Diagnostic approach to microangiopathic hemolytic disorders

• Published in: International journal of laboratory hematology Vol. 39; no. S1; pp. 69 - 75
• Main Author: Kottke‐Marchant, K.
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01-05-2017
• Subjects: ADAMTS13; ADAMTS13 Protein - blood; Anemia; Anemia, Hemolytic - blood; Anemia, Hemolytic - diagnosis; atypical hemolytic uremic syndrome; Atypical Hemolytic Uremic Syndrome - blood; Atypical Hemolytic Uremic Syndrome - diagnosis; Complement system; Complement System Proteins - metabolism; complement‐mediated; Erythrocytes; Escherichia coli; Health risk assessment; Hemolysis; Hemolytic anemia; hemolytic uremic syndrome; Humans; Microvasculature; platelets; Proteolysis; Purpura; Purpura, Thrombotic Thrombocytopenic - blood; Purpura, Thrombotic Thrombocytopenic - diagnosis; Shiga toxin; Shiga Toxin - blood; Shiga-Toxigenic Escherichia coli - metabolism; Thrombocytopenic purpura; Thrombosis; Thrombosis - blood; Thrombosis - diagnosis; Thrombotic microangiopathy; Thrombotic thrombocytopenic purpura; Toxins; Von Willebrand factor; von Willebrand Factor - metabolism; atypical hemolytic uremic syndrome; Thrombotic microangiopathy; ADAMTS13; thrombosis; von Willebrand factor; thrombotic thrombocytopenic purpura; complement-mediated; hemolytic uremic syndrome; platelets
• ISSN: 1751-5521; 1751-553X
• DOI: 10.1111/ijlh.12671

Thrombotic micro‐angiopathies (TMA) are a group of related disorders that are characterized by thrombosis of the microvasculature and associated organ dysfunction, and encompass congenital, acquired, and infectious etiologies. A hall mark of TMAs is the fragmentation of erythrocytes by the microvascular thrombi, resulting in a hemolytic anemia. There are several distinct pathophysiologies leading to microangiopathic hemolysis, ranging from decreased degradation of von Willebrand factor as seen in thrombotic thrombocytopenic purpura (TTP) to endothelial damage facilitated by Escherichia coli shiga toxin or complement dysregulation, seen in shiga toxin‐related hemolytic‐uremic syndrome (Stx‐HUS) and complement‐mediated TMA (also called atypical hemolytic‐uremic syndrome), respectively. Distinguishing these disorders is important, as many TMAs are life‐threatening, the treatments are distinct and selecting appropriate therapy can improve patient prognosis. Laboratory testing, including measurement of ADAMTS13, ADAMTS13 inhibitor, shiga toxin, and complement factors, can help establish diagnoses and guide therapy.