Life threatening pulmonary embolus in a factor V Leiden carrier on oral contraceptives: a case report.

Venous thromboembolism is a serious, potentially lethal health problem affecting one per 1,000 people annually. Major surgery, the use of oral contraceptives, complicated pregnancy, fractures, and immobilization increase the risk of thrombosis. In addition to these factors, thrombosis is associated with inherited deficiencies of antithrombin III, protein C, and protein S. Together these do not account for more than five to 10% of the cases. Hereditary activated protein C resistance has been recognized as a basis for a majority of cases of familial thrombosis. It accounted for more than a 10 times higher number than that of other known genetic defects. We describe a case of a young female who presented with a pulmonary embolism and was discovered to have activated protein C resistance. This patient had a heterozygous mutation for factor V Leiden and was taking oral contraceptives. This report underlines: 1) increased risk of venous thrombosis in oral contraceptive users who carry factor V Leiden mutation associated with functional resistance to the normal anticoagulation activities of protein C; 2) most episodes occurring in the young are minor, but pulmonary embolus can occur; 3) the importance of identifying other affected members of the family; and 4) the importance of anticoagulation prophylaxis at times of enhanced risk, particularly during pregnancy, postpartum, and major surgery.