Catastrophic Antiphospholipid Syndrome: A Rare but Life‐Threatening Thrombotic Storm—A Case Report and Literature Review

Catastrophic antiphospholipid syndrome (CAPS) is a rare, life-threatening variant of antiphospholipid syndrome (APS) characterized by rapid, widespread thrombosis leading to multiorgan failure. Affecting less than 1% of APS patients, CAPS is associated with a high mortality rate of 30%-50%, necessitating prompt diagnosis and aggressive treatment. The mainstay of management includes anticoagulation, high-dose glucocorticoids, and plasma exchange or intravenous immunoglobulins, with biologic therapies such as rituximab and eculizumab reserved for refractory cases. We report a case of a 60-year-old male with a history of triple-antibody-positive APS complicated by recurrent diffuse alveolar hemorrhage (DAH), adrenal hemorrhage, chronic kidney disease, and superficial vein thrombosis. His condition progressed to CAPS approximately 5 years prior with a course complicated by heparin-induced thrombocytopenia. His condition stabilized with high-dose corticosteroids and rituximab therapy with sustained symptomatic improvement after 10 months of rituximab. This case highlights the complexity of CAPS diagnosis and management, in the context of DAH, emphasizing the importance of early recognition, multidisciplinary care, and individualized treatment strategies. Our patient's prolonged disease stabilization with rituximab underscores its potential role in long-term CAPS management. Further research is needed to refine treatment protocols and improve outcomes for this rare but life-threatening condition.