What Is Thrombotic Thrombocytopenic Purpura?
Thrombotic thrombocytopenic purpura (TTP) is a rare
blood condition. It causes blood clots to form in small blood vessels
throughout the body. These blood clots can cause serious problems if they block
blood vessels and limit blood flow to the brain, kidneys, or heart.
Blood clots form when blood cells called platelets
(PLATE-lets) clump together. Platelets are made in your bone marrow along with
other kinds of blood cells. They stick together to seal small cuts or breaks
and stop bleeding.
In TTP, when blood clots form, there are fewer
platelets in the blood. This can cause bleeding into the skin (purpura),
prolonged bleeding from cuts, and internal bleeding. It also causes small blood
clots to form suddenly throughout the body, including in the brain and
kidneys.
Thrombotic (throm-BOT-ik) refers to the blood clots
that form. Thrombocytopenic (throm-bo-cy-toe-PEE-nick) means theres a
lower than normal number of platelets in the blood. Purpura (PURR-purr-ah) are
purple bruises caused by bleeding into the skin.
Purpura
![Photograph showing purpura (bleeding) in the skin](https://webarchive.library.unt.edu/web/20090506120534im_/http://www.nhlbi.nih.gov/health/dci/images/itp_photo.jpg)
The photograph show purpura
(bleeding) in the skin. Bleeding under the skin causes the purple, brown, and
red color of the purpura.
TTP also can cause red blood cells to break apart
faster than the body can replace them. This leads to
hemolytic
anemia (HEE-moh-lit-ick uh-NEE-me-uh)a rare form of
anemia.
Anemia is a condition in which a persons blood doesnt have enough
red blood cells.
A lack of activity in the ADAMTS13 enzyme (a type of
protein in the blood) causes TTP. The ADAMTS13 gene controls the enzyme, which
is involved in blood clotting. The enzyme breaks up a large protein called von
Willebrand factor that clumps together with platelets to form blood clots.
Types of Thrombotic Thrombocytopenic Purpura
TTP has two main types: inherited and acquired
(noninherited) TTP.
Inherited means the condition is passed
from parents to children. This type of TTP mainly affects newborns and
children. In inherited TTP, the ADAMTS13 gene is faulty and doesnt prompt
the body to make a normal ADAMTS13 enzyme. As a result, enzyme activity is
lacking or is changed.
Acquired TTP is the more common type.
Acquired means you arent born with the condition, but you
develop it. This type of TTP occurs mostly in adults, but it sometimes affects
children.
In acquired TTP, the ADAMTS13 gene isnt
changed. Instead, the body makes proteins called antibodies that block the
ADAMTS13 enzymes activity.
What triggers inherited and acquired TTP isnt
known, but some factors may play a role. These include:
- Diseases and conditions such as pregnancy,
cancer, HIV, infection, and lupus
- Medical procedures such as surgery and bone
marrow transplant
- Medicines such as chemotherapy, ticlopidine,
clopidogrel, cyclosporine A, and hormone replacement therapy and estrogens
Outlook
TTP is a rare condition. It can be fatal or cause
lasting damage, such as brain damage or stroke, if its not treated right
away. About 1,200 people develop acquired TTP each year in the United States.
TTP usually occurs suddenly and lasts for days and
weeks, but it can continue for months. Most people recover fully from TTP when
treated promptly. Relapses (or flareups) can occur in 30 to 60 percent of
people with acquired TTP. Many people with inherited TTP have frequent flareups
that need to be treated.
Treatments for TTP include infusions of fresh frozen
plasma and plasma exchange (also called plasmapheresis (PLAZ-ma-fe-RE-sis)).
These treatments have greatly improved the outlook of the disease.
September 2007 |