von Willebrand's Disease (VWD) is the most
common form of hemophilia (bleeding disorder) in humans. Luckily, it is also the mildest.
It is an inherited shortage of a protein (von Willebrand's protein) necessary for platelet
adhesion to injured blood vessels, a first step in blood clot formation. Most individuals
have a mild form of the disease with minimal bleeding. A few individuals have a severe
form more similar to other hemophilia’s with respect to bleeding.
In the mild/moderate form, the inheritance pattern of VWD is such that usually
one parent has as history of bleeding symptoms and approximately 50% of offspring are
affected, males and females equally. The severe form may be inherited in a way where both
parents are "silent carriers" and there is only a 25% chance the child will have
the disease.
Because platelets are primarily responsible for stopping bleeding on mucous
membranes, people with VWD may have frequent nose bleeds, stomach or intestinal bleeding.
A history of easy bruising, heavy menstrual periods, or increased bleeding after surgery
or dental work may also be a clue. In the more severe forms, muscle and joint bleeding may
occur.
VWD can only be diagnosed with blood tests. Treatment involves medication
and/or blood products used to prevent or arrest bleeding.
- DDAVP (Stimate) is a synthetic hormone given intravenously
to mobilize preexisting stores of the von Willebrand's protein from storage sites in the body. This ultimately
raises the von Willebrand’s protein level in the blood two-three fold in some
patients.
A test dose of DDAVP is usually given when a patient is first diagnosed with VWB to
test its efficacy in that individual.
- Cryoprecipitate is a blood product used when DDAVP is not
indicated or doesn’t work. It is contains many clotting proteins, including von Willebrand’s protein, derived
from donated blood.
- More recently, a specially
purified factor VIII concentrate, heat pasteurized
(Humate-P or Koate HS) may be used in place of cryoprecipitate in people with severe
VWD.
- Aminocaproic acid
(Amicar) can be used orally in bleeding involving the
nose, mouth and
other mucous membranes. Amicar helps to stabilize blood
Pretreatment with one of the above is
generally necessary for all surgeries and invasive procedures including dental work
(except cleanings), suturing, and significant trauma with subsequent bleeding.
Other recommendations for individuals with VWD include yearly visits with a
Hematologist and dental cleaning on a bi-yearly basis. Childhood immunizations should be
given subcutaneously instead of intramuscularly. Aspirin and salicylate containing
products and nonsteroidal anti-inflammatories (Motrin, Advil, Alleve) should be avoided.
All patients are encouraged to wear a MedicAlert bracelet. Contact sports such as hockey,
soccer and football are generally not encouraged. |
