Rare disorder of hemostasis in which there is a widespread intravascular formation of fibrin-platelet thrombi. It is sometimes associated with an acquired or inherited deficiency of the enzyme ADAMTS13, responsible for cleaving large multimers of von Willebrand factor.

- Often affects adult women- Inclusion criteria: Microangiopathic hemolytic anemia and thrombocytopenia, with or without renal failure or neurological abnormalities.- Widespread formation of platelet thrombi with fibrin (hyaline thrombi) leading to intravascular hemolysis (thrombotic microangiopathy)

Labs:- Decreased platelet count, prolonged bleeding time- Normal prothrombin time and partial thromboplastin time- Peripheral blood smear: thrombocytopenia, schistocytes, reticulocytosis

Treatment: plasma exchange