The Clinical Evaluation and Management of Thrombotic Microangiopathy.

Thrombotic microangiopathy (TMA) refers to a diverse group of diseases which share clinical and histopathologic features. TMA is clinically characterized by microangiopathic hemolytic anemia (MAHA), consumptive thrombocytopenia, and organ injury which stems from endothelial damage and vascular occlusion. There are several disease states with distinct pathophysiological mechanisms that manifest as TMA. These conditions are associated with significant morbidity and mortality and require urgent recognition and treatment. Thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS) are traditionally considered to be primary forms of TMA, but TMA more commonly occurs in association with a co-existing condition such as infection, pregnancy, autoimmune disease, or malignant hypertension, amongst others. Determining the cause of TMA is a diagnostic challenge due to limited availability of disease-specific testing. However, identifying the underlying etiology is imperative as treatment strategies differ. Our understanding of the conditions that cause TMA is evolving. Recent advances have led to improved comprehension of the varying pathogenic mechanisms that drive TMA. Development of targeted therapeutics has resulted in significant improvements in patient outcomes. In this article we review the pathogenesis and clinical features of the different TMA-causing conditions. We outline a practical approach to diagnosis and management and discuss empiric and disease-specific treatment strategies. This article is protected by copyright. All rights reserved.