Pulmonary Embolism

Definition

Pulmonary embolism is blockage in one or more arteries in your lungs. In most cases, pulmonary embolism is caused by blood clots that travel to your lungs from another part of your body — most commonly, your legs.

Pulmonary embolism is a complication of deep vein thrombosis (DVT), which is clotting in the veins farthest from the surface of the body. Pulmonary embolism can occur in otherwise healthy people. Common signs and symptoms include sudden and unexplained shortness of breath, chest pain and a cough that may bring up blood-tinged sputum.

Pulmonary embolism can be life-threatening, but immediate treatment with anti-clotting medications can greatly reduce the risk of death. Taking measures to prevent blood clots in your legs also can help protect you against pulmonary embolism.

Symptoms

Pulmonary embolism symptoms can vary greatly, depending on how much of your lung is involved, the size of the clot and your overall health — especially the presence or absence of underlying lung disease or heart disease. Common signs and symptoms include:
  • Shortness of breath:This symptom typically appears suddenly, and occurs whether you’re active or at rest.
  • Chest pain:You may feel like you’re having a heart attack. The pain may become worse when you breathe deeply, cough, eat, bend or stoop. The pain will get worse with exertion but won’t go away when you rest.
  • Cough:The cough may produce bloody or blood-streaked sputum.

Causes

Pulmonary embolism occurs when a clump of material, most often a blood clot, gets wedged into an artery in your lungs.

These blood clots most commonly originate in the deep veins of your legs, but they can also come from other parts of your body. This condition is known as deep vein thrombosis (DVT). Not all DVT blood clots result in pulmonary embolism.

Occasionally, other substances can form blockages within the blood vessels inside your lungs. Examples include: Fat from within the marrow of a broken bone, Part of a tumor, Air bubbles.

Tests and diagnosis

Pulmonary embolism can be difficult to diagnose, especially in people who have underlying heart or lung disease. For that reason, your doctor will likely order a series of tests to help find the cause of your symptoms, including:
  • Chest X-ray:This noninvasive test shows images of your heart and lungs on film. Although X-rays can’t diagnose pulmonary embolism and may even appear normal when pulmonary embolism exists, they can rule out conditions that mimic the disease.
  • Lung scan:This test, called a ventilation-perfusion scan (V/Q scan), uses small amounts of radioactive material to study airflow (ventilation) and blood flow (perfusion) in your lungs. First, you inhale a small amount of radioactive material while a special camera designed to detect radioactive substances records air movement in your lungs. Then a small amount of radioactive material is injected into a vein in your arm. Images taken after the injection show whether you have a normal or diminished flow of blood to your lungs. This test is less reliable if you’re a smoker.