Pulmonary Embolism

Overview

Pulmonary embolism is a blockage in one of the blood vessels in the lungs. It most often happens when a blood clot forms in a deep vein, usually in the leg or pelvis, and travels through the bloodstream to the lungs. This can reduce blood flow and make it harder for the lungs to provide oxygen to the body.

Pulmonary embolism can range from mild to life-threatening, depending on the size and number of clots and the person’s overall health. It is considered a serious medical condition that needs prompt assessment. With timely diagnosis and appropriate treatment, many people recover and can reduce the risk of future clots.

Symptoms

Symptoms of pulmonary embolism can appear suddenly or develop gradually. They may be mild in some people and severe in others. Common symptoms include:

• Sudden shortness of breath, especially at rest or with minimal activity
• Chest pain that may worsen with deep breathing, coughing or movement
• Fast or irregular heartbeat
• Cough, sometimes with blood-streaked mucus
• Lightheadedness, fainting or feeling very weak
• Sweating, anxiety or a sense that something is seriously wrong

Some people may also have symptoms of a clot in the leg, such as swelling, pain, tenderness, warmth or redness in the calf or thigh. However, a pulmonary embolism can occur without obvious leg symptoms.

Causes and Risk Factors

The most common cause of pulmonary embolism is a blood clot that starts in a deep vein, called deep vein thrombosis. When part of the clot breaks away, it can travel to the lungs and block blood flow.

Several factors can increase the risk of developing blood clots, including:

• Long periods of immobility, such as bed rest, long-distance travel or recovery after surgery
• Recent surgery or injury, especially involving the legs, hips, abdomen or pelvis
• Pregnancy and the period after childbirth
• Certain inherited or acquired clotting conditions
• Cancer or some cancer treatments
• Previous deep vein thrombosis or pulmonary embolism
• Smoking
• Excess body weight
• Use of hormone-based therapies in some people
• Older age and certain chronic medical conditions

Having one or more risk factors does not mean a person will develop pulmonary embolism, but it may increase the need for medical awareness and preventive measures in specific situations.

Diagnosis

Diagnosing pulmonary embolism usually involves a combination of medical history, physical examination and tests. A doctor will ask about symptoms, risk factors, recent surgery, travel, illness, medications and any previous blood clots.

Tests may include blood tests that help assess clotting activity, oxygen levels and the effect on the heart. Imaging tests are often used to look for clots in the lung blood vessels. Common imaging methods may include a CT scan of the chest with contrast, a ventilation-perfusion scan or ultrasound of the legs to check for deep vein thrombosis. In some cases, heart ultrasound or other tests may be needed to assess how the embolism is affecting the heart and circulation.

Because symptoms can resemble other conditions, such as pneumonia, heart attack or asthma, medical evaluation is important to confirm the cause and guide treatment.

Treatment Options

Treatment depends on the severity of the pulmonary embolism, the person’s overall health and the risk of bleeding. The main goals are to stop the clot from growing, prevent new clots and support breathing and circulation.

Many patients are treated with anticoagulant medicines, often called blood thinners. These medicines do not immediately dissolve the existing clot, but they help prevent it from getting larger and reduce the chance of further clots while the body gradually breaks it down.

In more severe cases, especially when blood pressure is very low or the heart is under strain, doctors may consider clot-dissolving treatments or procedures to remove or reduce the clot. These options are used selectively because they can carry significant risks and require specialist assessment.

Some people may need oxygen support, monitoring in hospital or treatment for an underlying cause. If anticoagulant treatment is not possible or is not effective in certain situations, a filter may be placed in a large vein to help prevent clots from reaching the lungs.

After treatment begins, follow-up care is important. Doctors may review the cause of the clot, duration of treatment, lifestyle factors and prevention strategies for the future. Preventive measures may include safe movement after surgery or long travel, management of chronic conditions and individualized clot-prevention plans for higher-risk patients.

When to See a Doctor

Pulmonary embolism can be a medical emergency. Seek urgent medical attention if you experience sudden shortness of breath, chest pain, fainting, coughing blood or a rapid heartbeat, especially if you have risk factors for blood clots.

You should also contact a healthcare professional promptly if you develop new swelling, pain, warmth or redness in one leg, particularly after surgery, injury, long travel or a period of immobility.

People with a previous blood clot, known clotting condition, cancer, recent surgery or pregnancy should discuss their individual risk with a healthcare provider. Early evaluation and appropriate prevention can help reduce complications and support safer care.