A pulmonary embolism (PE) is defined as a sudden blockage of a major blood vessel (artery) in the lung, generally brought on by a blood clot. Often times the clot is small and not deadly, but they can damage the lung. However, the clot could become life-threatening if it is so large that it blocks blood flow to the lung. Most blood clots originate in the legs (referred to as DVT), however, they can also form in arm veins, the right side of your heart and even at the tip of a catheter placed in a vein. Women have reported developing a pulmonary embolism while using the Yasmin birth control pill.

Pulmonary Embolism Symptoms
Symptoms of pulmonary embolism can vary, depending on how much of your lung is involved, the size of the clot, the number of blood clots and your overall health. Common symptoms include:

•    Sudden shortness of breath, whether active or at rest. (This symptom is most common)
•    Chest pain that often simulates that of a heart attack. The pain can occur anywhere in the chest and may radiate to the shoulder, arm, neck or jaw. It may be a sharp/stabbing or aching/dull and could become worse when you breathe deeply, cough, eat, bend or stoop. The pain often gets worse with exertion but will not go away when you rest.
•    A cough that brings up pink, foamy mucus.
•    Rapid heartbeat.

Other signs and symptoms could include: wheezing, leg swelling, clammy or bluish-colored skin, excessive sweating, anxiety, weak pulse, lightheaded feeling or fainting, and fever.

PE Causes
Pulmonary embolism, in most cases, is caused when a blood clot in the leg breaks loose and travels to the lungs. Blood clots that occur in veins close to the skin are not likely to cause problems; it is the deep vein thrombosis that can lead to pulmonary embolism, called venous thromboembolism (having both pulmonary embolism and DVT). There are other, however rarer, conditions that could block and artery; such as tumors, air bubbles, amniotic fluid, or fat that is released into the blood vessels when a bone is broken.

Diagnosis
Because the symptoms of pulmonary embolism are so similar to those of many other problems, such as heart attack or pneumonia, it can be hard to diagnose. Because of this your doctor will start with a physical exam, and will ask questions regarding your health and may perform one or more tests to help find the cause of your symptoms.

These tests may include the following:
1. Chest x-ray. This diagnostic test does not diagnose pulmonary embolism, but it may help rule out conditions that are similar (such as pneumonia).

2. Lung Scan. A ventilation-perfusion scan (V/Q scan) uses small amounts of radioactive tracers to study airflow and blow flow in your lungs. A normal lung scan may rule out pulmonary embolism but not DVT so other tests are often required.

3. Spiral computerized tomography (CT) scan. A spiral or helical CT is quickly becoming the primary initial test for diagnosing suspected pulmonary embolism. Using a dye to help visualize the area, the scan rotates continuously around your body, following a spiral path to create 3-D images. It can detect abnormalities with a greater degree of precision and is faster than traditional CTs.

4. Pulmonary angiogram. This test provides a clear picture of the blood flow in the arteries of your lungs. It is the most accurate way to diagnose pulmonary embolism, but because it requires a high degree of skill to administer and carries potentially serious risks, it is usually performed when other tests fail to provide a definitive diagnosis.

5. Tests for Blood Clots. In addition to tests that check for PE, you may also have tests that aid in diagnosing blood clots in your veins, such as: D-dimer blood test, ultrasound, venography, MRI, and blood tests that look for inherited defects in your clotting system. Women using Yasmin birth control need to be aware of blood clot symptoms, and seek medical attention if they show any signs of deep vein thrombosis or pulmonary embolism.