Atypical Hemolytic Uremic Syndrome: When the Environment and Mutations Affect Organ Systems. A Case Report with Review of Literature

Atypical hemolytic uremic syndrome (aHUS) is a rare thrombotic microangiopathy (TMA) with a genetic predisposition. Like other TMAs, it presents clinically with thrombocytopenia and microangiopathic hemolytic anemia, which is accompanied by disruption of at least one organ system. In general, it is important to distinguish aHUS from other TMAs because of the different prognosis and treatment options. We present a case of a 42-year-old female who presented with abdominal pain, nausea and vomiting. She had hemolytic anemia, thrombocytopenia and acute kidney injury suggestive of TMA. She was started on hemodialysis and plasma exchange and had an extensive workup including ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), which was normal, and complement factor mutations, which showed a complement factor H-related protein mutation. The diagnosis of aHUS was confirmed; plasma exchange was stopped; and she was started on eculizumab, which she tolerated well. However, she was diagnosed with end-stage renal disease and will need longterm renal replacement therapy.