What Is a Pulmonary Embolism?
A pulmonary embolism (PE) is a blood clot that develops in a blood vessel elsewhere in the body (most commonly from the leg), travels to an artery in the lung, and forms an occlusion (blockage) of the artery.
A blood clot (thrombus) that forms in a blood vessel in one area of the body, breaks off, and travels to another area of the body through the bloodstream is called an embolus. An embolus can lodge itself in a blood vessel, blocking the blood supply to a particular organ. This blockage of a blood vessel by an embolus is called an embolism.
An embolism to the lung may cause serious life-threatening consequences and, potentially, death. Most commonly, a PE is the result of a condition called deep vein thrombosis(blood clot in the deep veins of the leg).
- It is estimated that each year more than 600,000 patients suffer a pulmonary embolism.
- PE causes or contributes to up to 200,000 deaths annually in the United States.
- One in every 100 patients who develop DVT die due to pulmonary embolism.
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Venous clots most often occur in the deep veins of the legs. This condition is called deep vein thrombosis, or deep vein clot. Once a clot has formed in the deep veins of the leg, there is a potential for part of the clot to break off and travel (embolize) through the bloodstream to another area of the body. Deep vein thrombosis is the most common cause of a pulmonary embolism. Therefore, the term venous thromboembolism (VTE) may refer to deep vein thrombosis and/or the complication, pulmonary embolism.
Other less frequent sources of pulmonary embolism are a fat embolus, amniotic fluid embolus, air bubbles, and a deep vein thrombosis in the upper body. Clots may also form on the end of an indwelling intravenous (IV) catheter, break off, and travel to the lungs.
What are the risk factors for pulmonary embolism?
Risk factors that are associated with the processes that may increase the risk of a venous thromboembolism include:
- Genetic conditions that increase the risk of blood clot formation
- Surgery or trauma (especially to the legs)
- Situations in which mobility is limited, such as extended bed rest, flying or riding long distances, or paralysis
- Previous history of clots
- Older age
- Cancer and cancer therapyIf massive pulmonary embolism can be diagnosed and appropriate therapy started, the mortality can be reduced from approximately 30% to less than 10%.
What Are the Symptoms of a Pulmonary Embolism?
The following are the most common symptoms for pulmonary embolism (PE). However, each individual may experience symptoms differently:
- Sudden shortness of breath (most common)
- Chest pain (usually worse with breathing)
- A feeling of anxiety
- A feeling of dizziness, lightheadedness, or fainting
- Palpitations (heart racing)
- Coughing up blood (hemoptysis)
- Sweating
- Low blood pressure
- Symptoms of deep vein thrombosis, such as:
- Pain in the affected leg (may occur only when standing or walking)
- Swelling in the leg
- Soreness, tenderness, redness, and/or warmth in the leg(s)
- Redness and/or discolored skin
You may or may not have these symptoms should a pulmonary embolism occur. Usually, if a PE is suspected, the physician will check your legs for evidence of a deep vein thrombosis.
The type and extent of symptoms of a pulmonary embolism will depend on the size of the embolism and whether the person already has existing heart and/or lung problems.
The symptoms of a pulmonary embolism may resemble other medical conditions or problems. Always consult your physician for a diagnosis.
What Causes a Pulmonary Embolism?
Blood clotting is a normal process that occurs in the body to prevent bleeding. The body makes blood clots and then breaks them down. Under certain circumstances, the body may be unable to break down a clot, which may result in a serious health condition.
Abnormal blood clotting in the veins is related to a combination of several problems such as “sluggish” blood flow through the veins, an over-increase in clot forming factors, and/or an injury to the blood vessel wall.
Blood clots can form in arteries and/or veins. Clots formed in veins are called venous clots. Veins of the legs can be classified as superficial veins (close to the surface of the skin) or deep veins (located near the bone and surrounded by muscle).
Deep vein thrombosis (DVT) a major cause
Left untreated, a deep vein thrombosis (DVT) can break off and travel in the circulation, getting trapped in the lung, where it blocks the oxygen supply, causing heart failure. This is known as a pulmonary embolism, which can be fatal.
With early treatment, people with DVT can reduce their chances of developing a life threatening pulmonary embolism to less than one percent. Blood thinners are effective in preventing further clotting and can prevent a pulmonary embolism (PE) from occurring.
Venous clots most often occur in the deep veins of the legs. This condition is called deep vein thrombosis, or deep vein clot. Once a clot has formed in the deep veins of the leg, there is a potential for part of the clot to break off and travel (embolize) through the bloodstream to another area of the body. Deep vein thrombosis is the most common cause of a pulmonary embolism. Therefore, the term venous thromboembolism (VTE) may refer to deep vein thrombosis and/or the complication, pulmonary embolism.
Other less frequent sources of pulmonary embolism are a fat embolus, amniotic fluid embolus, air bubbles, and a deep vein thrombosis in the upper body. Clots may also form on the end of an indwelling intravenous (IV) catheter, break off, and travel to the lungs.
What are the risk factors for pulmonary embolism?
Risk factors that are associated with the processes that may increase the risk of a venous thromboembolism include:
- Genetic conditions that increase the risk of blood clot formation
- Surgery or trauma (especially to the legs)
- Situations in which mobility is limited, such as extended bed rest, flying or riding long distances, or paralysis
- Previous history of clots
- Older age
- Cancer and cancer therapy
- Certain medical conditions, such as heart failure, chronic obstructive pulmonary disease (COPD), hypertension (high blood pressure), stroke, deep vein thrombosis (DVT), and inflammatory bowel disease (chronic inflammation of the digestive tract)
- Certain medications, such as oral contraceptives (birth control pills) and hormone replacement therapy (estrogen pills for post-menopausal women)
- Pregnancy (during and after pregnancy, including cesarean section)
- Obesity
- Varicose veins (enlarged veins in the legs)
- Cigarette smoking
A risk factor is anything that may increase a person’s chance of developing a disease. It may be an activity, such as smoking, diet, family history, or many other things. Different diseases have different risk factors.
Although these risk factors increase a person’s risk, they do not necessarily cause the disease. Some people with one or more risk factors never develop the disease, while others develop disease and have no known risk factors. Knowing your risk factors to any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.
How Is Pulmonary Embolism Diagnosed?
Pulmonary embolism (PE) is often difficult to diagnose because the signs and symptoms of PE mimic those of many other conditions and diseases.
In addition to a complete medical history and physical examination, diagnostic procedures for a pulmonary embolism may include:
- Laboratory tests – Blood tests to check the blood’s clotting status. Other blood work may include testing for genetic (inherited) disorders that may contribute to abnormal clotting of the blood. In addition, arterial blood gases may be checked to determine the amount of oxygen in the blood.
- Procedures may also include any combination of the following:
Treatment for Pulmonary Embolism:
Specific treatment will be determined by your physician based on:
- Your age, overall health, and medical history
- Extent of the disease
- Your signs and symptoms
- Your tolerance for specific medications, procedures, or therapies
- Expectations for the course of the disease
- Your opinion or preference
Treatment options for pulmonary embolism include:
An important aspect of treatment of pulmonary embolism is prophylactic (preventative) treatment to prevent formation of additional embolisms.
Prevention of pulmonary embolism:
Because pulmonary embolism is caused by an embolus formed elsewhere in the body (generally in the legs), and because it is often difficult to detect presence of a venous embolus prior to the onset of complications such as a pulmonary embolism, the prevention of these emboli is necessary in the prevention of PE.
In order to prevent pulmonary embolism, the only effective way is to prevent deep vein thrombosis. Prophylactic treatment to prevent DVT includes non-invasive mechanical measures.
Mechanical measures to prevent DVT include:
- Compression stockings (elastic stockings that squeeze or compress the veins and prevent blood from flowing backward)
- Pneumatic compression devices (sleeves on the legs that are connected to a machine that provides alternating pressure on the legs)
- Getting up and moving as soon as possible after surgery or illness, as movement can help to prevent clots from forming by stimulating blood circulation
Medication: Anticoagulants are often given prophylactically to prevent DVT.
Many patients remain at risk for development of DVT for a period of time after they are either discharged from the hospital or transferred to a different type of care facility. It is important that prophylactic treatment for DVT continue until the risk for DVT development has been resolved.