Genetic mutations in
complement components are associated with the development of
atypical hemolytic uremic syndrome (aHUS), a
rare disease with high morbidity rate triggered by
infections or unidentified factors. The uncontrolled activation of the alternative pathway of
complement results in systemic endothelial damage leading to progressive development of
renal failure. A previously healthy 8-month-old boy was referred to our hospital because of onset of
fever,
vomiting, and a single episode of nonbloody
diarrhea.
Acute kidney injury with preserved diuresis,
hemolytic anemia, and
thrombocytopenia were detected, and common protocols for management of HUS were followed without considerable improvement. The persistent low levels of
complement component C3 led us to hypothesize the occurrence of aHUS. In fact, the child carried a specific mutation in
complement factor H (Cfh;
nonsense mutation in 3514G>T, serum levels of Cfh 138 mg/L, normal range 350-750). Given the lack of response to
therapy and the occurrence of
kidney failure requiring dialysis, we used
eculizumab as rescue
therapy, a monoclonal humanized antibody against the
complement component C5. One week from the first administration, we observed a significant improvement of all clinical and laboratory parameters with complete recovery from
hemodialysis, even in the presence of systemic
infections. Our case report shows that
complement inhibiting treatment allows the preservation of renal function and avoids disease relapses during systemic
infections.