Thrombotic thrombocytopenic purpura

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Blood cells

TTP is a blood disorder characterized by low platelets, low red blood cell count (caused by premature breakdown of the cells), abnormalities in kidney function, and neurological (nervous system) abnormalities. A similar condition is hemolytic-uremic syndrome.

TTP

In some cases, this disease is caused by a deficiency in an enzyme (a type of protein) called the von Willebrand Factor cleaving protease (also called ADAMTS13). Loss of this enzyme results in large complexes of von Willebrand factor circulating in the blood, which in turn causes platelet clumping and red blood cell destruction.

Although most cases have no known cause, some cases may be related to a deficiency of ADAMTS13 at birth, cancer, chemotherapy, HIV infection, hormone replacement therapy and estrogens, and a number of medications in common use (including ticlopidine, clopidogrel, and cyclosporine A).

Review Date: 07/29/2005
Reviewed By: William Matsui, M.D., Assistant Professor of Oncology, Division of Hematologic Malignancies, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Baltimore, MD. Review provided by VeriMed Healthcare Network.