Lung Disease - Pulmonary embolism

Pulmonary embolism is a condition in which a part of a blood clot in a vein breaks away and travels through the heart and into the pulmonary circulatory system. Here the vessels leading from the heart branch like a tree, gradually becoming smaller until finally they form capillaries , the smallest blood vessels. Depending on its size, the clot will at some point reach a vessel through which it cannot pass, and there will lodge itself. The clot disrupts the blood supply to the area supplied by that vessel. The larger the clot, the greater is the area of lung that loses its blood supply, and the more drastic the results to the patient.

This condition develops most commonly in association with inflammation of the veins of the legs ( thrombophlebitis ). People with varicose veins are particularly susceptible to thrombophlebitis. Because of constrictions produced by garters or rolled stockings, or just sitting with crossed legs for a long time, the sluggish blood flow already present is aggravated, and a clot may form in a vessel. Some people without varicose veins can also develop clots under the same conditions. The body often responds to the clot with the reaction of inflammation, which is painful. However, when there is no inflammatory response, there is no warning to tell that a clot has formed. In either situation there is always a chance that a piece may break off the main clot and travel to the lung. Of recent concern in this regard are studies that appear to link oral contraceptives with the incidence of clotting, thereby leading to pulmonary embolism. The number of women affected in this way by the use of oral contraceptives is small, but enough to be of concern.

The symptoms of pulmonary embolism are varied and may be minor or major. Most common are pleurisy-marked by chest pain during breathing—shortness of breath, and cough with the production of blood. Once the pulmonary embolism is diagnosed the treatment is simple in the less severe cases, which are the majority. But in cases of large clots and great areas of lung deprived of blood supply there may be catastrophic effects on the heart and general circulation.


Certain preventive measures are worthwhile for all people. Stockings should not be rolled, because that produces a constricting band about the leg that impairs blood flow and predisposes to clot formation. Especially when taking long automobile or airplane rides one should be sure to stretch the legs periodically. Individuals with varicose veins or a history of thrombophlebitis should take these precautions more seriously. People who stand still for long periods during the day should wear elastic support stockings regularly and elevate their feet part of the day and at night.

When considering the use of oral contraceptives the physician must weigh the risks of developing clots from the drug against the psychological, social, and physical risks of pregnancy. The risk from oral contraceptives is lessened if the woman does not have high blood pressure. Any persistent pain in the leg, especially in the calf or behind the knee, deserves the attention of a physician. Anyone with varicose veins or anyone taking oral contraceptives should be especially attentive to these symptoms.

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