Recurrent thrombosis in a young female: unmasking protein S deficiency

Background: Hereditary protein S deficiency is a rare but significant cause of unprovoked, recurrent venous thromboembolism (VTE) in young individuals. Early recognition is essential to prevent recurrence and complications. Case Presentation: A 23-year-old female with previous episodes of deep vein thrombosis (DVT) in 2022 and 2023 presented with acute dyspnea. Imaging revealed pulmonary thromboembolism with bilateral DVT. Coagulation testing confirmed protein S deficiency. She received systemic thrombolysis with tenecteplase followed by heparin infusion and was later transitioned to longterm direct oral anticoagulants. Cardiac function improved following treatment. Conclusion: This case highlights the importance of considering hereditary protein S deficiency in young patients with recurrent VTE, where early diagnosis and lifelong anticoagulation can prevent morbidity and improve outcomes.