(435) Probable CAPS in a 33-Year-Old Male With New-Onset Arterial Thrombosis: A Case Report

Introduction: Antiphospholipid Syndrome (APS) is an autoimmune condition characterized by thrombotic events due to antiphospholipid antibodies. Approximately 1% of APS patients develop a more severe form termed catastrophic APS (CAPS) with multiple thromboses developed in a short time interval resulting in damage to several organ systems.

Description: A 33-year-old male with a history of Immune Thrombocytopenic Purpura status-post splenectomy as a child presented with acute limb ischemia. A heparin infusion was started and he underwent thrombolysis catheter placement. He later developed undifferentiated shock and returned to the OR for amputation. Post-operatively, he developed acute kidney injury requiring initiation of CRRT. CT showed bilateral renal infarcts. He also developed altered mental status and RLE paralysis with MRI showing scattered cerebral infarcts as well as thoracic spine infarcts. He was continued on heparin and started on therapies for suspected CAPS including high-dose steroids, IVIG and plasmapheresis. Laboratory workup was significant for thrombocytopenia of 86,000/µL, ferritin of 25,000 ng/mL, positive anti-cardiolipin IgG 26 GPL U/mL, negative anti-β2 glycoprotein, negative serotonin release assay to exclude HIT, ADAMTS13 of 38% to exclude TTP, normal fibrinogen of 549 mg/dL to exclude DIC. Despite adequate first-line therapy, he developed GI bleed with colonoscopy findings consistent with ischemic colitis. He required total abdominal colectomy with end ileostomy. He was transitioned to bivalirudin for anticoagulation and initiated on second-line therapy with eculizumab. He was given meningococcal and pneumococcal vaccinations and started on penicillin for meningitis prophylaxis. He had no additional thrombotic events and was bridged to warfarin. He was transferred out of ICU care after 34 days.

Discussion: CAPS is a rare life-threatening disease. Our patient had three of four diagnostic criteria including involvement of 3+ organ systems, manifestation within less than a week, and the presence of anti-cardiolipin antibodies, fitting the diagnosis of probable CAPS. Roughly 7% of patient on the CAPS Registry have been treated with eculizumab. Our case describes an uncommon circumstance requiring second-line therapy for the treatment of CAPS.