TTP is one of thrombotic microangipathies in which there is deficiency of ADAMTS13 (a vWF metalloprotease) which leads to increase in formation of large vWF multimers which increases platelets adhesion and aggregation (microthrombi formation). Clinically it present with fever, neurological symptoms, acute kidney injury and microangiopathic hemolytic anemia. Lab shows normal PT and PTT. Treatment is plasma exchange, glucocorticoid and rituximab