Pulmonary embolism (PE) is a blockage in one or more arteries of the lungs or one of the branches by a blood clot that travel to your lungs from another part of your body — most commonly, your legs, or a substance that has travelled from elsewhere in the body through the bloodstream (embolism). PE most commonly results from deep vein thrombosis (DVT) (a blood clot in the deep veins of the legs or pelvis, or veins farthest from the surface of the body) that breaks off and migrates to the lung, a process termed venous thromboembolism (VTE). A small proportion of cases are due to the embolization of air, fat, talc in drugs of intravenous drug abusers or amniotic fluid. The obstruction of the blood flow through the lungs and the resultant pressure on the right ventricle of the heart lead to the symptoms and signs of PE. The risk of PE is increased in various situations, such as cancer or prolonged bed rest.
Pulmonary embolism can also occur in otherwise healthy people and all times can be life-threatening, but immediate treatment with anti-clotting medications can greatly reduce the risk of death. Taking measures to prevent blood clots in your legs also can help protect you against pulmonary embolism.
Symptoms of pulmonary embolism include sudden and unexplained shortness of breath, chest pain on inspiration, and palpitations and a cough that may bring up blood-tinged sputum. Clinical signs include low blood oxygen saturation and cyanosis, rapid breathing, and a rapid heart rate. Severe cases of PE can lead to collapse, abnormally low blood pressure, and sudden death