Thrombotic thrombocytopenic purpura


Thrombotic thrombocytopenic purpura (TTP) is a blood disorder that causes blood clots to form in small blood vessels around the body, and leads to a low platelet count (thrombocytopenia).

See also: Hemolytic-uremic syndrome

Alternative Names



This disease may be caused by a lack of, or problems with, a certain enzyme (a type of protein) that is involved in blood clotting. These changes cause clotting to occur in an abnormal way.

In some cases, the disorder is passed down through families (inherited) and patients are born with naturally low levels of this enzyme. This condition also may be related to:


Exams and Tests


Plasma exchange (plasmapheresis plus infusion of donor plasma) is used to remove the antibodies that are affecting clotting from the blood and also replace the missing enzyme.

This treatment is repeated daily until blood tests show improvement.

People who do not respond to this treatment or whose condition often returns may need to:

Outlook (Prognosis)

Plasma exchange has greatly improved the outcome of this disease. Most patients now recover completely. However, some people die from this disease, especially if it is not found immediately. In people who don't recover, this condition can become long-term (chronic).

Possible Complications

When to Contact a Medical Professional

Call your health care provider if you have any unexplained bleeding.


Because the cause is unknown, there is no known way to prevent this condition.


McCrae KR, Sadler JE, Cines DB. Thrombotic thrombocytopenic purpura and the hemolytic uremic syndrome. In: Hoffman R, Benz EJ Jr, Shattil SJ, et al, eds. Hoffman Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Churchill Livingstone Elsevier;2008:chap 139.

Schafer A. Hemorrhagic disorders: Abnormalities of platelet and vascular function. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa:Saunders Elsevier;2007:chap 179.

Review Date: 2/28/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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