Pulmonary Embolism

An embolus is a small clot of foreign material usually a blood clot but sometimes a globule of fat, an air bubble, tissue from a tumor, or a clump of bacteria—that blocks an artery.

Most emboli come from blood clots (called thrombi) in the veins of the lower extremities or pelvis. They are carried by the bloodstream through the right side of the heart to the lungs. They also may arise from the walls of the heart. If a clot arises in the left side of the heart, the embolus will not go to the lungs but instead will go to the brain or some other part of the body. Tissue death (infarction) occurs when the blood supply to the tissue is blocked.

An embolism (sudden blockage caused by an embolus) can occur in any small artery, but the lungs are particularly vulnerable because all of the blood in your body passes through your lungs every time it circulates.

Pulmonary emboli affect as many as 500,000 persons in the United States yearly and may cause as many as 50,000 deaths each year. In persons under age 45, it occurs more often in women than in men; after that age it occurs equally in both sexes. Surgery, prolonged bed rest or inactivity (such as prolonged sitting when on a car or airplane trip), stroke, heart attack, obesity, and hip or leg fracture increase your risk of having a pulmonary embolism. Also, anything that increases the tendency of your blood to clot may make you more susceptible.

Symptoms and Signs:

1. Chest pain
2. Anxiety
3. Cough that produces blood streaked sputum
4. Excessive sweating.
5. Sudden loss of consciousness.

Diagnosis:

The symptoms depend on the size of the embolus and how healthy your cardiopulmonary system is. They in clude sudden chest pain, shortness of breath, a feeling of anxiety, sweating, and cough that sometimes produces blood streaked sputum. Massive embolism or embolism occurring in a person with serious preexisting heart or lung disease may cause sudden loss of consciousness and even death.

Pulmonary thromboembolism may be difficult to diagnose, particularly if you have underlying cardiopulmonary disease. Your physician may need a chest x-ray, a lung scan, or a pulmonary angiogram (dye is injected into an artery of the arm or leg and then flows into the arteries of the lung so that they are highlighted on the x-ray). Pulmonary angiography is the most accurate test for detecting emboli; however, it requires a high degree of experience to perform and interpret correctly. Your physician may recommend other tests as well.

What will happen if you develop pulmonary embolism?

Pulmonary embolism can be very serious; about 10 percent of affected persons die within the first hour. However, if you survive the initial attack and have appropriate diagnosis and treatment, the outcome is good. You should return to normal in a few weeks unless other serious disease is present.

Treatment:

Medication: Your physician may prescribe anticoagulant (blood thinner) therapy to prevent further blood clots from forming or clots already present from enlarging. Heparin usually is the drug that is given, often in conjunction with warfarin. Other medications may be given in order to dissolve existing clots. All of these medications do have side effects. Their use must be closely monitored.

Surgery: Surgery is rarely necessary, but it may be helpful in persons with recurring emboli for whom other treatments have not been effective or with a sudden, massive embolus. Usually a sieve like device is placed in your inferior vena cava to trap blood clots and prevent them from reaching your lungs.

Prevention:

1. After an operation, you will be encouraged to get up and move around as soon as possible or to perform active and passive leg exercises.
2. When on a trip, walk periodically or at least wiggle your toes and move your feet while sitting.
3. If you are immobilized (due to a fracture), keep your legs elevated and perhaps wear support stockings. All of these can help prevent pooling and clotting of blood in your legs, a frequent cause of emboli.
4. In some cases, if you are at risk for recurrent pulmonary embolism, you may be helped by taking low doses of heparin, warfarin (Coumadin), or antiplatelet drugs such as aspirin.