Thrombotic thrombocytopenic purpura: 2008 update.

Thrombotic thrombocytopenic purpura (TTP) is a spectrum of syndromes characterized by thrombocytopenia and microangiopathic hemolytic anemia, manifested by an elevated blood lactate dehydrogenase (LDH) concentration and red blood cell fragments. It classically occurs in patients with a hereditary or acquired lack of ADAMTS13, a metalloproteinase that cleaves large multimers of von Willebrand factor. Other TTP-like syndromes, including TTP associated with pregnancy, organ transplantation, and certain medications, likely have different underlying causes and may require different treatment. Unless TTP is recognized promptly and treated aggressively, most patients die of it.