Case series: coronavirus disease 2019 infection as a precipitant of atypical hemolytic uremic syndrome: two case reports

BACKGROUND: Atypical hemolytic uremic syndrome is an exceedingly rare thrombotic microangiopathy caused by accelerated activation of the alternative complement pathway. CASE PRESENTATION: Here, we report two cases of patients presenting with suspected atypical hemolytic uremic syndrome precipitated by coronavirus disease 2019 infection. The first patient, a 25-year-old Hispanic male, had one prior episode of thrombotic microangiopathy presumed to be atypical hemolytic uremic syndrome precipitated by influenza A, and re-presented with thrombocytopenia, microangiopathic hemolytic anemia, nonoliguric renal failure, and normal ADAMTS13 activity, with confirmed coronavirus disease 2019 positivity. The second patient, a 31-year-old Caucasian female, had no personal history of thrombotic microangiopathy, though reported a family history of suspected atypical hemolytic uremic syndrome. She presented with similar laboratory derangements, oliguric renal failure requiring hemodialysis, and confirmed coronavirus disease 2019 positivity. Both patients were treated with eculizumab with complete resolution of their hematologic and renal complications. CONCLUSION: To our knowledge, this represents the largest case series of atypical hemolytic uremic syndrome precipitated by coronavirus disease 2019 in adults.