Pulmonary embolism

Obstruction of the pulmonary artery or one of its branches in the lung by an embolus, usually after a deep vein thrombosis (see thrombosis, deep vein). If the embolus is large enough to block the main pulmonary artery, or if there are many clots, the condition is life-threatening. Pulmonary embolism is more likely after recent surgery, pregnancy, and immobility. A massive embolus can cause sudden death. Smaller emboli may cause severe shortness of breath, rapid pulse, dizziness, chest pain made worse by breathing, and coughing up of blood. Tiny emboli may produce no symptoms, but, if recurrent, may eventually lead to pulmonary hypertension. A diagnosis may be made by a chest X-ray, radionuclide scanning, and pulmonary angiography. An ECG and venography may also be performed. Treatment depends on the size and severity of the embolus. A small one gradually dissolves and thrombolytic drugs may be given to hasten this process. Anticoagulant drugs are given to reduce the chance of more clots. Surgery may be needed to remove larger clots.


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