Subclinical activity of atypical hemolytic uremic syndrome and eculizumab treatment (Clinical observation)

Abstract

Atypical hemolytic uremic syndrome (aHUS) is a rare, life-threatening disease related to uncontrolled complement activation. Until recently, the management of aHUS consisted of early and intensive plasma exchange, although this was mostly ineffective in protecting from subsequent organ damage. Eculizumab, an inhibitor of the alternative complement pathway, produces a rapid and sustained inhibition of the thrombotic microangiopathy process, with significant improvements in long-term clinical outcomes. Due to the significant improvement achieved, eculizumab has subsequently been approved as the first-line therapy when an unequivocal diagnosis of aHUS has been made. The use of eculizumab has changed the management and the outcome of aHUS, becoming the frontline treatment of the disease. We report a case of a 13 year-old boy with aHUS who got eculizumab because of persistent non-specific clinical symptoms in the absence of laboratory evidence of active thrombotic microangiopathy. The use of eculizumab was associated with a significant decrease in proteinuria, anemia, increased GFR and an improvement in general state, revealing that the subclinical symptoms were caused by unsuspected disease activity.