A Unique and Successful Story of Atypical Hemolytic Uremic Syndrome (aHUS)

Introduction: Microangiopathic hemolytic anemia, thrombocytopenia & end organ damage is a clinical scenario that can present in a plethora of similar conditions including TTP, HUS, aHUS & HELLP syndrome. The caveat being that establishing the correct diagnosis &starting treatment early is critical for good outcomes. Case Description: In this case, a 62-year-old female with a history of HTN & CKD3a with a recent COVID associated hospitalization a few months prior to presentation. The patient presented with progressive fatigue & headaches. She reported an associated unintentional 20 lb weight loss over 2 months& occasional foamy urine. Noted to be hypertensive with elevated Cr 5.4 (baseline of 1.7) & lab evidence of microangiopathic hemolytic anemia. The presence of schistocytes on peripheral smear was inconsistent. The majority of the workup was negative including Coombs, infectious & ADAMTS13 levels. Renal imaging was unremarkable. Patient underwent renal biopsy which revealed 15% globally sclerotic glomeruli w/ acute tubular injury without necrosis, interstitial fibrosis & edema involving 40-50% of cortical parenchyma, focal intimal thickening & hyalinosis. Immunofluorescence was unremarkable. Electron microscopy showed some ischemia with some podocyte foot process effacement. The patient was started alternating days of intermittent hemodialysis & plasmapheresis for 4 doses each without much improvement prior to being transferred for further treatment. Repeat testing showed continued mild hemolysis. After much review of the case & extensive discussions about the risks & possible benefits of using monoclonal C5 inhibitors & the possibility of renal recovery. Treatment of Eculizumab was started in the inpatient setting & discharged to continue treatment in the outpatient setting. On discharge, although the patient had some residual renal function, she was still dependent on hemodialysis. Genetic testing eventually returned with variant of Complement F associated with aHUS. Discussion: It is improtant to consider the totality of the case, not just limited to age while maintaing a broad differential & evaluate treatment response. In this case, based on the previous findings, presentation after transfer & renal biopsy results, the decision to treat for aHUS was made. Eventually, the patient was taken off dialysis & has continued treatment with Ravulizumab.