[A hemolytic episode following COVID-19 in a case with atypical hemolytic uremic syndrome].

Atypical hemolytic uremic syndrome (aHUS) is a lethal disease resulting in systemic thrombotic microangiopathies due to complement dysregulation. Immune activation by viral infections, such as SARS-CoV-2, may trigger hemolytic attack. A 38-year-old man, who had been previously diagnosed with aHUS due to complement component 3 mutation, was proven to be positive for SARS-CoV-2 without respiratory symptoms. No specific intervention was given to the patient, and he developed hematuria and oliguria three days after diagnosis. The patient was subsequently referred to our hospital and treated with eculizumab (900 mg). Afterward, the hemolytic symptoms improved rapidly. To the best of our knowledge, there have been reports of at least ten cases of hemolysis triggered by COVID-19 in patients with aHUS, and a potential clinical benefit of eculizumab for hemolytic attack, as well as for COVID-19, has been suggested. Here, we report the findings of a case, which indicate the efficacy of eculizumab introduction at an early stage.