Your blood's ability to form clots can save your life if you're bleeding. But when clots form inside your veins and circulate to your lungs, you may be faced with a life-threatening situation. This type of blood clot -- known as a pulmonary embolism, or PE -- can affect people of all ages. Knowing the signs, symptoms and risk factors for a PE is important because early diagnosis and treatment greatly improve the chance for recovery from this serious condition.
Origin of Lung Clots
A lung blood clot usually begins elsewhere in the body, typically as a clot in the deep leg veins, known as a deep venous thrombosis, or DVT. When DVTs form, they sometimes break apart into smaller pieces and travel through the circulation to arteries in the lungs. DVTs involving veins at or above the knee are more likely to give rise to a PE than those in the calf. When clot pieces from a DVT lodge in the arteries of the lungs, they block blood flow. This blockage can interfere with the lungs' ability to transfer fresh oxygen to the blood, leading to breathing difficulties and problems with other organs in the body that need oxygen to function normally.
Signs and Symptoms
PEs that cause a significant decrease in blood flow through the lungs can affect the function of both the lungs and the heart. The blockage interferes with oxygen uptake by the lungs and causes a backup of blood in the heart. These problems cause symptoms such as shortness of breath, chest pain and cough. The severity of PE symptoms generally increases with the size of the clot in your lungs. In extreme cases, a large PE can quickly bring on severe shortness of breath, rapid breathing, a racing heart rate, dizziness, confusion and possible collapse into unconsciousness within minutes. At the other end of the spectrum, small PEs can occur without symptoms and may only be detected incidentally.
The risk for PE increases with age, and most people who develop a lung clot are older than 60. Inactivity is also a risk factor, such as being bedridden or sitting for long periods while driving or on a plane. Obesity, cancer, heart failure and recent injury or surgery -- especially involving the legs or hips -- also increase the risk for PE. Weaker risk factors for PE include pregnancy, childbirth, smoking and use of some hormone medications. A tendency to form DVTs and PEs can also run in families.
Treatments for Pulmonary Embolism
Treatment for a PE typically includes blood thinners, called anticoagulants. These medicines stop lung clots from getting larger and prevent new ones from forming. A large lung clot might be treated with a "clot-busting" medicine to dissolve it or a procedure to remove it. Treatments are also given to control negative effects of a PE on the heart and to stabilize breathing. In more severe cases, a small filter is sometimes placed into a large vein to prevent more blood clots from traveling to the lungs.
Warnings and Precautions
If you experience symptoms of a lung blood clot, it is important to seek emergency care immediately, especially if you have risk factors for PE development. Left untreated, lung blood clots can cause death. However, treatments for PE are very effective in preventing death when given in a timely manner. Also see your doctor as soon as possible if you have signs or symptoms of a DVT, such as sudden swelling, tenderness and/or aching in one leg. Treatment of a high-risk DVT is important to reduce the chance of a lung clot.
- Circulation: AHA Scientific Statement Management of Massive and Submassive Pulmonary Embolism, Iliofemoral Deep Vein Thrombosis, and Chronic Thromboembolic Pulmonary Hypertension
- American Family Physician: DVT and Pulmonary Embolism: Part II. Treatment and Prevention
- PDR Health: Blood Clots: Pulmonary Embolism
- Deep Vein Thrombosis and Pulmonary Embolism: A Guide for Practitioners
- Blood: How I Treat Incidental Pulmonary Embolism
- American Family Physician: DVT and Pulmonary Embolism: Part I. Diagnosis