BACKGROUND: Thrombotic thrombocytopenic purpura (TTP), in 1924 first described 
by Moschcowitz, is a clinically heterogeneous syndrome associated with 
thrombocytopenia, Coombs-negative hemolytic anemia, neurologic changes, renal 
impairment, and fever. TTP is found after various bacterial or viral infectious 
diseases, autoimmune diseases and also in association with different drugs.
PATHOGENESIS: After initial endothelial cell injury unusually large von 
Willebrand factors (vWF) are found in plasma of patients with thrombotic 
thrombocytopenic purpura. Because of impaired proteolysis these large forms lead 
to thrombosis of the small vessels. The microangiopathy is followed by 
mechanical destruction of red cells. In peripheral blood smears these 
fragmentocytes are important for diagnosis and clinical course.
THERAPY: The therapy of choice is plasma exchange against fresh frozen plasma, 
whereupon the mortality could be dramatically reduced in the past decades. In 
case of treatment resistance to plasma exchange there exists no common treatment 
schedule. One therapy option is immunosuppressive treatment with corticosteroids 
and vincristine. In case of chronic relapsing TTP splenectomy should be 
discussed. In spite of severe thrombocytopenia substitution of thrombocytes is 
contraindicated.