Bleeding disorders are a
group of conditions that result when the blood cannot clot properly. In
normal clotting, platelets stick together and form a plug at the site
of an injured blood vessel. Proteins in the blood called clotting
factors then interact to form a fibrin clot, which holds the platelets
in place and allows healing to occur at the site of the injury while
preventing blood from escaping the blood vessel. While too much
clotting can lead to heart attack and stroke, the inability to form
clots can be very dangerous as well, as it can result in excessive
bleeding.
Hemophilia
is perhaps the most well-known bleeding disorder, although it is
relatively rare. It affects mostly males. Many more people are affected
by von Willebrand disease, the most common bleeding disorder in America.
Von Willebrand disease can affect both males and females. You can find
information on other bleeding disorders by following the links at the
bottom of this page.
Am I at Risk?
Bleeding disorders such as hemophilia and von
Willebrand disease result when the blood lacks certain clotting
factors. These diseases are almost always inherited, although in rare
cases they can develop later in life if the body forms antibodies that
fight against the blood’s natural clotting factors. Individuals and
pregnant women with a family history of bleeding disorders should talk
to their doctors about detection and treatment. Symptoms of bleeding
disorders may include:
- Easy bruising
- Bleeding gums
- Heavy bleeding from small cuts or dental work
- Unexplained nosebleeds
- Heavy menstrual bleeding
What Is Hemophilia and How Is It Treated?
Hemophilia is a rare, typically inherited, bleeding
disorder that can range from mild to severe, depending on how much
clotting factor is present in the blood. Hemophilia is classified as
Type A or Type B, based on which type of clotting factor is lacking
(factor VIII in Type A and factor IX in Type B). Hemophilia results
from a genetic defect found on the X chromosome. Women, who have two X
chromosomes, can pass the disease onto their sons but will be not be
affected by the disease unless both X chromosomes have the defective
gene; this is very rare. On the other hand, males, who have one X and
one Y chromosome, will be affected by hemophilia if their one X
chromosome has the defective gene.
Because blood does not clot properly without enough
clotting factor, any cut or injury carries the risk of excessive
bleeding. In addition, people with hemophilia may suffer from internal
bleeding that can damage joints, organs, and tissues over time.
In the past, people with
hemophilia were treated with transfusions of factor VIII obtained from
donor blood, but by the early 1980s these products were discovered to
be transmitting blood-borne viruses, including hepatitis and HIV.
Thanks to improved screening techniques, and a major breakthrough that
enabled scientists to create synthetic blood factors in the laboratory
by cloning the genes responsible for specific clotting factors, today’s
factor-replacement therapies are pure and much
safer than ever before.
What Is von Willebrand Disease and How Is It
Treated?
Von Willebrand disease is an inherited condition that
results when the blood lacks von Willebrand factor, a protein that
helps the blood to clot and also carries another clotting protein,
factor VIII. It is usually milder than hemophilia and can affect both
males and females. Von Willebrand disease is classified into three
different types (Types 1, 2, and 3), based on the levels of von
Willebrand factor and factor VIII activity in the blood. Type 1 is the
mildest and most common form; Type 3 is the most severe and least common
form.
With early diagnosis,
people with von Willebrand disease can lead normal, active lives.
People with mild cases may not require treatment, but should avoid
taking drugs that could aggravate bleeding, such as aspirin and
ibuprofen, without first consulting with a doctor. More serious cases
may be treated with drugs that increase the level of von Willebrand
factor in the blood or with infusions of blood factor concentrates. It
is important for people with von Willebrand disease to consult with
their doctors before having surgery, having dental work, or giving
birth, so that proper precautions can be taken to prevent excessive
bleeding. You may be referred to a hematologist, a doctor who
specializes in the treatment of blood disorders.
Where Can I Find More Information?
If you are interested in
learning more about blood diseases and disorders, here are a few other
resources that may be of some help:
Articles
From Hematology, the ASH Education Program Book
The American Society of Hematology (ASH) Education Book, updated
yearly by experts in the field, is a collection of articles about the
current treatment options available to patients. The articles are
categorized here by disease type. If you are interested in learning
more about a particular blood disease, we encourage you to share and
discuss these articles with your doctor.
Results of
Clinical Studies Published in Blood
Search Blood, the official journal of ASH, for the
results of the latest blood research. While recent articles generally
require a subscriber login, patients interested in viewing an
access-controlled article in Blood may obtain a copy by
e-mailing a request to the Blood
Publishing Office.
Other Resources
This section includes a list of Web links to patient groups and
other organizations that provide information.
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