Thrombotic Thrombocytopenic Purpura
(TTP; Moschcowitz Syndrome)
by Cynthia M. Johnson, MA
Thrombotic thrombocytopenic purpura (TTP) is a rare blood disorder. It makes blood clot in small blood vessels all over the body. This can block the flow of blood to major organs. It also uses up the platelets needed to help blood clot. This makes bleeding more likely and can lead to bruises.
There are two types:
TTP needs care right away.
A specific enzyme breaks down a protein that prevents excess clotting. Low levels of this enzyme, faulty enzymes, or delay with the enzyme, leads to excessive clotting.
People with acquired TTP have normal enzymes, but their activity is blocked or slowed by outside factors. It may be triggered by medical treatments or infections, especially those that affect the immune system. Normally, the immune system creates antibodies to fight foreign matter in the body like germs. However, sometimes these antibodies can affect healthy tissue. With TTP, the antibodies block the action of the enzymes.
Inherited TTP is caused by a defect of a specific gene. The defect prevents the body from creating the enzyme or creating effective enzymes.
TTP is more common in women, Black people, and young adults.
Health conditions that may be linked to TTP are:
Medical procedures or treatments that are linked to TTP are:
Problems may be:
The doctor will ask about your symptoms and health history. A physical exam will be done. You may need to see a doctor who treats blood disorders.
Blood tests will be done to look for signs of TTP, such as a low number of platelets and red blood cells.
More tests may be done to look for a cause.
A person may have TTP once or have repeated flare ups. Emergency care is needed to prevent damage to major organs and serious problems such as stroke. Choices are:
Cells in the spleen make the antibodies that block the enzyme activity. People with acquired TTP, those who do not get better with medicine, and those who have flare ups may need surgery to remove the spleen.
There are no known guidelines to prevent this health problem.
American Society of Hematology
National Heart, Lung, and Blood Institute
Canadian Blood Services
Public Health Agency of Canada
Scully M, Cataland S, et al; International Working Group for Thrombotic Thrombocytopenic Purpura. Consensus on the standardization of terminology in thrombotic thrombocytopenic purpura and related thrombotic microangiopathies. J Thromb Haemost. 2017 Feb;15(2):312-322.
Thrombotic thrombocytopenic purpura. National Heart, Lung, and Blood Institute website. Available at: https://www.nhlbi.nih.gov/health-topics/thrombotic-thrombocytopenic-purpura. Accessed February 12, 2021.
Thrombotic thrombocytopenic purpura (TTP). EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/thrombotic-thrombocytopenic-purpura-ttp. Accessed February 12, 2021.
Thrombotic thrombocytopenic purpura (TTP) and hemolytic-uremic syndrome (HUS). Merck Manual Professional Version website. Available at:
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Accessed February 12, 2021.
Last reviewed December 2020 by EBSCO Medical Review Board James P. Cornell, MD
Last Updated: 2/15/2021