MEDizzy - A 21-year-old woman has had multiple episodes of deep venous

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Hemodynamic Disorders

A 21-year-old woman has had multiple episodes of deep venous thrombosis during the past 10 years and one episode of pulmonary thromboembolism during the past year. Laboratory tests show that her prothrombin time (PT), partial thromboplastin time (PTT), platelet count, and platelet function studies all are normal. Which of the following risk factors is the most common cause for such a coagulopathy?

ExplanationRecurrent thrombotic episodes at such a young age strongly suggest an inherited coagulopathy. The factor V (Leiden) mutation affects 2% to 15% of the population, and more than half of all individuals with a history of recurrent deep venous thrombosis have such a defect. Inherited deficiencies of the anticoagulant proteins antithrombin III and protein C can cause hypercoagulable states, but these are much less common than factor V mutation. Hyperhomocysteinemia is a less common cause of the inherited risk of thrombosis than is factor V mutation. It also is a risk factor for atherosclerosis that predisposes to arterial thrombosis. Although some cancers elaborate factors that promote thrombosis, this patient is unlikely to have cancer at such a young age; a 10-year history of thrombosis is unlikely to occur in a patient with cancer.