(461) Catastrophic Antiphospholipid Syndrome: Severe Presentation and Management of a Rare Disease

Introduction: Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the formation of procoagulant antiphospholipid antibodies resulting in recurrent thrombotic events that can affect any organ system. The most severe form, catastrophic APS (CAPS), presents acutely with multifocal vascular thromboses resulting in multisystem organ failure and can be fatal even when treated aggressively.

Description: A 33-year-old male with a history of immune thrombocytopenia status-post splenectomy presented with left lower extremity pain and was found to have a femoral artery occlusion. He was started on a heparin infusion and underwent thrombectomy and catheter-directed thrombolysis of the left femoral artery. Percutaneous revascularization was unsuccessful, culminating in an above-the-knee amputation on hospital day 3. Over this time, he also developed multiorgan failure, requiring post-operative mechanical ventilation for acute hypoxemic respiratory failure, norepinephrine for hypotension, and the initiation of continuous renal replacement therapy for oliguric acute kidney injury. He was noted to be paraplegic, and neuroimaging showed multifocal cerebral and thoracic spinal cord infarcts of thrombotic etiology. Hematological work-up ruled out many potential causes of arterial thrombi, and a diagnosis of CAPS was made. He was started on high-dose steroids and IVIG followed by plasmapheresis. He developed hemorrhagic shock requiring blood transfusions due to melena. On hospital day 11, he was transferred to a nearby academic medical center. Endoscopy and imaging on hospital day 14 showed ischemic colitis and renal infarctions, prompting a total colectomy. Rapid intraoperative clot formation was noted by the surgical team despite therapeutic bivalirudin, so second-line CAPS therapy with eculizumab was initiated. After multiple abdominal operations, the patient defervesced and was weaned from pressors, mechanical ventilatory support, and renal replacement therapy, and he was ultimately discharged home.

Discussion: This case illustrates the fulminant clinical course of CAPS. A high index of suspicion for CAPS in patients with multifocal arterial thromboses is imperative, and second-line therapies should be considered in patients with clot burden progression despite therapeutic anticoagulation.