Hemolytic uremic syndrome (HUS) is a clinical syndrome characterized by the 
triad of thrombotic microangiopathy, thrombocytopenia, and acute kidney injury. 
Hemolytic uremic syndrome represents a heterogeneous group of disorders with 
variable etiologies that result in differences in presentation, management and 
outcome. In recent years, better understanding of the HUS, especially those due 
to genetic mutations in the alternative complement pathway have provided an 
update on the terminology, classification, and treatment of the disease. This 
review will provide the updated classification of the disease and the current 
diagnostic and therapeutic approaches on the complement-mediated HUS in addition 
to STEC-HUS which is the most common cause of the HUS in childhood.