What is the difference between a pulmonary embolism (PE) and deep vein thrombosis (DVT)?

Both pulmonary embolism (PE) and deep vein thrombosis (DVT) are part of a broader condition known as venous thromboembolism (VTE) [2]. Although closely related, they represent two different conditions that occur in different parts of the body and have different implications.

Deep Vein Thrombosis (DVT)

DVT occurs when a blood clot forms in a deep vein within the body [3]. These clots often form in the legs, but they can also occur in the thigh, pelvis, or arm [2]. Symptoms of DVT can be subtle or entirely absent in about half of those affected [2]. However, when symptoms do appear, they usually include swelling, pain or tenderness, warmth, and redness or discoloration in the affected limb [2].

Pulmonary Embolism (PE)

A pulmonary embolism is a serious condition that occurs when a blood clot, usually from a DVT, breaks loose and travels through the bloodstream to become lodged in one of the pulmonary arteries, causing a sudden blockage [1]. This blockage can lead to permanent damage to the lungs, decreased oxygen levels in the blood, and damage to other organs due to a lack of oxygen [1]. In some cases, a PE can be life-threatening, especially if the clot is large or if there are multiple clots [1].

Symptoms of a pulmonary embolism may appear without any prior symptoms of DVT [2]. Common symptoms include shortness of breath, rapid breathing, chest pain or discomfort that worsens when coughing or taking a deep breath, an increased heart rate, a cough that may involve coughing up blood, a severe drop in blood pressure, dizziness, or fainting [1]. Sometimes, there are no symptoms until serious complications, such as pulmonary hypertension, occur [1].

Relationship and Risk Factors

The primary link between the two conditions is that DVT is often the underlying cause of a pulmonary embolism [1]. When a piece of a DVT clot breaks off and travels to the lungs, it causes a PE [2]. Therefore, preventing and treating DVT is crucial for preventing a PE.

Common risk factors for both conditions include surgery (especially joint replacement surgery), certain medical conditions like cancer and heart disease, bone fractures, hormonal medications, pregnancy and childbirth, prolonged immobility (such as bed rest or long-haul travel), advancing age (especially after 40), family history, and obesity [1].

Diagnosis and Emergency Treatment

Diagnosing both conditions requires specific tests performed by a physician [2]. If you experience any symptoms of DVT, such as swelling or pain in the leg, you should see a doctor as soon as possible [2]. If you experience symptoms of a PE, such as difficulty breathing or chest pain, you must seek medical help immediately [2].

Immediate treatment for a pulmonary embolism includes medications such as anticoagulants to prevent clots from enlarging and forming new ones [1]. In severe and life-threatening cases, clot-busting drugs (thrombolytics) may be used [1]. Other procedures may include catheter-assisted clot removal or the placement of an inferior vena cava filter [1]. Preventing new clots is essential to avoid recurrence of a PE [1]. You can learn more about this condition by visiting Pulmonary Embolism: Symptoms, Diagnosis, and Emergency Treatment (Arabic).

Medical references

• Pulmonary Embolism
• About Venous Thromboembolism (Blood Clots)
• The basics of blood clots: What you need to know