[Diagnosis and treatment of microangiopathic hemolytic anemia]

"Microangiopathic hemolytic anemia (MAHA)" is now used to designate any hemolytic anemia related to RBC fragmentation, occurring in association with small vessel disease. In DIC, RBC fragmentation is thought to result from the deposition of fibrin or platelets within the microvasculature. The term "thrombotic microangiopathy (TMA)" is also used to describe syndromes characterized by MAHA, thrombocytopenia, and thrombotic lesions in small blood vessels. The most prominent diagnoses associated with TMA are thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). Many different disorders, including preeclampsia, infections, adverse drug reactions, hematopoietic stem cell transplantation, autoimmune diseases, and malignancies, can cause TMA (i.e., secondary TMA). Recently, because the pathogeneses of TTP and HUS have been elucidated, great progress has been made in diagnosis and treatments. However, the pathogenesis of secondary TMA remains unclear. Clinical problems awaiting solution in TMA management include determination of the positioning of rituximab in the treatment sequence of primary TTP, management of Shiga-toxin producing Escherichia coli-HUS complicated by encephalopathy, confirmation of the efficacy and long-term safety of eculizumab in the treatment of atypical HUS, and elucidating the pathogenesis of secondary TMA as well as improving the efficacy of treatment.