TY - CHAP M1 - Book, Section TI - Thrombotic Microangiopathies A1 - Scully, Marie A2 - Kaushansky, Kenneth A2 - Prchal, Josef T. A2 - Burns, Linda J. A2 - Lichtman, Marshall A. A2 - Levi, Marcel A2 - Linch, David C. PY - 2021 T2 - Williams Hematology, 10e AB - SUMMARYThrombotic microangiopathy is a general term for the combination of microangiopathic hemolytic anemia and thrombocytopenia, often accompanied by signs and symptoms consistent with disseminated microvascular thrombosis. Thrombotic thrombocytopenic purpura (TTP) refers to thrombotic microangiopathy, without an obvious predisposing condition in the majority of cases. TTP is caused by autoantibodies to ADAMTS13 (a disintegrin and metalloprotease with a thrombospondin type 1 motif member 13), a plasma metalloprotease that normally cleaves von Willebrand factor (VWF) and regulates VWF-dependent platelet aggregation. Inherited deficiency of ADAMTS13 causes congenital TTP, which typically responds to plasma infusion. Most patients with acquired TTP respond to plasma exchange and immunosuppressive therapy, although many have relapsing disease. Hemolytic uremic syndrome (HUS) refers to thrombotic microangiopathy that usually causes oliguric or anuric acute kidney injury. Ingestion of Shiga toxin–producing Escherichia coli can cause the most common or “typical” form of HUS that is usually preceded by bloody diarrhea. Inherited or acquired defects in the regulation of the alternative complement pathway cause HUS to be referred to as “atypical” because it occurs without a prodrome of bloody diarrhea. Secondary thrombotic microangiopathy can occur in association with autoimmune disease, metastatic cancer, infections, organ transplantation, and certain drugs. These variants of thrombotic microangiopathy differ in pathogenesis and prognosis but can be difficult to distinguish because their clinical features often overlap. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1178755966 ER -