Refractory Atypical Hemolytic Uremic Syndrome

Abstract 4635

Atypical hemolytic uremic syndrome is a rare but often lethal disease if not diagnosed and treated early. The mainstay of treatment has been plasma exchange, though eculizumab has recently been approved for treatment.

We report a 24-year-old Caucasian male whom presented from a rehab facility with weakness. Three months prior, he had sustained polytrauma from a motorcycle accident. At discharge, labs were normal. At admission, he was found to have anemia, thrombocytopenia, and elevated creatinine and bilirubin. Further testing revealed evidence of hemolysis. ADAMTS13 level was greater than 100% to assess for thrombotic thrombocytopenic purpura (TTP). Flow cytometry for CD59 was negative to assess for paroxysmal nocturnal hemoglobinuria (PNH). Shiga toxin was negative. He was diagnosed with atypical hemolytic uremia syndrome (aHUS). Patient was initially treated with steroids then underwent daily plasma exchange for 2 weeks with improvements in lab parameters and no evidence of hemolysis. Exchanges were changed to every other day for 2 weeks with plans to start eculizumab as outpatient therapy. After discharge, one dose of eculizumab 900 mg was given without further exchanges. Three days later, lab check showed decrease in hemoglobin and platelets, concerning for aHUS exacerbation. Patient was admitted for daily plasma exchange with eculizumab 100 mg boost after each procedure for about 2 weeks. Once his lab parameters were consistent with resolution, exchanges were spaced out to every other day for another 1 week then discontinued. Then he was started on monotherapy with eculizumab 900 mg once weekly with surveillance lab monitoring. He had no further exacerbation of his aHUS and was discharged back to rehab with weekly eculizumab and lab surveillance.

Early detection and treatment of aHUS is important to minimize the damages from the underlying thrombosis and prevent disease related mortality. Plasma exchange remains the standard treatment for this condition with close monitoring of lab parameters, though no set treatment schedule has been established. The recent approval of eculizumab offers another option in the management of this disease and appears equally efficacious.