Aorto to alveoli: catastrophic antiphospholipid syndrome masquerading as multisystem failure

Abstract

Catastrophic Antiphospholipid Syndrome (CAPS) is a rare, fulminant variant of antiphospholipid syndrome, characterized by rapid multi-organ involvement due to widespread thrombosis. We report a 65-year-old male, with prior comorbidities such as diabetes, hypertension, dyslipidemia, cerebrovascular accident and coronary artery disease who presented with complete thrombosis of the distal abdominal aorta and common iliac vessels. During hospital stay, he developed acute respiratory distress, right-sided haemothorax with massive pleural effusion, diffuse alveolar haemorrhage, acute kidney injury with microscopic haematuria, and neurological deterioration requiring mechanical ventilation. Initial autoimmune workup was negative for ANA, ANCA, and anti-GBM antibodies. However, β2-glycoprotein IgG was strongly positive, and anticardiolipin antibody was borderline positive, raising suspicion of CAPS. Given the constellation of multiorgan dysfunction with diffuse alveolar haemorrhage and vascular thrombosis, a diagnosis of catastrophic APS was considered. The patient underwent aggressive multimodal therapy including pulse corticosteroids, anticoagulation, renal replacement therapy, immunomodulators, and ventilatory support. Plasma exchange/IVIG was planned in case of further worsening. With multidisciplinary management and intensive supportive care, the patient showed gradual recovery, and was discharged in a stable condition. This case highlights the diagnostic challenge of CAPS, which often masquerades as vasculitis, sepsis, or other autoimmune diseases. It also underlines the management hurdles, requiring timely recognition, multidisciplinary coordination, and combined immunosuppression and anticoagulation. Despite its rarity, CAPS should be considered in patients with rapidly progressive multiorgan thrombosis, as early diagnosis and intervention can be life-saving.