

 

Name 5 known symptoms of vWd that indicate that someone might have the disease. 

Name 3 indicators that someone with vWd is having a bleed.

 

How is vWd medically detected?  What kinds of tests are used to determine if a person has vWd and what kind of vWd he/she might have?  How effective are these tests?

 

Why might vWd be misdiagnosed?  What are some of the possible results of misdiagnosis?

 

Did the information meet your expectations?        ___     ___

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AHF®, Inc. does not prescribe medications or give medical recommendations to individuals. AHF does not endorse or refer any particular individual to a specific HTC or medical provider.  It is best to obtain medical recommendations from your physician and/or your HTC.