Severe Pediatric Arterial Thrombosis in Antiphospholipid Syndrome and Systemic Lupus Erythematosus: A Case Report.

Systemic lupus erythematosus (SLE) is a chronic, multisystem immune-mediated disease that can affect any organ system. One of its most significant complications is antiphospholipid syndrome (APS), an autoimmune disorder characterized by thrombosis, which typically presents with venous thrombosis in children. We report a 14-year-old previously healthy girl presenting with progressive right foot cyanosis and ulcerative lesions. Examination revealed digital necrosis, absent distal pulses, and delayed capillary refill. Laboratory findings included elevated antiphospholipid antibodies (aPLs), positive antinuclear antibodies (ANAs), hypocomplementemia, prolonged activated partial thromboplastin time (aPTT), and a reactive Venereal Disease Research Laboratory (VDRL) test. Imaging confirmed occlusion of the anterior tibial and peroneal arteries. She was diagnosed with critical limb ischemia due to APS secondary to SLE. Treatment with intravenous methylprednisolone, anticoagulation, antiplatelet agents, and vasoprotective therapy led to significant improvement, avoiding surgical intervention. APS secondary to SLE is uncommon in pediatric patients, and arterial thrombosis is an especially rare initial manifestation. Juvenile SLE often presents with non-specific symptoms such as arthralgias, headache, fever, and weight loss, which were absent in our patient. Instead, initial symptoms included intermittent claudication-like pain and digital necrosis, likely resulting from endothelial cell proliferation, intimal hyperplasia, endothelial dysfunction, platelet activation, and complement consumption, leading to progressive luminal narrowing and thrombosis. The lack of validated pediatric classification criteria for APS secondary to SLE complicates management decisions. This case underscores the importance of early recognition and prompt initiation of anticoagulation, immunosuppression, and vasoprotective therapy to prevent irreversible tissue damage and the need for surgical intervention.