Pulmonary embolism, a severe and life-threatening condition, is caused when the pulmonary artery is blocked by foreign matter such as a blood clot (thrombus), fat, air or tumor tissue. Although there are common symptoms, each individual may experience symptoms differently. Signs and symptoms of pulmonary embolism may be similar to those of a heart attack or a lung disorder such as pneumonia. A doctor must be seen immediately. Common symptoms include sudden chest pain, excessive perspiring, shock, cyanosis (bluish skin color), anxiety and loss of consciousness. Conditions that may contribute to pulmonary embolism include extended bed rest, surgery, cancer, paralysis and aging.

Pulmonary embolism is difficult to diagnose. Non-invasive tests cannot be used in the diagnosis of pulmonary embolism. The physician must often eliminate the possibility of other lung diseases before determining that the condition is pulmonary embolism. A test called V/Q scan - a nuclear ventilation-perfusion study of the lungs - may be used, as well as a pulmonary angiography. New diagnostic methods are under investigation.

The immediate treatment for pulmonary embolism is anticoagulant therapy to dissolve the clot and return blood flow. Oxygen and sedatives may also be used to make the patient comfortable. Surgery to remove the embolism may also be performed.