A Simplified Approach to the Diagnosis of Atypical HUS: Clinical Considerations and Practical Implications

Abstract

Although rare, atypical hemolytic-uremic syndrome (aHUS) carries a high morbidity and mortality. Widespread microvascular thrombosis, thrombocytopenia and microangiopathic hemolytic anemia are the hallmark of aHUS. Virtually any organ (particularly the kidney) can be a target for the devastating effects of this syndrome. Uncontrolled activation of the alternative pathway of the complement system lies at the heart of the pathogenesis of aHUS. While significant advances have been made in our understanding of aHUS, establishing timely diagnosis of this syndrome has been challenging. This, in part, is due to the absence of a sensitive and specific diagnostic test and a relatively lack of our familiarity with the syndrome. With the recent success and approval of a humanized monoclonal antibody (eculizumab) in the treatment of aHUS, prompt and accurate diagnosis is of paramount importance to limit the target organ injury. This article presents a simplified approach to establishing the diagnosis of aHUS.