Hemolytic uremic syndrome

Abstract

Hemolytic uremic syndrome (HUS) is thrombotic microangiopathy characterized by thrombocytopenia, non-immune microangiopathic hemolytic anemia and acute kidney injury. HUS is usually categorized as typical, caused by Shiga toxin-producing Escherichia Coli (STEC) infection, often associated with diarrhea (D+HUS), as atypical HUS due to dysregulated complement activation, not diarrhea associated (D-HUS, aHUS) or more rarely as secondary forms caused by systemic diseases or physiopathological conditions such as infections, malignancy, pregnancy, autoimmune disease, after transplantation or after drug assumption. The common pathogenetic features in STEC-HUS, aHUS, and secondary HUS are simultaneous damage of endothelial cells, intravascular hemolysis, and activation of platelets leading to a procoagulative state, formation of microthrombi, and tissue damage. HUS can develop in response to several different triggers and various clinical situations. The symptoms and clinical signs may overlap among the different forms of HUS; therefore, early diagnosis and identification of underlying pathogenic mechanisms allow instating specific support measures and therapies.