Atypical hemolytic uremic syndrome is a
thrombotic microangiopathy characterized by
hemolysis,
thrombocytopenia, and
acute kidney injury, usually caused by alternative
complement system overactivation due to pathogenic genetic variants or
antibodies to components or regulatory factors in this pathway. Previously, a lack of effective treatment for this condition was associated with mortality,
end-stage kidney disease, and the risk of disease recurrence after
kidney transplantation. Plasma
therapy has been used for
atypical hemolytic uremic syndrome treatment with inconsistent results.
Complement-blocking treatment changed the outcome and prognosis of patients with
atypical hemolytic uremic syndrome. Early administration of
eculizumab, a monoclonal C5 antibody, leads to improvements in hematologic, kidney, and systemic manifestations in patients with
atypical hemolytic uremic syndrome, even with apparent dialysis dependency. Pre- and post-transplant use of
eculizumab is effective in the prevention of
atypical hemolytic uremic syndrome recurrence. Evidence on
eculizumab use in secondary
hemolytic uremic syndrome cases is controversial. Recent data favor the restrictive use of
eculizumab in carefully selected
atypical hemolytic uremic syndrome cases, but close monitoring for relapse after
drug discontinuation is emphasized. Prophylaxis for
meningococcal infection is important. The long-acting C5
monoclonal antibody ravulizumab is now approved for
atypical hemolytic uremic syndrome treatment, enabling a reduction in the dosing frequency and improving the quality of life in patients with
atypical hemolytic uremic syndrome. New strategies for additional and novel
complement blockage medications in
atypical hemolytic uremic syndrome are under investigation.