Kidney Week

Abstract: PUB500

Role of Eculizumab in Dialysis Dependent AKI Secondary to Atypical Hemolytic Uremic Syndrome

Session Information

• Publication Only

Category: Trainee Case Reports

• 103 AKI: Mechanisms

Authors

• Robinson, Katherine R., University of South Florida, Lutz, Florida, United States

Katherine R. Robinson,

• Shirley, Kayla, University of South Florida, Lutz, Florida, United States

Kayla Shirley,

• Abu Al Rub, Fadee, University of South Florida, Lutz, Florida, United States

Fadee Abu Al Rub,

• Bassil, Claude, University of South Florida, Lutz, Florida, United States

Claude Bassil,

• Fu, Liying, Tampa General Hospital, Tampa, Florida, United States

Liying Fu,

Introduction

Thrombotic microangiopathies represent 3 syndromes: hemolytic uremic syndrome (HUS), thrombotic thrombocytopenic purpura, and atypical HUS (aHUS). While microvessel wall thickening and intraluminal thrombosis characterizes the pathology, the pathogenesis and prognosis for each disorder is variable. HUS is defined by a triad of microangiopathic hemolytic anemia (MAHA), thrombocytopenia and AKI. aHUS is then divided into two groups, typical (diarrheal) and atypical (non-diarrheal) HUS.

Case Description

A 65-year-old female with HTN, MDS and MGUS, presented to the ED with fatigue. Refer to Table 1 for lab findings. For the past 6 months, serial peripheral smears demonstrated increasing number of schistocytes. Renal ultrasound ruled out obstruction. Urine studies showed microscopic hematuria and 24h urine protein of 1.1g. As testing ruled out disseminated intravascular coagulation and suggested MAHA, therapeutic plasma exchange was given empirically until ADAMTS13 activity returned normal. Hemodialysis (HD) was then started for volume overload. Renal biopsy showed acute and severe chronic thrombotic microangiopathy-type injury, acute tubular necrosis and focal tubulointerstitial nephritis. Given lack of prodromal diarrhea, aHUS was diagnosed and she received corticosteroids followed by eculizumab. Her renal function and platelet counts recovered requiring 6 weeks of HD although she will require lifelong eculizumab therapy. Genetic testing for abnormal complement factors is pending.

Discussion

aHUS is an uncommon type of microangiopathy with incidence of 1 per million. Dysregulation of complement activation in the alternate pathway secondary to abnormal complement factors, with subsequent endothelial injury, typifies the pathogenesis of aHUS. As more genetic mutations are recognized it is becoming an increasingly understood clinical entity. Previously, standard first-line therapy consisted of plasma exchange followed by immunosuppression. The monoclonal antibody eculizumab has gained popularity in aHUS treatment by binding complement C5. Although eculizumab has been used more often for aHUS our case reflects the efficacy of this agent in a dialysis dependent patient if started immediately after the diagnosis has been made.