Protein S Deficiency Presented as Pulmonary Artery Thromboembolism: a Case Report

Protein S deficiency is a rare, autosomal-dominant hereditary coagulation disorder that is associated with recurrent and spontaneous development of venous thrombosis. This case report highlights protein S deficiency as a cause of pulmonary thromboembolism in East Asian patients, suggesting its consideration in populations with higher prevalence. We herein describe a case of a 34-year-old Chinese man who developed his first thrombotic episode manifesting as pulmonary artery thromboembolism. Thrombophilia screening revealed protein S deficiency; his protein S activity was 29% (normal range, 60–140%). IVC filter implantation was suggested to the patient as a prophylactic measure, but he preferred rivaroxaban anticoagulation. On follow-up after 349 days, there was persistence but reduction in pulmonary embolism. This case highlights the importance of testing for protein S deficiency, especially in East Asians, as they seem to have higher rates of this condition than Caucasians. It highlights the difficulties in treating these patients, especially when deciding on things like IVC filters and long-term anticoagulants. This case emphasizes that individualized treatment options should be considered in patients with protein S deficiency and that the process must be accomplished under very close supervision.