SESSION TITLE: Pulmonary Manifestations of Systemic Disease Case Report Posters
SESSION TYPE: Affiliate Case Report Poster
PRESENTED ON: Tuesday, October 27, 2015 at 01:30 PM - 02:30 PM
INTRODUCTION: Atypical hemolytic uremic syndrome (aHUS) is a rare disease that represents a severe form of thrombotic microangiopathy (TMA). aHUS accounts for approximately 5-10% of all cases of hemolytic uremic syndrome (HUS).1 Development of aHUS results from either genetic or acquired disorders that lead to complement dysregulation.
CASE PRESENTATION: A 44 year-old female was admitted to the hospital with acute hypoxic respiratory failure and altered mental status. Past medical history was significant for left axillary carcinoma (ER, PR positive, HER-2 negative), hypertension, and recent admission for acute respiratory failure. Chest imaging revealed diffuse bilateral opacities consistent with severe pulmonary edema. Echocardiogram showed normal cardiac function. Laboratory workup revealed PaO2/FiO2 of 120, anemia, thrombocytopenia, elevated lactate dehydrogenase (2440 U/L), undetectable haptoglobin, and acute renal failure. Peripheral blood smear revealed schistocytes. ADAMTS-13 was mildly decreased at 43. C3 level was low and C4 level was normal. She was started on ARDSnet protocol for moderate acute respiratory distress syndrome (ARDS). With concern for thrombotic thrombocytopenic purpura versus HUS, plasmapheresis was initiated. Continuous renal replacement therapy was started due to worsening renal function. Renal biopsy revealed acute thrombotic microangiopathy (TMA) with cortical infarction. TMA profile revealed elevated Factor H and Factor H autoantibody. The patient’s respiratory status improved and she was extubated on hospital day 10. She was discharged with scheduled sessions of plasmapheresis and plans to start eculizumab for aHUS. She continues to require hemodialysis without signs of renal recovery.
DISCUSSION: Clinical outcomes are poor in patients with aHUS as mortality is approximately 25% in the acute phase. 50% of patients progress to end-stage renal disease requiring long-term dialysis.1 Early recognition and urgent workup is crucial in patients presenting with TMA as initiation of specific treatment (i.e. plasmapheresis and eculizumab) reduces risk of irreversible organ damage.
CONCLUSIONS: Diagnosis of aHUS is challenging secondary to variable clinical manifestations other than renal and neurological dysfunction and hypertension. To our knowledge, this is the first reported case of adult-onset Factor H autoantibody associated aHUS presenting as ARDS.
Reference #1: Yenerel M. Atypical Hemolytic Uremic Syndrome: Differential Diagnosis from TTP/HUS and Management. Turk J Haematol 2014 Sept; 31(3):216-225
DISCLOSURE: The following authors have nothing to disclose: Cynthia Tsai, Lindsay Smith, Meike Schuster, Susan Baro
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