Eculizumab therapy in a child with hemolytic uremic syndrome and CFI mutation.

Background: Hemolytic uremic syndrome (HUS) is the most common cause of acute renal failure in childhood. It usually occurs after a prodromal episode of diarrhea and it leads to significant morbidity and mortality during the acute phase. However, cases that start as diarrhea-positive HUS whose renal function fail to recover should be screened for genetic disorders of the complement system, which is called atypical HUS (aHUS).

Case-diagnosis/treatment: We herein report a 10-year-old girl, who initially came with bloody diarrhea and had features of HUS with delayed renal and hematological recovery despite plasma therapy. Eculizumab (600 mg/week) was initiated on day 15 for atypical presentation and later a complement factor I (CFI) mutation was detected. The girl recovered diuresis within 24 h and after the third eculizumab infusion, hemoglobin, platelet, and C3 levels normalized; renal function improved; and proteinuria completely disappeared in 2 weeks.

Conclusion: It is our belief that eculizumab can be the treatment of choice in children who have plasma exchange-refractory HUS with defective regulation of the alternative complement pathway.