27 Hypercoagulable States, A A 23-year-old woman presents to the emergency department with a chief complaint of acute onset of shortness of breath. It is associated with right-sided chest pain, which increases with inspiration. She denies fever, chills, cough, or other respiratory symptoms. She has had no lower extremity swelling. She has not been ill, bedridden, or immobile for prolonged periods. Her medical history is notable for an episode about 2 years ago of deep venous thrombosis (DVT) in the right lower extremity while taking oral contraceptives. She has been otherwise healthy
and is currently taking no medications. The family history is notable for a father who died of a pulmonary embolism. On physical examination, she appears anxious and in mild respiratory distress. She is tachycardic to 110 bpm, with a respiratory rate of 20/min. She has no fever, and blood pressure is stable. The remainder of the physical examination is normal. Chest x-ray film fi is normal. Ventilationperfusion scan reveals a high probability of pulmonary embolus. Given her history of DVT, a hypercoagulable state is suspected.
1. What are the risk factors for pulmonary thromboemboli? • As first noted by the pathologist Virchow, there are three possible contributors to formation of an abnormal clot (thrombus): decreased blood fl flow, vessel injury or inflammation, fl and changes in the intrinsic properties of the blood
• Th The deep leg veins are low-fl flow, high capacity veins and are at risk for clot formation, especially during periods of immobilization • Vessel injury is common after ft surgery or trauma • Changes in the intrinsic clotting ability can be due to inherited disorders or medications