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Kidney Week

Abstract: PO1855

Development of Atypical Hemolytic Uremic Syndrome in a Patient with Complement 3 Glomerulonephritis

Session Information

Category: Trainee Case Report

  • 1203 Glomerular Diseases: Clinical, Outcomes, and Trials


  • Patel, Ravi V., University of Wisconsin-Madison, Madison, Wisconsin, United States
  • Bhutani, Gauri, University of Wisconsin-Madison, Madison, Wisconsin, United States
  • Singh, Tripti, University of Wisconsin-Madison, Madison, Wisconsin, United States

Uncontrolled hyperactivity of alternative complement pathway has been implicated in development of two distinct pathological processes, namely C3 glomerulonephritis (C3GN) and atypical hemolytic uremic syndrome (aHUS). Here we present a unique case which initially started as C3GN on kidney biopsy and progressed to aHUS.

Case Description

68-year-old female presented with progressive weakness and palpitations over a month. She denied any fever, chills, dysuria, chest pain, dyspnea or abdominal pain. Her past medical history was significant for hypertension and coronary artery disease, with no family history of end stage renal disease. On admission, her medications included amlodipine for hypertension, levothyroxine for hypothyroidism and intermittent steroids for gouty arthritis. On exam, her vital signs revealed tachycardia with heart rate 119 beats/min and hypotension with blood pressure 97/59 mmHg. Exam was significant for dry mucosa and irregular heart rate. Initial laboratory evaluation was significant for acute kidney injury (AKI), with creatinine (Cr) of 2.6 (baseline Cr of 1.2). Urinalysis demonstrated 21-50 RBC/hpf and urine protein/Cr of 12.5 g/g. A renal biopsy was performed which showed endocapillary proliferation with dominant staining for C3 in the mesangium and along the capillary wall, consistent with C3GN. The patient was started on prednisone 60 mg daily. Hemodialysis was initiated for uremic symptoms. Complement function test was consistent with ongoing complement dysregulation at C3 convertase level and C5 convertase level without the presence of autoantibodies towards complement proteins. 2 months after her kidney biopsy, she developed worsening anemia and thrombocytopenia, elevated lactate dehydrogenase and undetectable haptoglobin. Direct coombs test was negative, peripheral smear showed schistocytes, ADAMTS13 level was 65%, consistent with diagnosis of atypical hemolytic uremic syndrome. Patient was started on Eculizumab therapy with stabilization of hemoglobin and platelets but remains dialysis dependant.


In our growing understanding of alternative complement pathway, it is thought that dysregulation at fluid state is associated with C3GN, while solid state dysregulation is associated with widespread endothelial injury leading to aHUS. Our patient developed both pathologies, suggests further research is needed in understanding the details of complement system.