VON WILLEBRAND DISEASE
An Introduction to
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.
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.
- Vasoconstriction - the blood
vessel narrows and slows the passage of blood from the hole
- 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
- 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.
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.
Recurrent nose bleeds
Heavy or prolonged menstrual
Bleeding from digestive or
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
bleeding anywhere, though less common
vWd to Measure Levels, Function, Severity, and Type
Levels can be mild, moderate,
Types include type 1
(comprising 70 – 80% of cases), type 2, and type 3 (rare and
Type 1 is characterized by
decreased vWf activity.
Type 2 is characterized by
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.
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
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:
Use of aspirin or
Birth control pills, hormone
therapy, pregnancy, breast feeding, and childbirth
Exercise, stress, and crying
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.
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
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
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
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
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
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.
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?
Phone and e-mail address
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