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Abstract: TH-PO817

How Factor H Deficiency Triggered Atypical Hemolytic Uremic Syndrome (aHUS) in a New Mother

Session Information

Category: Pathology and Lab Medicine

  • 1800 Pathology and Lab Medicine


  • Ho, Thien, Medical University of South Carolina, Charleston, South Carolina, United States
  • Mai, Erik, Medical University of South Carolina, Charleston, South Carolina, United States
  • Bruner, Evelyn, Medical University of South Carolina, Charleston, South Carolina, United States
  • Budisavljevic, Milos N., Medical University of South Carolina, Charleston, South Carolina, United States

Atypical Hemolytic Uremic Syndrome (aHUS) is a rare form of thrombotic microangiopathy (TMA) causing dysregulation of the alternative complement system. aHUS presents with microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and organ damage, notably, renal failure requiring dialysis. Morbidity and mortality is preventable as treatments are now available. Yet, treatment is often delayed as aHUS is viewed as an exclusion diagnosis. Prior studies have shown that aHUS is associated with many genetic mutations of complement proteins. Of these, Factor H (CFH) were found in 25% of cases. We present an aHUS case of CFH deficiency in a postpartum patient.

Case Description

A 26 year old healthy female, who one week ago had a normal term vaginal delivery, presented with hypertensive emergency, MAHA, thrombocytopenia, and renal failure requiring dialysis. Initial labs showed deficient C3 levels and normal C4 levels. Plasmapheresis was started for suspicion of Thrombotic Thrombocytopenic Purpura. Therapy was stopped when her ADAMTS13 returned normal. She was screened for infections, drugs, and malignancy, all were negative.

A renal biopsy showed TMA with 10% cortical necrosis. Results of her complement panel showed dysregulation of the alternative pathway: low CFH and low alternative pathway levels. She was diagnosed with aHUS and treated with a C5 Inhibitor, Eculizumab. Eculizumab was given weekly and after her third dose, her hemolytic labs improved. After her 4th dose, her renal function was near complete recovery and dialysis stopped. Her dose now was every two weeks for a minimum of six months.


C5 inhibitors have hugely improved renal survival. Our patient received Eculizumab with promising renal recovery. A 2010 study of 100 females with aHUS showed that 48% of cases involved CFH mutations. Another study assessed 273 aHUS patients and 139 had CFH dysfunction. We are learning that the defect affects more than one area on the CFH gene. Thus, the location of dysfunction affects the severity and treatment response making aHUS much more challenging to standardize.