SESSION TITLE: Pulmonary Vascular Disease SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: The ANCA-associated vasculitides are a group of rare disorders that affect multiple organ systems and can present in a variety of ways, including as diffuse alveolar hemorrhage (DAH). Interestingly, there have also been reports of ANCA-associated vasculitis complicated by thrombotic thrombocytopenic purpura (TTP), although this is only described in case series. Common treatments for vasculitis flares include high-dose steroids plus either rituximab or cyclophosphamide. In severe refractory cases, there may be a role for plasma exchange (PLEX), although confirmation of these results from large trials is still pending. The following patient case illustrates a rare presentation of an ANCA-associated vasculitis flare complicated by DAH and TTP that resolved with PLEX. CASE PRESENTATION: An 82-year-old woman with microscopic polyangiitis presented to our hospital with hemoptysis. On admission, she required 4 liters of oxygen to maintain her saturation above 90%. Labs revealed a hemoglobin of 5.0g/dL and elevated myeloperoxidase (MPO) antibody with positive p-ANCA antibody. A CT of her chest was performed and showed diffuse, bilateral, alveolar infiltrates suggestive of DAH. She was admitted to the intensive care unit (ICU) and started on high dose methylprednisolone plus rituximab while also receiving red blood cells. Over the next two days of her stay, there was significant clinical improvement. However, on hospital day three, she again experienced hemoptysis with increasing oxygen requirements. At the same time, her hemoglobin and platelets both dropped significantly. Hemolysis was suggested by an elevated LDH and bilirubin with decreased haptoglobin. These findings led to further evaluation, which ultimately revealed a decreased ADAMTS13 value consistent with concurrent TTP. Given her worsening clinical status, failure of standard therapies, and development of TTP, the decision was made to start plasma exchange. After two sessions of PLEX, her overall clinical status rapidly improved with rising blood counts coupled with decreasing symptomatology and oxygen requirements. She ultimately finished seven PLEX sessions with complete resolution of her symptoms and has done well on subsequent follow-up. DISCUSSION: This case demonstrates the rare association between ANCA-associated vasculitis and TTP as well as the potential for plasma exchange to treat the co-occurrence of both diseases effectively. In the literature, there have been fewer than 20 case reports of an ANCA-associated vasculitis complicated by DAH and TTP, all of which were successfully treated with PLEX. CONCLUSIONS: In this case, the co-occurrence of TTP and relapse of ANCA-associated vasculitis in a critically ill patient drove the initiation of plasma exchange and ultimately led to rapid clinical improvement. Reference #1: 1. Jordan JM, Manning M, Bates Allen N. Multiple unusual manifestation of Wegener's granulomatosis: breast mass, microangiopathic hemolytic anemia, comsumptive coagulopathy and low erythrocyte sedimentation rate. Arthritis Rheum. 1986;29:1527-31 Reference #2: 2. von Baeyer H. Plasmapheresis in thrombotic microangiopathy-associated syndromes: review of outcome data derived from clinical trials and open studies. Ther Apher. 2002;6:320-328. Reference #3: 4. Yamauchi Y, Nagatoya K, Okuno A, Fujii N, Inoue T. Successful treatment for thrombotic thrombocytopenic purpura complicated with myeloperoxidase anti-neutrophil cytoplasmic autoantibody-associated vasculitis. NDT Plus. 2010;3(3):279-281. https://doi.org/10.1093/ndtplus/sfq013. DISCLOSURES: No relevant relationships by Timothy Dempsey, source=Web Response No relevant relationships by Patricio Escalante, source=Web Response No relevant relationships by Tobias Peikert, source=Web Response