Macrovascular involvement in a child with atypical hemolytic uremic syndrome

Background Atypical hemolytic uremic syndrome(aHUS) is a disorder of the complement systemwhich leads to thrombotic microangiopathy. It is caused by either acquired or hereditary defects in the activation or regulation of the alternative complement pathwayand is therefore considered to be a disease of local complementdysregulation in microvasculature with predominantly renal involvement. However, extrarenal manifestations are observed in approximately one-fifth of aHUS patients, with the myocardium and central nervous system (CNS) being involved most often. Additionally, there have been a few reports of aHUS with cerebral artery stenoses or periphereal gangrene, suggesting the possibility of ‘macrovascular’ involvement in aHUS.