A pulmonary embolism (PE) is an emergency medical condition that occurs in the lungs as a result of a blocked blood vessel. The blockage occurs when a blood clot dislodges from a vein (venous thrombus) in another part of the body (usually the legs) and reaches the lungs. When the clot lodges in the blood vessels of the lungs it can limit the blood supply to the lungs, causing shortness of breath and chest pain. It can be lifethreatening and needs immediate treatment.
A blood clot is a clump of platelets with red blood cells and the protein fibrin. Platelets are cells that help stop injured blood vessels from bleeding. Clots usually form to help stop bleeding, but sometimes they occur due to blood clotting abnormalities. A clot that stays in a vein is called a thrombus. One that moves to another part of the body is called an embolus. Clots can also form during long periods of inactivity if blood moves too slowly through the veins. The clot formed in another part of the body moves to the lungs through the bloodstream. Veins deep in the legs are the most common source of clots.
The most common symptoms are shortness of breath, chest pain, coughing up blood, and fast heartbeat. Nausea, fainting, sweating, wheezing, and clammy or bluish skin are others. The chest pain may last from minutes to hours.
The health care provider makes a diagnosis from an examination and symptoms. Tests include electrocardiography (ECG), chest x-ray, blood tests, computed tomography (CT) of the chest, or lung scan. Blood tests check for clotting problems (D-dimer) and lung gases such as oxygen level in the blood. In rare cases when the tests are inconclusive and pulmonary embolus is still suspected, a special x-ray known as angiography may be done. Angiography requires injecting a dye in the veins before x-rays can be taken.
Treatment involves hospitalization and intravenous medicines (heparin) to dissolve the clot and stop new ones from forming. Anticoagulant drugs (warfarin, rivaroxaban, and others) will also be given by mouth and continued for at least 3 months. Special compression stockings may help control swelling in the legs. The health care provider will suggest that people who are overweight lose weight since obesity and sedentary lifestyle are major risk factors for pulmonary embolism.
In rare cases, a special (Greenfield) filter can be put in the main vein (vena cava) going from the legs and pelvis to the heart to stop clots from getting into the lungs.
Contact the following sources: