Pulmonary embolism symptoms can vary greatly, depending on how much of your lung is involved, the size of the clots (almost never single) and your overall health — especially the presence or absence of underlying lung disease or heart disease.
Common signs and symptoms include:
- Shortness of breath. This symptom typically appears suddenly and always gets worse with exertion.
- Chest pain. You may feel like you're having a heart attack. The pain may become worse when you breathe deeply (pleurisy), cough, eat, bend or stoop. The pain will get worse with exertion but won't go away when you rest.
- Cough. The cough may produce bloody or blood-streaked sputum.
Other signs and symptoms that can occur with pulmonary embolism include:
- Leg pain or swelling, or both, usually in the calf
- Clammy or discolored skin (cyanosis)
- Excessive sweating
- Rapid or irregular heartbeat
- Lightheadedness or dizziness
When to see a doctor
Pulmonary embolism can be life-threatening. Seek immediate medical attention if you experience unexplained shortness of breath, chest pain or a cough that produces bloody sputum.
Pulmonary embolism occurs when a clump of material, most often a blood clot, gets wedged into an artery in your lungs. These blood clots most commonly originate in the deep veins of your legs, but they can also come from other parts of your body. This condition is known as deep vein thrombosis (DVT).
Occasionally, other substances can form blockages within the blood vessels inside your lungs. Examples include:
- Fat from within the marrow of a broken long bone
- Part of a tumor
- Air bubbles
It's rare to have a single pulmonary embolism. In most cases, multiple clots are involved. The lung tissue served by each blocked artery is robbed of blood and may die. This makes it more difficult for your lungs to provide oxygen to the rest of your body.
Although anyone can develop blood clots and subsequent pulmonary embolism, certain factors can increase your risk.
You're at higher risk if you or any of your family members have had venous blood clots or pulmonary embolism in the past. This may be due to inherited disorders that affect blood clotting.
In addition, certain medical problems put you at risk, such as.
- Heart disease. High blood pressure and cardiovascular disease make clot formation more likely.
- Cancer. Certain cancers — especially pancreatic, ovarian and lung cancers, and many cancers with metastasis — can increase levels of substances that help blood clot, and chemotherapy further increases the risk. Women with a history of breast cancer who are taking tamoxifen or raloxifene also are at higher risk of blood clots.
Blood clots are more likely to form in your legs during periods of inactivity, such as:
- Bed rest. Being confined to bed for an extended period after surgery, a heart attack, leg fracture or any serious illness makes you far more vulnerable to blood clots. When the lower extremities are horizontal for long periods of time, the flow of venous blood slows and blood pools in the legs.
- Long journeys. Sitting in a cramped position during lengthy plane or car trips slows blood flow, which contributes to the formation of clots in your legs.
Surgery is one of the leading causes of problem blood clots, especially joint replacements of the hip and knee. During the preparation of the bones for the artificial joints, tissue debris may enter the bloodstream and contribute to causing a clot. Simply being immobile during any type of surgery can lead to the formation of clots. The risk increases with the length of time you are under general anesthesia. For this reason, most people undergoing the type of surgery predisposing them to DVT will receive medication before and after surgery to prevent clot formation and continued after surgery.
Other risk factors
- Smoking. For reasons that aren't well understood, tobacco use predisposes some people to blood clot formation, especially when combined with other risk factors.
- Being overweight. Excess weight increases the risk of blood clots — particularly in women who smoke or have high blood pressure.
- Supplemental estrogen. The estrogen in birth control pills and in hormone replacement therapy can increase clotting factors in your blood, especially if you smoke or are overweight.
- Pregnancy. The weight of the baby pressing on veins in the pelvis can slow blood return from the legs. Clots are more likely to form when blood slows or pools.
Pulmonary embolism can be life-threatening. About one-third of people with undiagnosed and untreated pulmonary embolism don't survive. When the condition is diagnosed and treated promptly, however, that number drops dramatically.
Pulmonary embolism can also lead to pulmonary hypertension, a condition in which the blood pressure in your lungs and right side of the heart is too high. When you have obstructions in the arteries inside your lungs, your heart must work harder to push blood through those vessels. This increases the blood pressure within these vessels and the heart and can wear out a section of your heart.
In rare cases, small emboli frequently develop, resulting in chronic thrombotic pulmonary embolism.
Preventing clots in the deep veins in your legs (deep vein thrombosis) will help prevent pulmonary embolism. For this reason, most hospitals are aggressive about taking measures to prevent blood clots:
- Anticoagulants. Anticoagulants are given to people at risk of clots before and after an operation — as well as to people admitted to the hospital with a heart attack, stroke or complications of cancer.
- Graduated compression stockings. Compression stockings steadily squeeze your legs, helping your veins and leg muscles move blood more efficiently. They offer a safe, simple and inexpensive way to keep blood from stagnating after general surgery.
- Pneumatic compression. This treatment uses thigh-high or calf-high cuffs that automatically inflate with air and deflate every few minutes to massage and squeeze the veins in your legs and improve blood flow.
- Physical activity. Moving as soon as possible after surgery can help prevent pulmonary embolism and hasten recovery overall. This is one of the main reasons your nurse may push you to get up, even on your day of surgery, and walk despite pain at the site of your surgical incision.
Prevention while traveling
The risk of blood clots developing while traveling is low, but increases as travel increases. If you have risk factors for blood clots and you're concerned about traveling, talk with your doctor. He or she might suggest the following steps to help prevent blood clots from forming:
- Take a break from sitting. Move around the airplane cabin once an hour or so. If you're driving, stop every hour and walk around the car a couple of times. Do a few deep knee bends.
- Fidget in your seat. Flex, extend and rotate your ankles or press your feet against the seat in front of you, or try rising up and down on your toes. And don't sit with your legs crossed for long periods of time.
- Drink plenty of fluids. Water is the best liquid for preventing dehydration, which can contribute to the development of blood clots. Avoid alcohol, which contributes to fluid loss.
- Wear support stockings. Your doctor may recommend these to help promote circulation and fluid movement in your legs. Fortunately, compression stockings no longer look like something your grandmother would wear — they're available in a range of stylish colors and textures. There are even devices, called stocking butlers, to help you put on the stockings.