Systemic Embolism Following Mechanical Thrombectomy for Acute Ischemic Stroke: A Case of Suspected Catastrophic Antiphospholipid Syndrome.

Objective: Catastrophic antiphospholipid syndrome (CAPS) is a disease characterized by a poor prognosis and a high mortality rate, leading to systemic thrombosis. Approximately two-thirds of CAPS cases are associated with conditions such as infections, malignancies, surgical interventions, and events linked to the disease activity of systemic lupus erythematosus (SLE). Herein, we present a case of CAPS with multiorgan ischemia following ischemic stroke. Case Presentation: In this case report, a 33-year-old woman with a history of SLE and prolonged steroid use manifested impaired consciousness. Detection of the right internal carotid artery (ICA) occlusion led to successful ICA recanalization through endovascular thrombectomy. Postoperatively, she experienced pulmonary embolism and renal infarction. Although antiphospholipid syndrome (APS) was suspected, APS-related antibodies were negative. Anticoagulation therapy was initiated, presuming corticosteroid-induced thrombosis. However, she developed multiorgan thrombosis, culminating in multiple organ failure. Based on her clinical course, a diagnosis of CAPS was established. Intensive care and plasma exchange therapy were instrumental in her recovery, and she was discharged with a modified Rankin Scale score of 4. Conclusion: When encountering multiorgan ischemia following ischemic stroke in a young adult patient with an autoimmune disease, the consideration of CAPS as a differential diagnosis is crucial, even if APS-related antibodies test negative.