What is a pulmonary embolism (PE)
A pulmonary embolism is a blood clot in one of the pulmonary arteries in the lung. The word pulmonary refers to the lungs and embolism is a blockage in a blood vessel, hence the term pulmonary embolism. A blood clot that lodges in an artery in the lungs usually travels there from a different part of the body. A blood clot in a different part of the body is called a DVT (deep venous thrombosis) and a common spot for one to form is in the leg. The clot can break off and travel in the bloodstream eventually lodging in the lungs and blocking off blood flow to that portion of the lung. This then limits/inhibits oxygen exchange between this affected portion of your lung and your blood. The lungs function to bring oxygen into the body. The blood vessels which lie close to the lung tissue exchange the oxygen into the bloodstream to take to all other tissue in the body. A blockage of a portion of your lung from a pulmonary embolism makes it more difficult for your body to bring oxygen to other tissues and you body must work harder to oxygenate the blood with less available lung tissue. This is a life threatening condition.
What are the risk factors for pulmonary embolism?
Cancer
Inherited blood clotting disorder
Bed rest (such as a prolonged hospital stay) or immobility
Surgery - increased risk from the injury of surgery itself as well as prolonged bed rest
Being overweight/obesity - increases the pressure on your veins and increases risk of DVT
Pregnancy - increased pressure on veins
Birth control pills or hormone replacement - increases the coagulability (ability to clot) of blood
Smoking - affects blood clotting and circulation
History of cardiovascular disease, high blood pressure, or stroke
Why does cancer increase the risk of pulmonary embolism?
As previously discussed in my blog on blood clots, there is clear evidence that a link has been established between cancer and blood clots. There are several explanations for this link:
Cancer itself may increase the incidence of blood clots: cancer and/or tumors may release chemicals that trigger clotting
Mass effect from a tumor: depending upon the location of a solid tumor, if near a vessel the tumor itself could press against the blood vessel, causing damage or inflammation and increase the risk of a blood clot forming.
Treatment for cancer: many drugs that are used to treat cancer also increase the activation of clotting factors which leads to an increased incidence of blood clots.
Radiation: radiation can damage a blood vessel, causing inflammation and damage which increases the risk of a blood clot
If an individual already has an established risk factor for blood clots (listed above), cancer adds to the risk, increasing it even further.
What are the symptoms of a pulmonary embolism?
Shortness of breath
Chest pain
Cough
Rapid heartbeat or irregular heartbeat
Dizziness or lightheadedness
Rapid breathing
Sweating or feeling clammy
Leg pain or swelling, especially in one leg
How is a pulmonary embolism diagnosed?
A CT scan of the chest with IV contrast is the optimal study to assess the arteries in the lungs for a blood clot.
What is the treatment for a pulmonary embolism?
Treatment for a pulmonary embolism is to thin out the blood with an anticoagulant or blood thinner. Anticoagulants are continued for a minimum of 3 months but may be continued indefinitely depending on your risk factors. For large blood clots, it may be necessary to break up the clot with medication or intervention. Smaller clots will be reabsorbed by the body.
Can you help prevent a blood clot?
Unfortunately some risk factors are not under our control but there are some areas where you could reduce your risk. Take control where you can and work on the following recommendations to reduce your risk of blood clots.
Try not to sit or stand for more than one hour at a time, get up and move to keep the blood in your legs circulating.
Long travel has been associated with increased incidence of blood clots in the legs. During long travel in the car or on a plane, make sure to get up every hour to move your legs.
Wear compression stockings if prescribed. This helps the blood to keep circulating
Exercise - there is a theme here, moving your body helps decrease the incidence of clot
Lifestyle changes - if overweight, losing weight can help decrease your risk
Smoking cessation - smoking increases the risk of blood clots