Neonatal atypical hemolytic uremic syndrome from a factor H mutation treated with eculizumab

Background: Atypical hemolytic uremic syndrome (aHUS) results from an inherited dysregulation of the alternative complement pathway leading to thrombotic microangiopathy consisting of hemolytic anemia, thrombocytopenia, and renal injury. The complement inhibitor eculizumab is an approved treatment, but its reported use in neonates – who have an inherently high risk of infection – is limited. Case diagnosis/treatment: A 28-day-old female presented with gross hematuria and hypertension. aHUS was suspected based on anemia with schistocytes, thrombocytopenia, low C3, and acute kidney injury requiring peritoneal dialysis. A septic work-up initiated on day 2 for hypothermia and respiratory failure was negative. There was no improvement after 6 days of plasma therapy. Despite being < 6 weeks old she was vaccinated with pneumococcal-13 conjugate, meningococcal (groups C and Y) polysaccharide, and Haemophilus b tetanus toxoid conjugate vaccines and started on penicillin prophylaxis. After 1 dose of eculizumab 300 mg, dialysis was discontinued and her hematological parameters improved. Genetic testing revealed a complement factor H mutation. After 11 months of follow-up, she remains on eculizumab and penicillin without recurrence of aHUS or any infectious complications. Conclusions: Eculizumab is a safe and effective treatment option for aHUS even in neonates at high risk for infection.