Pulmonary Embolism

A pulmonary embolism (PE) happens when a clot blocks blood flow inside the lungs. Most clots begin in the deep veins of the legs — a condition called deep vein thrombosis — then break loose and travel through the heart into the pulmonary arteries. Once lodged there, the clot prevents that portion of the lung from receiving blood and performing gas exchange properly.

Symptoms can range from mild to severe and sometimes appear suddenly: sharp chest pain that worsens with a deep breath, shortness of breath that starts for no obvious reason, a racing heart, coughing (sometimes with blood-tinged mucus), and lightheadedness or fainting. Because these signs overlap with several other conditions, diagnosis typically involves imaging such as a CT pulmonary angiogram or a ventilation-perfusion scan.

Treatment usually focuses on anticoagulant medications — blood thinners — that stop the clot from growing and allow your body's natural processes to dissolve it over time. In more severe cases, clot-dissolving drugs (thrombolytics) or procedures to remove the clot may be needed. Recovery varies widely depending on the size of the clot and how quickly treatment begins, but most people go on to do well with appropriate care.

A pulmonary embolism is considered a medical emergency because a large or multiple clots can severely strain the heart and cut oxygen to vital organs within minutes. Recognizing the warning signs — sudden shortness of breath, chest pain, a rapid heartbeat — and getting emergency care quickly can be life-saving.

Understanding your personal risk factors matters too. Prolonged immobility (long flights or bed rest), certain medications, pregnancy, and some inherited clotting disorders all raise the likelihood of a PE. Knowing these factors lets you and your care team take preventive steps before problems arise.