Deep-vein blood clots: Are you at risk?

Every year, an estimated 600,000 people in the United States develop a blood clot deep inside the leg, known as deep-vein thrombosis. These clots usually develop in the lower leg, thigh, or pelvis but occasionally the arm. The affected area may be tender or painful, swollen, red or discolored, and warm to the touch. If a clot breaks free and travels to a lung, it can cause a pulmonary embolism. Symptoms of a pulmonary embolism include difficulty breathing that happens suddenly, a fast or irregular heartbeat, coughing up blood, and chest pain or discomfort, which usually worsens with a deep breath or coughing.