Thrombotic thrombocytopenic purpura and the atypical hemolytic uremic syndrome: an update.

Since the last review in 2007 of thrombotic thrombocytopenic purpura (TTP) and microangiopathic hemolytic anemia in the Clinics, further understanding of the nature of TTP and atypical hemolytic uremic syndrome (aHUS) has led to increasing use of rituximab in the treatment of TTP and the approval in 2011 of eculizumab for the treatment of aHUS. With this new armamentarium, distinction of aHUS from TTP has become more critical than ever. This article updates the new knowledge, highlights the difference between aHUS and TTP, and presents a scheme for their diagnosis and management.